Pastebin link with footnotes: https://pastebin.com/uXSCjwZK

Nutrition

• Vegans lie to claim that health organizations agree on their diet:
  
  1. There are many health authorities that explicitly advise against vegan diets, especially for children.
  2. The Academy of Nutrition and Dietetics was founded by Seventh-day Adventists, an evangelistic vegan religion that owns meat replacement companies. Every author of their position paper is a career vegan, one of them is selling diet books that are cited in the paper. One author and one reviewer are Adventists who work for universities that publicly state to have a religious agenda. Another author went vegan for ethical reasons. They explicitly report "no potential conflict of interest". Their claims about infants and athletes are based on complete speculation (they cite no study following vegan infants from birth to childhood) and they don't even mention potentially problematic nutrients like Vitamin K or Carnitine.
  3. Many, if not all, of the institutions that agree with the AND either just echo their position, don't cite any sources at all, or have heavy conflicts of interest. E.g. the Dietitians of Canada wrote their statement with the AND, the USDA has the Adventist reviewer in their guidelines committee, the British Dietetic Association works with the Vegan Society, the Australian Guidelines cite the AND paper as their source and Kaiser Permanente has an author that works for an Adventist university.
  4. In the EU, all nutritional supplements, including B12, are by law required to state that they should not be used as a substitute for a balanced and varied diet.
  5. In Belgium, parents can get imprisoned for imposing a vegan diet on children.
• The supposed science around veganism is highly exaggerated. Nutrition science is in its infancy and the "best" studies on vegans rely on indisputably and fatally flawed food questionnaires that ask them what they eat once and then just assume they do it for several years:
  
  1. Vegans aren't even vegan. They frequently cheat on their diet and lie about it.
  2. Self-imposed dieting is linked to binge eating disorder, which makes people forget and misreport about eating the food they crave.
  3. The vast majority of studies favoring vegan diets were conducted on people who reported to consume animal products and by scientists trained at Seventh-day Adventist universities. They have contrasting results when compared other studies. The publications of researchers like Joan Sabate and Winston Craig (reviewers and authors of the AND position paper, btw) show that they have a strong bias towards confirming their religious beliefs. They brag about their global influence on diet, yet generally don't disclose this conflict of interest. They have pursued people for promoting low-carbohydrate diets.
  4. 80-100% of observational studies are proven wrong in controlled trials.
• A vegan diet is not sustainable for the average person. Ex-vegans vastly outnumber current vegans, of which the majority have only been vegan for a short time. Common reasons for quitting are: concerns about health (23%), cravings (37%), social problems (63%), not seeing veganism as part of their identity (58%). 29% had health problems such as nutrient deficiencies, depression or thyroid issues, of which 82% improved after reintroducing meat. There are likely more people that quit veganism with health problems than there are vegans. Note that this is a major limitation of cohort studies on vegans as they only analyze the people who did not quit. (survivorship bias)
  
• Vegans use appeals to authority or observational (non-causal) studies with tiny risk factors to vilify animal products. Respectable epidemiologists outside of nutrition typically reject these because they don't even reach the minimum threshold to justify a hypothesis and might compromise public health. The study findings are usually accompanied by countless paradoxes such as meat being associated with positive health outcomes in Asian cohorts:
  
  1. Vegans like to say that meat causes cancer by citing the WHO's IARC. But the report actually says there's no evaluation on poultry/fish and that red meat has not been established as a cause of cancer. More importantly, Gordon Guyatt (founder of evidence-based medicine, pescetarian) criticized them for misleading the public and drawing conclusions from cherry-picked epidemiology (they chose only 56 studies out of the supposed 800+). A third of the committee voting against meat were vegetarians. Before the report was released, 23 cancer experts from eight countries looked at the same data and concluded that the evidence is inconsistent and unclear.
  2. The idea that dietary raised cholesterol causes heart disease has never been proven.
  3. Here's a compilation of large, government-funded clinical trials to oppose the claims made to blame meat and saturated fat for diabetes, cancer or CVD. Note that these have been ignored WHO and guidelines.
  4. Much of the anti-meat push is coming from biased institutions like Adventist universities or Harvard School of Public Health who typically don't disclose their conflicts of interest. The latter conducted bribed studies for the sugar industry and was chaired by a highly influential supporter of vegetarianism for 26 years. He published hundreds of epidemiological anti-meat papers (e.g. the Nurses' Health Studies), tried to censor publications that oppose his views and wants to deemphasize the importance of experimental science. He has financial ties to seed oil, nut, fruit, vegetable and pharmaceutical industries and is part many plant-based movements like Blue Zones, True Health Initiative (Frank Hu, David Katz, Dean Ornish), EAT-Lancet and Lifestyle Medicine (Adventists, Michael Greger).
• Popular sources that promote "plant-based diets" are actually just vegan propaganda in disguise:
  
  1. Blue zones are bullshit. The longest living populations paradoxically consume the highest amount of meat. Buettner cherry-picks and ignores areas that have both high consumption of animal products and high life expectancies (Hong Kong, Switzerland, Spain, France, ... ). He praises Adventists for their health, but doesn't do the same for Mormons. Among others, he misrepresents the Okinawa diet by using data from a post WWII famine. The number of centenarians in blue zones is likely based on birth certificate fraud. The franchise also belongs to the SDA church now.
  2. The website "nutritionfacts.org" is run by a vegan doctor who is known to misinterpret and cherry-pick his data. He and many other plant-based advocates like Klaper, Kahn and Davis all happen to be ethical vegans.
  3. EAT-Lancet is pushing a nutrient deficient "planetary health diet" because it's essentially a global convention of vegans. Their founder and president is the Norwegian billionaire, hypocrite and animal rights activist Gunhild Stordalen. In 2017, they co-launched FReSH - a partnership of fertilizer, pesticide, processed food and flavouring companies.
  4. The China Study, aka the Vegan Bible, has been debunked by hundreds of people including Campbell himself in his actual peer-reviewed publications on the study.
  5. The Guardian, a pro-vegan newspaper that frequently depicts meat as bad for health and the environment, has received two grants totaling $1.78m from an investor of Impossible Foods.
• A widespread lie is that the vegan diet is "clinically proven to reverse heart disease". The studies by Ornish and Esselstyn are made to sell their diet, but rely on confounding factors like exercise, medication or previous bypass surgeries (Esselstyn had nearly all of them exercise while pretending it was optional). All of them have tiny sample size, extremely poor design and have never been replicated in much larger clinical trials, which made Ornish suggest that we should discard the scientific method. Both diets included dairy.
  
• Vegan diets are devoid of many nutrients and generally require more supplements than just B12. Some of them (Vitamin K2, EPA/DHA, Vitamin A) can only be obtained because they are converted from other sources, which is inefficient, limited or poor for a large part of the population. EPA+DHA from animal products have an anti-inflammatory effect, but converting it from ALA (plant sourced) does not seem to work the same. Taurine is essential for many people with special needs, while Creatine supplementation improves memory only in those who don't eat meat.
  
• The US supplement industry is poorly regulated and has a history of spiking their products with drugs. Vitamin B complexes were tainted with anabolic steroids in the past, while algae supplements have been found to contain aldehydes. Supplements and fortified foods can cause poisoning, while natural products generally don't. Even vegan doctors caution and can't agree on what to supplement.
  
• Restrictive dieting has psychological consequences including aggressive behavior, negative emotionality, loss of libido, concentration difficulties, higher anxiety measures and reduced self-esteem. There is an extremely strong link between meat abstention and mental disorders. While it's unknown what causes what, the vegan diet is low in or devoid of several important brain nutrients.
  
• A vegan diet alone fulfills the diagnostic criteria of an eating disorder.
  
• Patrik Baboumian, the strongest vegan on earth, lied about holding a world record that actually belongs to Brian Shaw. Patrik has never even been invited to World's Strongest Man. He dropped the weight during his "world record", which was done at a vegetarian food festival where he was the only competitor. His unofficial deadlift PR is 360kg, but the 2016 world record was 500kg. We can compare his height-relative strength with the Wilks Score and see that he is being completely dwarfed by Eddie Hall (208 vs 273). Patrik also lives on supplements. He pops about 25 pills a day to fix common vegan nutrient deficiencies and gets over 60% of his protein intake from drinking shakes.
  
• Here's a summary on almost every pro athlete that either stopped being vegan, got injured, has only been vegan a couple of years, retired or was falsely promoted as vegan.
  
• Historically, humans have always needed animal products and are highly adapted to meat consumption. There has never been a recorded civilization of humans that was able to survive without animal foods. Isotopic evidence shows that the first modern humans ate lots of meat and were the only natural predator of adult mammoths. Most of their historic technology and cave paintings revolved around hunting animals. Our abilities to throw and sweat likely developed for this reason. Our stomach's acidity is in the same range as obligate carnivores and its shape has changed so much from other hominids that we can't even digest cellulose anymore. The vegan diet is born out of ideology, species-inappropriate and could negatively affect future generations.
  
  1. The cooked starch hypothesis that vegans use is inconsistent with many observations.
• Compilations of nutrition studies:
  
  1. Veganism slaughter house (80+ papers).
  2. 70+ papers comparing vegans to non-vegans.
  3. Scrolls and tomes against the Indoctrinated.
  4. Zotero folder of 120+ papers.

Environment

• Cow farts do not cause climate change. The EPA estimates that all agriculture produces about 10% of US greenhouse emissions, while animal agriculture is less than half of that. Other developed countries, like Germany, UK and Australia all have similarly low emissions. Vegans use global estimations that are skewed by developing countries with inefficient subsistence agriculture. Their main figure is an outdated and retracted source that compared lifecycle to direct emissions.
  
• Many environmental studies that vegans use are heavily flawed because they were made by people who have no clue about agriculture, e.g. by the SDA church. A common mistake is that they use irrational theoretical models that assume we grow crops for animals because most of the plant weight is used as feed, The reality is that 86% of livestock feed is inedible by humans. They consume forage, food-waste and crop residues that could otherwise become an environmental burden. 13% of animal feed consists of potentially edible low-quality grains, which make up a third of global cereal (not total crop) production. All US beef cattle spend the majority of their life on pasture and upcycle protein even when grain-finished (0.6 to 1). Hence, UN FAO considers livestock crucial for food security and does not endorse veganism at all.
  
• Plant-to-animal food comparisons are deceiving because animals provide many actually useful by-products that are needed for medicine, crop fertilization, clothing, pet food and public water safety. Vegans are in general very dishonest when comparing foods, as seen here where they compare 1kg of beef (2600 kcal, 260g protein) to 1kg of tomatoes (180 kcal, 9g protein). The claim that we could feed more people just with more calories is also wrong because the leading causes of malnutrition are deficiencies of Iron, Zinc, Folate, Iodine and Vitamin A - which are common and most bioavailable in animal products.
  
• Vegan land use comparisons are half-truths that equate pastures with plantations. 57% of land used for feed is not even suitable for crops, while the rest is often much less productive. Grassland can sequester more carbon and has a four times lower rate of soil loss per unit area than cropland. Regenerative agriculture restores topsoil, is scalable, efficient and has high animal welfare. Big names like Kellogg are investing in it for long-term profit. On the other hand, removing livestock would create a food supply incapable of supporting the US population’s nutritional requirements due to lack of vitamin A, vitamin B12, vitamin D, calcium and fatty acids - while removing most animal by-products.
  
• Water usage is possibly the most ridiculous way vegans deceive. The water footprint is divided into green (sourced from precipitation) and blue (sourced from the surface). Water scarcity is largely dependent on blue water use, which is why experts use lifecycle models. Vegan infographics always portray beef as a massive water hog by counting the rain that falls on the pasture. 96% of beef's water usage is green and it can even be produced without any blue water at all. The crops leading to the most depletion are wheat (22%), rice (17%), sugar (7%) and cotton (7%).
  
• Going vegan won't do shit for the Amazon rainforest because the majority of Brazil's beef exports go to China and Hong Kong. The US or European countries each account for 2% or less. Soybean demand is driven by oil; the rest of the plant (80%) is a by-product that is exported as Chinese pig feed. Brazil is also a misrepresentative and atypical industry. Globally, cattle ranching accounts for 12%, commercial crops for 20% and subsistence farming for 48% of deforestation. The US use about half as much forest land for grazing than 70 years ago.
  
• Livestock is not routinely supplemented with vitamin B12. Cows that consume cobalt (found in grass, which is free of B12) produce it with gut bacteria in the rumen. Gastrointestinal animals (including humans) initially can't absorb it, but instead excrete it and can then eat their own shit. B12 is in the soil because of excretions - ground bacteria exist but have never been shown to be the main source. Plants are devoid of B12 because competing bacteria consume it, not because of soil depletion. The "90% of B12 supplements go to livestock"-figure...
  
  1. is bullshit that vegans keep on parroting. It originates from an article that calls humans herbivores, with no source.
  2. ignores the fact that you can get B12 from seafood and venison. A can of sardines provides 3x the RDA.
  3. is illogical because animals on unnatural diets can simply be given cobalt instead of the synthetic supplement that vegans rely on. Cows also destroy most of B12 in their gut before it can be absorbed.

Socioeconomics

• Voluntary veganism is a privilege that is enabled by globalization and concentrated in first-world societies. Less than 1% of Indians are vegan. Jains, who are similar to vegans, are the wealthiest Indian community and even they still drink milk. In fact, India is a great example of why veganism doesn't work because they've religiously pursued it for thousands of years and still couldn't do it. Even Gandhi was an ex-vegan that had to warn them how dangerous the diet is.

Ethics

• Veganism is a harmful ideology that promotes the abstinence from any "optional" animal suffering inflicted to support human health. For example, vaccines are not vegan. And just like meat, some people have already considered them unnecessary. Likewise, popular vegan communities also encourage people to put their carnivorous pets on a vegan diet to "avoid" cruelty. Hence, promoting animal rights is fundamentally anti-human because it will restrict or remove access to even the most basic needs, such as food or clothes. The only reason vegans are able to deny this is because they are pretending that the people who had to suffer for their ideology don't exist.
  
• Vegans are not raising enough awareness about deficiencies and as a result harm innocent children. B12 deficiency can cause irreversible nerve damage, psychosis and is hard to notice. 10-50% of vegans say they don't even take any supplements.
  
• Vegan diets are more dependent on slavery because they rely on global food supply. Many crops, especially cotton, nuts, oils and seeds that they have to include in higher quantities to make up for animal products are to a large extent child labor products from developing countries. 108 million children work in agriculture. Cheese replacements (guess who's responsible for that) are usually made with cashews, which burn the fingers of the women who have to remove the shells. A larger list of examples can be found here.
  
• Vegans have never been able to define or measure that their diet causes less deaths/suffering than an omnivorous one. They are ignorantly contributing to an absolute bloodbath of trillions of zooplankton, mites, worms, crickets, grasshoppers, snails, frogs, turtles, rats, squirrels, possum, raccoons, moles, rabbits, boars, deer, 75% of insect biomass, half of all bird species and 20,000 humans per year. Two grass-fed cows are enough to feed someone for a year and, if managed properly, can restore biodiversity. The textbook vegan excuse where they try to blame plant agriculture on animals and use only mice deaths, fabricated feed conversion ratios of 20:1 and a coincidentally favourable per-calorie metric is nonsense because:
  
  1. The majority of animal feed is either low-maintenance forage or a by-product that only exists because of human food harvest.
  2. It literally shows that grass-fed beef kills fewer animals.
• Vegans likely exploit more animals than the average person. The Vegan Society officially rejects beekeeping, but many commercial crops require to be pollinated by domestic bees that are forced to breed, shipped around and then worked to death. It's principally impossible to have a nutritionally complete vegan diet without forced pollination, but fodder crops do not exploit bees. As a result, human food crops kill five times as many bees as all livestock slaughter combined and directly support honey production (taking excess honey is necessary for colony health). Vegans should also call around and make sure that their seasonally changing food exporters don't rely on insects, terriers, sheep, ducks, organic fertilizers or anything from developing countries where animal labor is still common.
  
• The ethical framework around veganism (negative utilitarianism) is so insane that its logical conclusion is to prevent as much life and biodiversity as possible in order to reduce suffering, which means it also favors Brazilian rainforest beef over crop cultivation. This line of thought is already followed by organizations like PETA who proudly state it to be their goal and will steal and euthanize other people's pets. Vegans reject appeals to nature when they are used to defend omnivorism, yet falsely assume that animals are more happy under the stress of natural selection. In contrast to livestock, wild animals are never guaranteed to receive shelter, protection, food, medical care, low stress or a quick death. Animal rights conflict with welfare because their goal is not to increase happiness, but just to oppose animal husbandry. Put differently, vegans pretend to support the wellbeing of animals, but can hardly even do so with their consumer power. What they are doing is more likely to kill off local ranchers and ensure a monopoly for Tyson/JBS, who are spearheading fake meat btw.
  
• The average vegan is, based on their demographic, a New York hipster that has never seen a farm in their live. Animals are not being abused (This is one of the "factory farms" where 99% of animals come from). Undercover videos have often been staged by agenda-driven activists who get paid to apply for farm jobs and encourage animal abuse. The real industry has government-inspected welfare regulations. (Dominion straight up lies about pigs in slaugherhouses getting no water - it's required by law). Here's some actual industrial slaughterhouse footage of Beef, Turkey and Pork. For comparison, rodenticides are intentionally made to drain the life out of rats over three days so that they can't figure out what killed them.
  
• Vegans love to misportray farm practises and anthropomorphize animals by giving them concepts that they don't care about, or even enjoy. Sexual coercion ("rape") is normal procreation and cows don't see a problem with it. They will even milk themselves when given the possibility. Pigs don't mind eating their own babies or getting shot. Even the myth that they are as intelligent as dogs comes from a questionable study made by animal rights advocates.
  
• The reputation of vegans is based exactly on how they present themselves in public. Humans evolved to have predatory behaviour and as a result many people enjoy homesteading, hunting or fishing. Vegan activists frequently bother society and disrespect human biology - with thousands of years of history - for their arbitrarily chosen set of morals. There are actual animal rights terrorist groups that have sent bombs and stalked children, which they justify with it being done "in the name of veganism". Therefore, a very good reason to stay away from veganism is simply because someone doesn't want to be associated with a cult-like ideology.
  

Philosophy

• The definition that vegans pride themselves with is a laughing stock because not only is it so loosely defined that it can be used to call everyone vegan, but it also shamelessly co-opts all the belief systems that have existed for much longer. According to this definition, Hindu, Buddhists, the Inuit and carnivores can all be called vegan, but are not following the diet and therefore considered impure (apparently caring about animals was invented by some British guy in 1944). Vegans are nothing more than people who abstain from animal products, in fact veganism was originally defined as a diet.
  
• The misanthropic idea of "speciecism" was popularized by a nutjob philosopher who argues in favour of bestiality and belittles disabled people, but makes exceptions when it affects himself. Ironically, he eats animal products and calls consistent veganism fanatical. When it comes to the misanthropic aspect, animal rights activists themselves are the best example because they frequently insult minorities and crime victims by equating them to livestock with analogies to rape, murder, slavery or holocaust. The best part is that vegans are speciecists themselves because they justify their killing as "necessary for human survival" and still won't equate a cow to an insect.
  
• Since vegans somehow manage to justify systematically poisoning and torturing insects by arbitrarily declaring that they can't suffer ("sentience"), they might aswell consider eating them. The same goes for bivalves, since there's about as much evidence that they feel pain as there is for plants.
  
• A vegan diet itself is not even vegan under its own premises because it's not "practicable" to follow. It demands an opportunity cost of time, research and money that could be utilized in a better way and even then is not guaranteed to be efficient because it emphasizes purity. The entire following around veganism represents a Nirvana Fallacy and is the reason why the majority of people quit: Perfect is the enemy of good. A vegan diet makes it harder, and for many people impossible, to follow productive consumer approaches such as buying local, seasonal or supporting regenerative agriculture.
  

List of known nutrients that vegan diets either can't get at all or are typically low in, especially when uninformed and for people with special needs. Vegans will always say that "you can get X nutrient from Y specific source", but a full meal plan with sufficient quantities will essentially highlight how absurd a "well-planned" vegan diet is.

1. Vitamin B12
2. Vitamin B6 (Pyridoxal, Pyridoxamine)
3. Choline
4. Niacin (bio availability)
5. Vitamin B2
6. Vitamin A (Retinol, variable Carotene conversion)
7. Vitamin D3 (winter, northern latitudes, synthesis requires cholesterol)
8. Vitamin K2 MK-4 (variable K1 conversion)
9. Omega-3 (EPA/DHA; conversion from ALA is inefficient, limited, variable, inhibited by LA and insufficient for pregnancy)
10. Iron (bio availability)
11. Zinc (bio availability)
12. Calcium
13. Selenium
14. Iodine
15. Protein (per calorie, digestibility, Lysine, Leucine, elderly people, athletes)
16. Creatine (conditionally essential)
17. Carnitine (conditionally essential)
18. Carnosine
19. Taurine (conditionally essential)
20. CoQ10
21. Conjugated linoleic acid
22. Cholesterol
23. Arachidonic Acid (conditionally essential)
24. Glycine (conditionally essential)

Common vegan debate tactics/fallacies:

• Nirvana fallacy: "There's no point in eating animal products because everything can be solved with a perfect vegan diet, supplements and genetic predisposition."
  
• Proof by example: "Some people say they are vegan. Therefore, animal products are unnecessary."
  
• Appeal to authority: Pointing to opinion papers written by vegan shills as proof that their diet is adequate.
  
• No true Scotsman: "Everyone who failed veganism didn't do enough research. Properly planned vegan diets are healthy!" (aka not real Socialism)
  
• Narcissist's prayer: "Everything bad that came out of veganism is fault of the world, not veganism itself."
  
• No true Scotsman: "Veganism is not a diet, it's an ethical philosophy. No true vegan eats almonds, avocados or bananas ..."
  
• Definist fallacy: "... as far as is possible and practicable." (Can be used to defend any case of hypocrisy)
  
• Special pleading: "It's never ethical to harm animals for food, except when we 'accidentally' hire planes to rain poison from the sky." (You can trigger their cognitive dissonance by pointing that out.)
  
• Special pleading: "Anyone who doesn't agree with my ideology has cognitive dissonance."
  
• Appeal to emotion: Usage of words exclusive to humans (rape, murder, slavery, ... ) in the context of animals.
  
• Fallacy fallacy: "Evolution is a fallacy because it's natural."
  
• Texas sharpshooter fallacy: "A third of grains are fed to livestock. Therefore, a third of all crops are grown as animal feed."
  
• False dilemma: "Producing only livestock is less sustainable than producing only crops, so we should only produce crops."
  
• False cause: Asserting that association infers causation because it's the best data they have. ("Let's get rid of firefighters because they correlate to forest fires")
  
• Faulty generalization: Highlighting mediocre athletes to refute the fact that vegans are underrepresented in elite sports.
  
• JAQing off: This is how vegans convert other people. They always want them to justify eating meat by asking tons of loaded questions, presumably because nobody would care about their logically inconsistent arguments otherwise. Cults often employ this tactic to recruit new members. (They mistakenly call it the Socratic method)
  
• Argument from ignorance: NameTheTrait aka "vegans are right unless you prove their nonsensical premises wrong". (It's essentially asking "When is a human not a human?")
  
• Moving the goalposts: Whenever a vegan is cornered, they will dodge and change the subject to one of their other pillars (Ethics, Health, Environment or Sustainability) as seen here.
  
• Ad hominem: Nit-picking statements out of context, attacking them in an arrogant manner, and then proclaiming everything someone says is wrong while not being able to refute the actual point. (see Kresser vs Wilks debate)
  

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Disclaimer

I am not a doctor! Please don’t sue me, I’m already poor!
 

Lesson 1.6.1: The Acid Mantle

 
Welcome back, lovelies! Today, I will finally be delivering on the topic I have been unintentionally postponing for the past who-knows-how-long:
 
*: ͓ °✧ the acid mantle ✧° ͓ : *
 
But did you notice that pesky “.1” stuck in the title? You guessed it -- this subject is getting at least one more post all to itself.
So for now, we’ll be focusing our attention on the substances responsible for making the acid mantle, and the glands responsible for making these substances!
 
Prerequisites:

• 1.1 - Layers of the Skin
• 1.2.1 - Skin Cells - Function, Structure & Protein Babies
• 1.2.2 - Skin Cells - Hypodermal Specialized Cells (not required, but recommended)
• 1.2.4 - Skin Cells - Epidermal Specialized Cells, pt. 2 (not required, but recommended)
• 1.4 - Acids and Bases
• 1.5 - The pH Scale

 

What Is The Acid Mantle?

 
The surface of your skin is acidic, and it has something to do with sweat. That was about as much as we knew on this topic back in 1892, when it was first brought up in a published paper.
Luckily, along came 1928, when German dermatologist Alfred Marchionini and his teacher, H. Shade, published a paper that gave us a better description of this thing they called the “säuremantel”, an acidic film on the surface of the skin that discouraged the growth of bacteria.
With this slightly newer paper unveiling the potential relationship between skin acidity and your overall health, it paved the way for scientists to give more of a crap and start studying it a bit more closely.
We now lovingly refer to this film as the acid mantle.
 
When you are first born, the pH of your acid mantle isn’t all that acidic, measuring in at about 6.4. It’s not until your third or fourth day of existence that the pH will drop down to about 4.9.
Now that you’re older, it probably still has an acidic pH, measuring somewhere between 4.0 and 5.9. That low pH is what gives this film a starring role in your innate immune system, as it is your body’s first line of defense against pathogens.
 
But while acting as your skin’s bacterial bouncer might be the role your acid mantle is most famous for, don’t start typecasting this guy -- your acid mantle has a fantastic resume:

• It works as a barrier, being one of the many tools your skin uses to prevent water from escaping (because we all know that skin likes to be a moisture hog).
• It plays a heavy supporting role in making sure your lipid barrier is in tip top shape.
• And it helps to protect you against the damage caused by free radicals.

 
In today’s lesson, we’ll just be focusing on the junk that forms the acid mantle. But keep these jobs in mind because next time, we will be learning about how your mantle actually performs all of these tasks.
 

Eccrine Sweat Glands

 
It feels like we’ve come a long way since the last time we talked about integumentary accessory structures. ^{Aw, I should start scrapbooking about how far we’ve come. ♡}
But now that three of these structures have finally landed a starring role in our lesson, it’s about time we give them more than just a couple of wimpy little paragraphs, don’t you think?
 
As you might remember, your sweat glands come in two flavors: eccrine and apocrine.
Eccrine glands are the type you are most familiar with, as they are the type that adorn your face and the majority of your body. These are also the ones I mentioned in our first lesson that look like knotted spaghetti noodles in your dermis that reach up to the top of your epidermis.
 
Fig. 1, Eccrine Gland Drawing
 
Fig. 2, Eccrine Gland Microscope Slide
 
The knotted portion is called the secretory coil, and is actually a cul-de-sac -- it doesn’t have an input, just an output. The input is actually handled by the cells that line the inside of the coil, which secrete the sweat into the gland. Some of the cells here can contract as well, which is what pushes the perspiration out of the noodle instead of letting it just...sit there.
The noodly portion is known as the sweat duct. The cells here will reabsorb some of the electrolytes in the sweat that had previously been secreted into the coil, leaving your sweat just slightly less salty than it would've been.
The purpose of sweating from these glands is to help regulate body temperature. When you sweat, the cool substance sits on your warm skin’s surface, which helps it to cool down.
The sweat that comes from these glands has a pH between 4.0 and 4.5, and is near 99% water, with the remaining 1% being a cocktail of urea, lactate, sodium, chloride, and potassium.
 

Urea

Urea might sound similar to another word you know...urine! That’s because urea is the byproduct of cellular waste, so the body needs to get rid of it by peeing or sweating it out.
Its chemical formula is CH₄N₂O, which means it has two NH₂ groups joined by a carbonyl group (which is just a carbon that’s double-bonded to an oxygen), like this:
 
Fig. 3, Urea
^{You don’t see a C for carbon in this picture because it’s assumed that the pointy part of the V shape that’s connecting the two N’s is the carbon. The = connecting that point to the O is the double-bond.}
 
Maybe NH₂ sounds a little familiar as well. Perhaps you’re thinking of NH₃ from our acid and base lesson, which is the chemical formula for ammonia. Well, funnily enough, urea is made when your liver breaks down ammonia!
Ammonia is produced by the cellular breakdown of amino acids, but as you know, ammonia is kind of a dangerous chemical. So your liver handles all this junk by consuming two ammonia molecules and one carbon dioxide (CO₂) molecule, then converting them into urea. Makes sense when you see urea happens to contain all of the elements that make NH₃ and CO₂, doesn’t it?
 

Lactate

No, it has nothing to do with nursing a baby. Lactate production is the result exercising!
So, you breathe, right? ^{Cool, me too!} Breathing is your body’s preferred way of creating energy, because the oxygen you’re bringing in is super convenient for your cells to access. When your cells use oxygen to create energy, it is called aerobic respiration.
 
Fun Fact: This is where aerobic exercise gets its name from! Aerobic exercises, like walking, jogging, swimming, and cycling, get you breathing more. This heightened level of oxygen input is being used by your cells to quickly produce the energy they need to keep up with the workout, so you can continue to walk, jog, swim, or cycle for prolonged periods of time.
 
But when you engage in a much more strenuous activity, like when you decide to pump some iron instead of hitting the treadmill, your cells end up needing to produce energy faster than the rate at which they’re receiving oxygen. When this happens, they’ll substitute the oxygen in their energy recipe for a different ingredient -- glucose (sugar). When your cells use something other than oxygen to produce energy, it’s known as anaerobic respiration. (And strength training is a type of anaerobic exercise. While you might be able to jog for an hour, you certainly couldn’t do bicep curls for an hour.)
The glucose is broken down by your cells into something called pyruvate. The pyruvate is then converted into lactate, and that lactate allows your cells to continue breaking down glucose while you’re still exercising.
 
By the way, if you are a brethren of /swoleacceptance, you might come across the occasional fitness article using lactic acid interchangeably with lactate. (And if you aren’t praising Brodin, you might recognize it as an AHA!)
So let me clarify that lactate is not the same thing as lactic acid. Your body does not make lactic acid, it makes lactate.
They are definitely related, though! Lactate is the conjugate base of lactic acid, and if you were paying attention during lesson 1.4, you’ll know that this means lactate is the chemical result of lactic acid that has dissociated and lost an H⁺. So go ahead and slap someone with knowledge the next time you visit the bodybuilders forum! ^{Don’t do this in person, though. I wouldn’t want you to be on the receiving end of some roid rage.}
 

Sodium, Chloride, and Potassium

Why did I lump these three together? Because they are all electrolytes. Electrolytes are named such because they are minerals that are either positive or negative ions, giving them an electrical charge.
Sodium regulates the amount of water in your body, and it is required to help generate the electrical signals that allow your various bodily processes to talk to each other (like when your nervous system is talking to your brain about how it didn’t like when you touched the stove). Potassium regulates heartbeat and muscle function -- too much or too little potassium can result in an irregular heartbeat, which can be fatal. Chloride maintains the balance of body fluids.
Electrolytes are clearly all very important, which is why Gatorade is so good at making you feel better after you’ve run a mile and were sweating out your electrolytes, or you’ve been sick and were vomiting up all your electrolytes.
 

Apocrine Sweat Glands

 
I haven’t given these glands very many words before because they aren’t found on your face, preferring only to hang out in all the spots that get hairy during middle school -- in your armpits and in your downstairs mixup. However, since your acid mantle is kind of all over your body, I feel like you guys deserve to know how these glands might affect it.
While these glands also look like spaghetti noodles, they’re a bit larger (so maybe more like worms?), and their noodly portion leads to a hair follicle rather than the skin’s surface. The apocrine sweat empties into the follicle, where it then empties out onto the surface.
 
Fig. 4, Apocrine Sweat Gland
 
(Couldn’t find a satisfactory microscope slide. Sorry!)
 
These glands use the same structural names as their cousins do -- the knotted bit is the secretory coil and the noodly bit is the sweat duct.
 
Fun Fact: While the apocrine glands we’re discussing today are only found in the hairy forests of your body’s landscape, some special, modified versions of these glands than can be found in other areas. There’s some in your nipples that can feed your babies, some in your eyelids that help with killing off bacteria, and some in your ears that make ear wax!
 
The sweat from these glands isn’t very effective at regulating your body temperature because the chemical composition is a little more lipid-y than eccrine sweat (and since these glands aren’t on your face, I won’t bother with a chemical breakdown here).
This sweat also as a more neutral pH, between 6 and 7.5, meaning your mantle isn’t very acidy in your pits. Between the lipidiness and the neutral pH, this sweat will forever leave you in dire need of some deodorant.
Sweat does not stink.
But bacteria, much like humans, enjoy munching on fat way more than they like munching on salty, pee-flavored water. They also thrive in more basic environments. The stink comes from the bacteria tootin’ up a storm while feasting on your armpit buffet. ^{Man, I am just full of beautiful imagery today.}
 
If your apocrine sweat doesn’t do any thermoregulating, then why are you cursed with these glands?!
Well, these glands are actually a throwback to your ancient ancestors, with the sweat functioning as a territorial marker (if it smells like you, it’s probably yours), as a warning signal (humans don’t get eaten when they smell gross, I guess), and as a pheromone (only baby-making humans smell like that ;D).
Due to the type of jobs that this sweat is meant for, it makes sense that these glands are activated by hormones rather than temperature. This means they don’t end up getting used until you’ve hit puberty and nature has deemed you old enough to need this kind of sweat. And because they are hormone-activated, this also means that these are the glands that are sweating whenever you are emotionally distraught. (Thanks, guys, for making the pits of my t-shirt wet during all of my high school book report presentations. You really know how to help out.)
 

Sebaceous Glands

 
You should know these guys pretty well by now. Not only have we discussed them before, but they are usually blamed as the source of your skincare woes. To be fair...they often deserve the blame. But with sebum carrying a pH between 4.5 and 5.5, these guys are often under-appreciated for their efforts in the fight against baddies.
 
Fig. 5, Sebaceous Gland
 
Fig. 6, Sebaceous Gland Microscope Slide
 
You might have also noticed in Fig. 6 that the follicle shown has two glands, but it's common for follicles to only have one gland hanging out nearby. They like being attached because, just like apocrine glands, they can deposit their sebum into the follicle, where it then flows out of the pore and onto the skin. The whole enchilada of a follicle paired with a sebaceous gland is known as a pilosebaceous unit.
 
Fun Fact: Some sebaceous glands do open up directly to the skin’s surface. These can be found as little bumps inside your cheeks, on your areolae, and near or on your nono-zone! (I would include pictures, but they’re all NSFW. D:)
 
The gland itself is an outgrowth of the follicle’s sheath, and it is filled with a special little cell called a sebocyte, which is the guy who actually makes the sebum.
You know by now how most cells go about delivering their products, right? They usually make a protein baby, and then poop it out of the cell membrane.
Glands with cells that deliver their junk in this manner are known as merocrine glands, and your eccrine sweat glands are an example of this type.
 
Fig. 7, Merocrine Gland Secretion
 
Some glands produce stuff that’s a little too thick to just poop out; you can think of them as needing some Metamucil. In order to deliver their junk, their cells need to wrap the secretion up in some of their cytosol and cell membrane before just severing the whole package. It sounds painful, but they manage to recuperate just fine.
Glands that specialize in this type of delivery are known as apocrine glands, and unsurprisingly enough, a great example of this type would be your apocrine sweat glands.
 
Fig. 8, Apocrine Gland Secretion
 
Well, our little sebocyte here likes to do things a bit differently. His junk is a lot thicker than the stuff other cells are making; thick enough that it makes him crazy constipated. In fact, he is so constipated that he will end up exploding in the process of trying to poop it all out. ^Gasp!
Glands whose cells will end up exploding in order to deliver junk are known as holocrine glands. Sebaceous glands are the only holocrine glands found on the human body.
 
Fig. 9, Holocrine Gland Secretion
 
Now that you know sebum is thick enough to make a cell explode, you might be wondering wtf is in this crap. Well, it’s even more lipidy than your apocrine sweat. In fact, its composition is 100% lipid, made up of triglycerides, free fatty acids, wax esters, squalene, cholesterol, and cholesterol esters.
 

Triglycerides

You might recognize this guy from our lesson on the hypodermis. This is the type of lipid that gets stored in your lipocytes, and the stuff you’re trying to get rid of when you start a new diet. This stuff composes the majority of your sebum, making up around 30-50% of it.
The official definition: A triglyceride is an ester of fatty acids and glycerol. In fact, they are sometimes referred to as esters of glycerol.
 
Okay, but what does this mean?
From “tri”, we can guess there is a triplet of some sort. This triplet just so happens to be three chains of fatty acids (more on these in the next section). Any fatty acid will do; some triglycerides have three of a kind, and some could have three totally different fatty acids.
The “glyceride” tells us that these fatty acids are all held together by a glycerol compound (also known as glycerin -- sound familiar?).
 
Fig. 10, Triglyceride Chemical Structure
 
In this picture, the red portion is our glycerol, and the black chains are our three fatty acids. The C’s in those chains are for carbon, and the lines drawn between them actually represent hydrogen molecules that are binding them together. (If you see a zig-zag without C’s, each point of the chain will almost always represent carbon, kind of like back in Fig. 3.)
So what exactly is an ester? It’s an organic compound (meaning, any chemical compound that contains carbon) made by replacing the hydrogen of an acid with a hydrocarbon group (a compound of hydrogen and carbon).
In triglycerides, our hydrocarbon group comes from the glycerol.
 
Fig. 11, Glycerol
 
Now, let’s attach our fatty acids to form an ester. We’ll use stearic acid (CH₃(CH₂)₁₆COOH) as all three of our fatty acids.
 
Fig. 12, Glyceryl Tristearate
 
Oh my...did you notice our stearic acids don’t end in -COOH like I had just said? They end in -COOCH! ^heh. This is because the hydrogen of our acids were replaced by the glycerol’s hydrocarbon group, a CH. By combining glycerol and three stearic acids, we’ve made glyceryl tristearate, a triglyceride!
 

Free Fatty Acids

Free fatty acids are exactly the same as the fatty acids we discussed above. They’re called “free” because these fatty acids aren’t being used to make any triglycerides, so they are unattached. They make up 15-30% of your sebum.
A fatty acid is an organic compound that contains a carboxyl group (that -COOH we mentioned earlier) and has a long chain of carbons and hydrogens trailing behind it, and the length of that chain can vary anywhere from 10 to 30 carbons (stearic acid had 18, by the way!).
Most of the fatty acids in your sebum tend to be unsaturated. This means that, somewhere along their chain, there is a spot where a carbon atom is bound directly to the next carbon in the chain, instead of every carbon being held together by hydrogen. To help you remember this, think of saturated fats as having a chain that’s fully saturated with hydrogen atoms.
 
Fig. 13, Saturated vs. Unsaturated
 
Saturated fats are solid at room temperature (e.g. butter), whereas unsaturated fats are liquid at room temperature (e.g. oil). This is why your sebum is oily rather than little beads of butter popping out of your pores. This also means you won’t be finding the saturated stearic acid in your sebum, but you will find sapienic acid, sebaleic acid, and linoleic acid, among others.
 
Sapienic acid is the predominant fatty acid in sebum. It gets its name from homo sapiens, because it is really difficult to find this fatty acid anywhere else in nature other than in human sebum. Some studies suggest that this stuff is the big hitter in killing off the bacteria responsible for acne, yet other studies suggest that people with acne have higher levels of sapienic acid than those without acne. In other words, science has yet to figure out what this crap actually does.
Sebaleic acid is pretty similar to sapienic acid, just with two extra carbons. It’s also similar in that it is only found in human sebum, and that it is depressingly understudied. :(
Linoleic acid is used by sebocytes to produce squalene, and the sebum of acne sufferers tends to have lower levels of linoleic acid and higher levels of squalene present. But we’ll get to that more in a minute. (Fun Fact: Linoleic acid isn’t naturally produced by the body, so it needs to come from your diet! You can find it in olive oil.)
 
The exact amount of each fatty acid, free or otherwise, that can be found in sebum will differ from person to person. But it’s worth noting that, while an acne-sufferer tends to produce more sebum than an acne-free person, if you were to take a sample the same amount of sebum from both types of people, the person with acne would actually have 53% fewer free fatty acids of any kind present.
 

Wax Esters

Wax esters make up 26-30% of your sebum. While not unique to humans, they are unique to sebum, as they aren’t produced anywhere else in the body.
Heyyy, weren’t we just talking about esters?! Why, yes!
So we know that triglycerides are an ester of fatty acids and glycerol. Well, wax esters are an ester of a fatty acid and a long-chain alcohol, with the alcohol’s chain being anywhere from 12 to 32 carbons long. Knowing how long fatty acids are, you can tell wax esters are really long.
 
Fig. 14, Wax Ester
 
Now, glycerol is an alcohol. But it doesn’t have a long chain, so triglycerides aren’t considered to also be wax esters. Also, they are triglycerides -- wax esters only have one fatty acid attached to an alcohol.
 
You might see “wax,” and start thinking of candles, Burt’s Bees, or Vaseline (which is actually a mix of wax and oil, by the way). While not all waxes are esters, they do all sort of function in the same waxy way. They seem to be even more water-resistant than oils and fats, and they are fantastic for lubricating and sealing in moisture. This is exactly what the wax esters in your sebum do -- they waterproof your skin, smooth it out, and try to lock in moisture.
The production of wax esters also seems to be related to helping sebocytes level up to the point where they are ready to do their exploding thing. While research has yet to uncover what exactly this relationship is, it has been shown that sebaceous glands tend to waste away when wax esters aren’t getting made properly. These guys do require a lot more studying in the future. (Isn’t it amazing how much we still don’t know about the human body here in the 21st century?)
 

Squalene

This one makes up 12-20% of your sebum, and it is yet another product that is kinda unique to sebum. (Fun Fact: Squalene gets its name from where it was first discovered -- in the liver of Squalidae, or dogfish sharks.)
 
When your body needs to produce a specific chemical, it’s a multi-stage process, with each stage involving a few steps. Think of it as baking a cake. The first stage requires filling a mixing bowl with dry ingredients. But to complete this stage, it has to go through the steps of measuring out, sifting, and adding the flour, baking powder, and salt.
To make cholesterol, the first stage is to make mevalonate. In order to complete this stage, your body needs to take the steps of measuring out three acetyl-CoA’s, then combining them. Stage two is to make isopentenyl pyrophosphate (don’t worry, you don’t need to remember that). And stage three is to make squalene.
 
Normally, the body uses squalene to carry out the fourth and final stage of producing cholesterol. But for some reason, your sebaceous glands are the only places in your body that prefer to halt production at stage three, leaving your sebum with way more squalene than cholesterol. While research has yet to come up with an answer as to why this happens, all we know is that it does, indeed, happen.
There is a theory, however, that the preference for squalene over cholesterol in sebum might be the evolutionary result of pollution. In other words, human sebaceous glands evolved to start making squalene in order to upgrade their skin protection in the face of an increasingly polluted environment.
Such an interesting theory makes it sound like squalene might do something really cool, right? Well, as it turns out, squalene is pretty cool.
See, when squalene is exposed to UV radiation, it begins to gobble up oxygen as an attempt to protect the skin from receiving the full force of the sun. If that doesn’t sound at all cool, don’t worry; we’ll be getting way more in depth about this in the next lesson.
 
Unfortunately, when squalene eats up oxygen, it results in squalene peroxide.
While squalene itself is not harmful to your skin, squalene peroxide definitely is. Your sebum will attempt to make up for the crappy side effects of squalene peroxide by additionally dumping a bunch of vitamin E onto your skin, but the good intentions don’t always cut it. Expect us to be digging into squalene peroxide a lot more in the acne section.
 

Cholesterol and Cholesterol Esters

Cholesterol and its esters make up only a measly 4.5% of your sebum. You can probably guess that the reason for this is because of the preference for squalene.
While cholesterol in cosmetics is used for its moisturizing properties, I honestly couldn’t find much information on the purpose of cholesterol in sebum. This lack of information leads me to believe this is because such an abnormally tiny amount of cholesterol might be viewed as sort of a byproduct of all the squalene production, rather than an “active ingredient,” so to speak. (But that’s just my take on it, so don’t quote that as a fact!)
 
 
That’s it for today, my dears! This lesson is already, like, five pages longer than I prefer them to be. ^{To be fair, I’m not exactly known for brevity. ;3;} I hope you’re ready to get slapped with even more säuremantel knowledge next time; my fingers are already itching to get started!
 
ѧѦ ѧ ︵͡︵ ̢ ̱ ̧̱ι̵̱̊ι̶̨̱ ̶̱ ︵ Ѧѧ ︵͡ ︵ ѧ Ѧ ̵̗̊o̵̖ ︵ ѦѦ ѧ ︵͡︵ ̢ ̱ ̧̱ι̵̱̊ι̶̨̱ ̶̱ ︵ Ѧѧ ︵͡ ︵ ѧ Ѧ ̵̗̊o̵̖ ︵ ѧѦ ѧ
 
Hello, everyone!
I hope you weren’t too disappointed by today’s lesson. I know the wait has been long, and I really wanted to squish all of the acid mantle stuff into one lesson, but my character count has forced me to split this subject in two. I’m worried you’re all getting pretty sick of these super science-heavy lessons, since it might not seem immediately clear how any of this info is relevant to managing a skincare issue.
But hopefully you guys will bear with me and just trust that this will all make sense in the end! I really appreciate all of you for sticking around and reading my walls of science text. ♡ Thank you for reading, and leave any questions below. :)
 

• Please Note:
  There was a lot of info I left out of the section on lactate, like the fact that triglycerides can also be used in anaerobic respiration, or that lactate has nothing to do with post-workout muscle aches. I also left out a lot of chemistry-related info regarding saturated/unsaturated fats and wax esters.
  I did this because I figured these tangents would take us unnecessarily off topic, but if you would like to know more about rest-of-the-body biology or chemistry, feel free to ask about it in the comments or send me an email if you’re on the mailing list. Because, as much as I would enjoy going more in depth on human body biology in a lesson, that’s not really a topic relevant to this subreddit, haha.
  

 
Sources:
http://link.springer.com/article/10.1007/BF00412626 http://www.ncbi.nlm.nih.gov/pubmed/12964343?dopt=Abstract http://emjreviews.com/wp-content/uploads/Skin-pH-in-the-Elderly-and-Appropriate-Skin-Care.pdf [PDF] http://www.gastrohep.com/ebooks/rodes/Rodes_2_3_7.pdf [PDF] http://www.scientificamerican.com/article/why-does-lactic-acid-buil/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835892/ http://www.ncbi.nlm.nih.gov/pubmed/19944183 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835893/ http://chemwiki.ucdavis.edu/Core/Organic_Chemistry/Esters/Properties_of_Esters http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835908/ http://www.ncbi.nlm.nih.gov/pubmed/2936775 http://www.ncbi.nlm.nih.gov/pubmed/12787115 http://www.ncbi.nlm.nih.gov/pubmed/6481825 http://www.jbc.org/content/97/2/433.full.pdf [PDF]

Organisms of many species are specialized into male and female varieties, each known as a sex.[1] Sexual reproduction involves the combining and mixing of genetic traits: specialized cells known as gametes combine to form offspring that inherit traits from each parent. Gametes can be identical in form and function (known as isogamy), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist (known as anisogamy). By definition, male gametes are small, motile, and optimized to transport their genetic information over a distance, while female gametes are large, non-motile and contain the nutrients necessary for the early development of the young organism. Among humans and other mammals, males typically carry XY chromosomes, whereas females typically carry XX chromosomes, which are a part of the XY sex-determination system.
The gametes produced by an organism determine its sex: males produce male gametes (spermatozoa, or sperm, in animals; pollen in plants) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic. Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience.
Contents [hide] 1 Evolution 2 Sexual reproduction 2.1 Animals 2.2 Plants 2.3 Fungi 3 Sex determination 3.1 Genetic 3.2 Nongenetic 4 Sexual dimorphism 5 See also 6 References 7 Further reading 8 External links Evolution
Main article: Evolution of sexual reproduction It is considered that sexual reproduction in eukaryotes first appeared about a billion years ago and evolved within ancestral single-celled eukaryotes.[2] The reason for the initial evolution of sex, and the reason(s) it has survived to the present, are still matters of debate. Some of the many plausible theories for the appearance of sexual reproduction include: the creation of variation among offspring, to spread advantageous traits, the beneficial removal of disadvantageous traits, and that sex evolved as an adaptation for repairing damage in DNA. (See the evolution of sexual reproduction.)
While there are a number of theories, there are two main alternative views on the evolutionary origin and adaptive significance of sex. The first view assumes that sexual reproduction is a process specific to eukaryotes, organisms whose cells contain a nucleus and mitochondria. In addition to sex in animals, plants, and fungi, there are other eukaryotes (e.g. the malaria parasite) that also engage in sexual reproduction. On this first view, the adaptive advantage that maintains sexual reproduction (in competition with asexual modes of reproduction) is the benefit of generating genetic variation among progeny. Furthermore, on this view, sex originated in a eukaryotic lineage. The earliest eukaryotes and the bacterial ancestors from which they arose are assumed to have lacked sex. For instance, some bacteria use conjugation to transfer genetic material between cells; and while not the same as sexual reproduction, this also results in the mixture of genetic traits. The reason that bacterial conjugation is not the same as sexual reproduction is that the numerous genes necessary for conjugation are not located on the bacterial chromosome, but on small circular DNA self-replicating parasitic elements called conjugative plasmids. Thus, conjugation arises from an adaptation of parasitic DNA for its own transmission.[3]
The second alternative view on the evolutionary origin and adaptive significance of sex is that sex existed in early bacteria as the process of natural transformation, a well studied DNA exchange process still in existence in many present day bacterial species (see Transformation (genetics)). Transformation involves the transfer of DNA from a donor to a recipient bacterium. Recipient bacteria must first enter a special physiological state, termed competence, to receive donor DNA (see Natural competence). The numerous genes necessary for establishment of competence are located on the bacterial chromosome itself. Thus the process of transformation is likely beneficial to bacteria, and can be regarded as a simple form of sex. In general, competence is induced under stressful conditions, such as nutrient limitation and exposure to DNA damaging agents, as reviewed by a number of authors.[4][5][6] Sex, on this view, was present in the earliest single-celled eukaryotes because they were descended from ancestral bacteria capable of transformation. Sex was maintained as an adaptation for repairing DNA damage (see Evolution of sexual reproduction). In particular, meiosis the key stage of the sexual cycle of eukaryotes, in which genetic information derived from different individuals (parents) recombines, was likely derived from the analogous, but simpler, genetic information exchange and DNA repair process that occurs during transformation in bacteria[7][8][9][10] (and also see Meiosis, section: Origin and function of meiosis). Thus, by this view, sex appears to have evolved in bacteria as a way of repairing DNA damages induced by environmental stresses, was maintained through the prokaryote/eukaryote boundary, and continued to evolve in higher multicellular eukaryotes, in part, as a DNA repair process.
What is considered defining of sexual reproduction in eukaryotes is the difference between the gametes and the binary nature of fertilization. Multiplicity of gamete types within a species would still be considered a form of sexual reproduction. However, no third gamete is known in multicellular animals.[11][12][13]
While the evolution of sex itself dates to the prokaryote or early eukaryote stage, the origin of chromosomal sex determination may have been fairly early in eukaryotes. The ZW sex-determination system is shared by birds, some fish and some crustaceans. Most mammals, but also some insects (Drosophila) and plants (Ginkgo) use XY sex-determination. X0 sex-determination is found in certain insects.
No genes are shared between the avian ZW and mammal XY chromosomes,[14] and from a comparison between chicken and human, the Z chromosome appeared similar to the autosomal chromosome 9 in human, rather than X or Y, suggesting that the ZW and XY sex-determination systems do not share an origin, but that the sex chromosomes are derived from autosomal chromosomes of the common ancestor of birds and mammals. A paper from 2004 compared the chicken Z chromosome with platypus X chromosomes and suggested that the two systems are related.[15]
Sexual reproduction
Main article: Sexual reproduction Further information: Isogamy and Anisogamy
The life cycle of sexually reproducing organisms cycles through haploid and diploid stages Sexual reproduction in eukaryotes is a process whereby organisms form offspring that combine genetic traits from both parents. Chromosomes are passed on from one generation to the next in this process. Each cell in the offspring has half the chromosomes of the mother and half of the father.[16] Genetic traits are contained within the deoxyribonucleic acid (DNA) of chromosomes—by combining one of each type of chromosomes from each parent, an organism is formed containing a doubled set of chromosomes. This double-chromosome stage is called "diploid", while the single-chromosome stage is "haploid". Diploid organisms can, in turn, form haploid cells (gametes) that randomly contain one of each of the chromosome pairs, via meiosis.[17] Meiosis also involves a stage of chromosomal crossover, in which regions of DNA are exchanged between matched types of chromosomes, to form a new pair of mixed chromosomes. Crossing over and fertilization (the recombining of single sets of chromosomes to make a new diploid) result in the new organism containing a different set of genetic traits from either parent.
In many organisms, the haploid stage has been reduced to just gametes specialized to recombine and form a new diploid organism; in others, the gametes are capable of undergoing cell division to produce multicellular haploid organisms. In either case, gametes may be externally similar, particularly in size (isogamy), or may have evolved an asymmetry such that the gametes are different in size and other aspects (anisogamy).[18] By convention, the larger gamete (called an ovum, or egg cell) is considered female, while the smaller gamete (called a spermatozoon, or sperm cell) is considered male. An individual that produces exclusively large gametes is female, and one that produces exclusively small gametes is male. An individual that produces both types of gametes is a hermaphrodite; in some cases hermaphrodites are able to self-fertilize and produce offspring on their own, without a second organism.[19]
Animals Main article: Sexual reproduction in animals
Hoverflies engaging in sexual intercourse Most sexually reproducing animals spend their lives as diploid organisms, with the haploid stage reduced to single cell gametes.[20] The gametes of animals have male and female forms—spermatozoa and egg cells. These gametes combine to form embryos which develop into a new organism.
The male gamete, a spermatozoon (produced within a testicle), is a small cell containing a single long flagellum which propels it.[21] Spermatozoa are extremely reduced cells, lacking many cellular components that would be necessary for embryonic development. They are specialized for motility, seeking out an egg cell and fusing with it in a process called fertilization.
Female gametes are egg cells (produced within ovaries), large immobile cells that contain the nutrients and cellular components necessary for a developing embryo.[22] Egg cells are often associated with other cells which support the development of the embryo, forming an egg. In mammals, the fertilized embryo instead develops within the female, receiving nutrition directly from its mother.
Animals are usually mobile and seek out a partner of the opposite sex for mating. Animals which live in the water can mate using external fertilization, where the eggs and sperm are released into and combine within the surrounding water.[23] Most animals that live outside of water, however, must transfer sperm from male to female to achieve internal fertilization.
In most birds, both excretion and reproduction is done through a single posterior opening, called the cloaca—male and female birds touch cloaca to transfer sperm, a process called "cloacal kissing".[24] In many other terrestrial animals, males use specialized sex organs to assist the transport of sperm—these male sex organs are called intromittent organs. In humans and other mammals this male organ is the penis, which enters the female reproductive tract (called the vagina) to achieve insemination—a process called sexual intercourse. The penis contains a tube through which semen (a fluid containing sperm) travels. In female mammals the vagina connects with the uterus, an organ which directly supports the development of a fertilized embryo within (a process called gestation).
Because of their motility, animal sexual behavior can involve coercive sex. Traumatic insemination, for example, is used by some insect species to inseminate females through a wound in the abdominal cavity – a process detrimental to the female's health.
Plants
Flowers are the sexual organs of flowering plants, usually containing both male and female parts. Main article: Plant reproduction Like animals, plants have developed specialized male and female gametes.[25] Within most familiar plants, male gametes are contained within hard coats, forming pollen. The female gametes of plants are contained within ovules; once fertilized by pollen these form seeds which, like eggs, contain the nutrients necessary for the development of the embryonic plant.
Pinus nigra cone.jpg Pine cones, immature male.jpg Female (left) and male (right) cones are the sex organs of pines and other conifers. Many plants have flowers and these are the sexual organs of those plants. Flowers are usually hermaphroditic, producing both male and female gametes. The female parts, in the center of a flower, are the carpels—one or more of these may be merged to form a single pistil. Within carpels are ovules which develop into seeds after fertilization. The male parts of the flower are the stamens: these long filamentous organs are arranged between the pistil and the petals and produce pollen at their tips. When a pollen grain lands upon the top of a carpel, the tissues of the plant react to transport the grain down into the carpel to merge with an ovule, eventually forming seeds.
In pines and other conifers the sex organs are conifer cones and have male and female forms. The more familiar female cones are typically more durable, containing ovules within them. Male cones are smaller and produce pollen which is transported by wind to land in female cones. As with flowers, seeds form within the female cone after pollination.
Because plants are immobile, they depend upon passive methods for transporting pollen grains to other plants. Many plants, including conifers and grasses, produce lightweight pollen which is carried by wind to neighboring plants. Other plants have heavier, sticky pollen that is specialized for transportation by insects. The plants attract these insects with nectar-containing flowers. Insects transport the pollen as they move to other flowers, which also contain female reproductive organs, resulting in pollination.
Fungi Main article: Mating in fungi
Mushrooms are produced as part of fungal sexual reproduction Most fungi reproduce sexually, having both a haploid and diploid stage in their life cycles. These fungi are typically isogamous, lacking male and female specialization: haploid fungi grow into contact with each other and then fuse their cells. In some of these cases the fusion is asymmetric, and the cell which donates only a nucleus (and not accompanying cellular material) could arguably be considered "male".[26]
Some fungi, including baker's yeast, have mating types that create a duality similar to male and female roles. Yeast with the same mating type will not fuse with each other to form diploid cells, only with yeast carrying the other mating type.[27]
Fungi produce mushrooms as part of their sexual reproduction. Within the mushroom diploid cells are formed, later dividing into haploid spores—the height of the mushroom aids the dispersal of these sexually produced offspring.
Sex determination
Main article: Sex-determination system
Sex helps the spread of advantageous traits through recombination. The diagrams compare evolution of allele frequency in a sexual population (top) and an asexual population (bottom). The vertical axis shows frequency and the horizontal axis shows time. The alleles a/A and b/B occur at random. The advantageous alleles A and B, arising independently, can be rapidly combined by sexual reproduction into the most advantageous combination AB. Asexual reproduction takes longer to achieve this combination, because it can only produce AB if A arises in an individual which already has B, or vice versa. The most basic sexual system is one in which all organisms are hermaphrodites, producing both male and female gametes—this is true of some animals (e.g. snails) and the majority of flowering plants.[28] In many cases, however, specialization of sex has evolved such that some organisms produce only male or only female gametes. The biological cause for an organism developing into one sex or the other is called sex determination.
In the majority of species with sex specialization, organisms are either male (producing only male gametes) or female (producing only female gametes). Exceptions are common—for example, in the roundworm C. elegans the two sexes are hermaphrodite and male (a system called androdioecy).
Sometimes an organism's development is intermediate between male and female, a condition called intersex. Sometimes intersex individuals are called "hermaphrodite"; but, unlike biological hermaphrodites, intersex individuals are unusual cases and are not typically fertile in both male and female aspects.
Genetic
Like humans and other mammals, the common fruit fly has an XY sex-determination system. In genetic sex-determination systems, an organism's sex is determined by the genome it inherits. Genetic sex-determination usually depends on asymmetrically inherited sex chromosomes which carry genetic features that influence development; sex may be determined either by the presence of a sex chromosome or by how many the organism has. Genetic sex-determination, because it is determined by chromosome assortment, usually results in a 1:1 ratio of male and female offspring.
Humans and other mammals have an XY sex-determination system: the Y chromosome carries factors responsible for triggering male development. The default sex, in the absence of a Y chromosome, is female. Thus, XX mammals are female and XY are male. XY sex determination is found in other organisms, including the common fruit fly and some plants.[28] In some cases, including in the fruit fly, it is the number of X chromosomes that determines sex rather than the presence of a Y chromosome (see below).
In birds, which have a ZW sex-determination system, the opposite is true: the W chromosome carries factors responsible for female development, and default development is male.[29] In this case ZZ individuals are male and ZW are female. The majority of butterflies and moths also have a ZW sex-determination system. In both XY and ZW sex determination systems, the sex chromosome carrying the critical factors is often significantly smaller, carrying little more than the genes necessary for triggering the development of a given sex.[30]
Many insects use a sex determination system based on the number of sex chromosomes. This is called X0 sex-determination—the 0 indicates the absence of the sex chromosome. All other chromosomes in these organisms are diploid, but organisms may inherit one or two X chromosomes. In field crickets, for example, insects with a single X chromosome develop as male, while those with two develop as female.[31] In the nematode C. elegans most worms are self-fertilizing XX hermaphrodites, but occasionally abnormalities in chromosome inheritance regularly give rise to individuals with only one X chromosome—these X0 individuals are fertile males (and half their offspring are male).[32]
Other insects, including honey bees and ants, use a haplodiploid sex-determination system.[33] In this case diploid individuals are generally female, and haploid individuals (which develop from unfertilized eggs) are male. This sex-determination system results in highly biased sex ratios, as the sex of offspring is determined by fertilization rather than the assortment of chromosomes during meiosis.
Nongenetic
Clownfish are initially male; the largest fish in a group becomes female For many species, sex is not determined by inherited traits, but instead by environmental factors experienced during development or later in life. Many reptiles have temperature-dependent sex determination: the temperature embryos experience during their development determines the sex of the organism. In some turtles, for example, males are produced at lower incubation temperatures than females; this difference in critical temperatures can be as little as 1–2 °C.
Many fish change sex over the course of their lifespan, a phenomenon called sequential hermaphroditism. In clownfish, smaller fish are male, and the dominant and largest fish in a group becomes female. In many wrasses the opposite is true—most fish are initially female and become male when they reach a certain size. Sequential hermaphrodites may produce both types of gametes over the course of their lifetime, but at any given point they are either female or male.
In some ferns the default sex is hermaphrodite, but ferns which grow in soil that has previously supported hermaphrodites are influenced by residual hormones to instead develop as male.[34]
Sexual dimorphism
Main article: Sexual dimorphism
Common Pheasants are sexually dimorphic in both size and appearance. Many animals and some plants have differences between the male and female sexes in size and appearance, a phenomenon called sexual dimorphism. Sex differences in humans include, generally, a larger size and more body hair in men; women have breasts, wider hips, and a higher body fat percentage. In other species, the differences may be more extreme, such as differences in coloration or bodyweight. In humans, biological sex is determined by five factors present at birth: the presence or absence of a Y chromosome, the type of gonads, the sex hormones, the internal reproductive anatomy (such as the uterus in females), and the external genitalia.[35]
Sexual dimorphisms in animals are often associated with sexual selection – the competition between individuals of one sex to mate with the opposite sex.[36] Antlers in male deer, for example, are used in combat between males to win reproductive access to female deer. In many cases the male of a species is larger than the female. Mammal species with extreme sexual size dimorphism tend to have highly polygynous mating systems—presumably due to selection for success in competition with other males—such as the elephant seals. Other examples demonstrate that it is the preference of females that drive sexual dimorphism, such as in the case of the stalk-eyed fly.[37]
Other animals, including most insects and many fish, have larger females. This may be associated with the cost of producing egg cells, which requires more nutrition than producing sperm—larger females are able to produce more eggs.[38] For example, female southern black widow spiders are typically twice as long as the males.[39] Occasionally this dimorphism is extreme, with males reduced to living as parasites dependent on the female, such as in the anglerfish. Some plant species also exhibit dimorphism in which the females are significantly larger than the males, such as in the moss Dicranum[40] and the liverwort Sphaerocarpos.[41] There is some evidence that, in these genera, the dimorphism may be tied to a sex chromosome,[41][42] or to chemical signalling from females.[43]
In birds, males often have a more colourful appearance and may have features (like the long tail of male peacocks) that would seem to put the organism at a disadvantage (e.g. bright colors would seem to make a bird more visible to predators). One proposed explanation for this is the handicap principle.[44] This hypothesis says that, by demonstrating he can survive with such handicaps, the male is advertising his genetic fitness to females—traits that will benefit daughters as well, who will not be encumbered with such handicaps.
See also
Sex and gender distinction References
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(2012) "DNA Repair as the Primary Adaptive Function of Sex in Bacteria and Eukaryotes". Chapter 1, pp. 1–50, in DNA Repair: New Research, S. Kimura and Shimizu S. (eds.) Nova Sci. Publ., Hauppauge, N.Y. ISBN 978-1-62100-756-2 https://www.novapublishers.com/catalog/product_info.php?products_id=31918 Jump up ^ Schaffer, Amanda (updated September 27, 2007) "Pas de Deux: Why Are There Only Two Sexes?", Slate. Jump up ^ Hurst, Laurence D. (1996). "Why are There Only Two Sexes?". Proceedings: Biological Sciences 263 (1369): 415–422. doi:10.1098/rspb.1996.0063. JSTOR 50723. Jump up ^ Haag ES (2007). "Why two sexes? Sex determination in multicellular organisms and protistan mating types". Seminars in Cell and Developmental Biology 18 (3): 348–9. doi:10.1016/j.semcdb.2007.05.009. PMID 17644371. Jump up ^ Stiglec R, Ezaz T, Graves JA (2007). "A new look at the evolution of avian sex chromosomes". Cytogenet. Genome Res. 117 (1–4): 103–109. doi:10.1159/000103170. PMID 17675850. 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"DMRT1 Is Upregulated in the Gonads During Female-to-Male Sex Reversal in ZW Chicken Embryos". Biology of Reproduction 68 (2): 560–570. doi:10.1095/biolreprod.102.007294. PMID 12533420. Jump up ^ "Evolution of the Y Chromosome". Annenberg Media. Retrieved 2008-04-01. Jump up ^ Yoshimura A (2005). "Karyotypes of two American field crickets: Gryllus rubens and Gryllus sp. (Orthoptera: Gryllidae)". Entomological Science 8 (3): 219–222. doi:10.1111/j.1479-8298.2005.00118.x. Jump up ^ Riddle DL, Blumenthal T, Meyer BJ, Priess JR (1997). C. Elegans II. Cold Spring Harbor Laboratory Press. ISBN 0-87969-532-3. 9.II. Sexual Dimorphism Jump up ^ Charlesworth B (2003). "Sex Determination in the Honeybee". Cell 114 (4): 397–398. doi:10.1016/S0092-8674(03)00610-X. PMID 12941267. Jump up ^ Tanurdzic M and Banks JA (2004). "Sex-Determining Mechanisms in Land Plants". The Plant Cell 16 (Suppl): S61–S71. doi:10.1105/tpc.016667. PMC 2643385. PMID 15084718. Jump up ^ Knox, David; Schacht, Caroline. Choices in Relationships: An Introduction to Marriage and the Family. 11 ed. Cengage Learning; 2011-10-10 [cited 17 June 2013]. ISBN 9781111833220. p. 64–66. Jump up ^ Darwin C (1871). The Descent of Man. Murray, London. ISBN 0-8014-2085-7. Jump up ^ Wilkinson G.S., Reillo P.R. (22 January 1994). "Female choice response to artificial selection on an exaggerated male trait in a stalk-eyed fly". Proceedings of the Royal Society B 225 (1342): 1–6. doi:10.1098/rspb.1994.0001. Jump up ^ Stuart-Smith J, Swain R, Stuart-Smith R, Wapstra E (2007). "Is fecundity the ultimate cause of female-biased size dimorphism in a dragon lizard?". Journal of Zoology 273 (3): 266–272. doi:10.1111/j.1469-7998.2007.00324.x. Jump up ^ "Southern black widow spider". Insects.tamu.edu. Retrieved 2012-08-08. Jump up ^ Shaw, A. Jonathan (2000). "Population ecology, population genetics, and microevolution". In A. Jonathan Shaw & Bernard Goffinet (eds.). Bryophyte Biology. Cambridge: Cambridge University Press. pp. 379–380. ISBN 0-521-66097-1. ^ Jump up to: a b Schuster, Rudolf M. (1984). "Comparative Anatomy and Morphology of the Hepaticae". New Manual of Bryology 2. Nichinan, Miyazaki, Japan: The Hattori botanical Laboratory. p. 891. Jump up ^ Crum, Howard A.; Anderson, Lewis E. (1980). Mosses of Eastern North America 1. New York: Columbia University Press. p. 196. ISBN 0-231-04516-6. Jump up ^ Briggs, D. A. (1965). "Experimental taxonomy of some British species of genus Dicranum". New Phytologist 64 (3): 366–386. doi:10.1111/j.1469-8137.1965.tb07546.x. Jump up ^ Zahavi, A. and Zahavi, A. (1997) The handicap principle: a missing piece of Darwin's puzzle. Oxford University Press. Oxford. ISBN 0-19-510035-2 Further reading
Arnqvist, G. & Rowe, L. (2005) Sexual conflict. Princeton University Press, Princeton. ISBN 0-691-12217-2 Alberts B, Johnson A, Lewis J, Raff M, Roberts K, and Walter P (2002). Molecular Biology of the Cell (4th ed.). New York: Garland Science. ISBN 0-8153-3218-1. Ellis, Havelock (1933). Psychology of Sex. London: W. Heinemann Medical Books. xii, 322 p. N.B.: One of many books by this pioneering authority on aspects of human sexuality. Gilbert SF (2000). Developmental Biology (6th ed.). Sinauer Associates, Inc. ISBN 0-87893-243-7. Maynard-Smith, J. The Evolution of Sex. Cambridge University Press, 1978. External links
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A

Adnate - Where the gills or tubes under the cap of a fungus are perpendicular to the stipe or stem at the point of attachment
Adnexed - Where the gills or tubes under the cap of a fungus sweep upwards before being attached to the stem
Aerial mycelium - Hyphal elements growing above the agar surface.
Agar - An extract from a seaweed used to solidify media. The agar used in mushrooms cultivation is usually available in powder form
Agaric - A term describing mushrooms and toadstools having gills beneath a cap that is connected to a stipe or stem
Alkaline - Having a pH greater than 7.
Annulus - A ring of tissue left attached to the stem of a mushroom or toadstool when the veil connecting the cap and stem ruptures as the young fruitbody develops.
Antibiotic - A class of natural and synthetic compounds that inhibit the growth of or kill other microorganisms.
Ascomycetes - A group of fungi that have in common that they produce their sexual spores inside specialized cells (asci), which usually contain eight spores.
Aseptic - Sterile condition: no unwanted organisms present
Aseptic technique - Also sterile technique. Manipulating sterile instruments or culture media in such a way as to maintain sterility.
Autoclave - Basically a big pressure cooker, sometimes operating at higher pressure than 15 PSI, thus achieving sterilization temperatures above 250?F.
Axenic - Not contaminated; gnotobiotic: Said esp. of a medium devoid of all living organisms except those of a single Species

B

Bacteria - Unicellular microorganisms that may cause contamination in culture work. Grain spawn is very easily contaminated with bacteria. On the other hand there are some bacteria that are needed for the fruiting of agaricus. These are present in the casing soil.
Basidiomycetes - A group of fungi which produce their spores externally on so called basidia. Often four spores are produced per basidium. Many basidiomycetes show clamp connections on their hyphae, ascomycetes never do. Most mushrooms are classified as basidiomycetes, whereas most molds are ascymycetic.
Basidium (pl. basidia) - A cell that gives rise to a basidiospore. Basidia are characteristic of the basidiomycetes.
Biological efficiency - The definition of biological efficiency (BE) in mushroom cultivation is: 1 pound fresh mushrooms from 1 pound dry Substrate indicates 100 % biological efficiency. This definition was first used by the agaricus industry to be able to compare different grow setups and Substrate compositions. Note that this is not the same as true thermodynamic efficiency. The BE of Psilocybe cubensis is easily somewhere in the range of 200%uFFFDbr>
Birthing - Removing the fully colonized growth medium (like a cake from its jar) from whatever container it was kept in for colonization purposes and placing in an environment conducive to fruiting.
Bolete - A group of fungi having tubes rather than gills beneath the cap
Brown Rice Flour (BRF)- Ground brown rice. Many cultivators grind their own brown rice in a coffee grinder.
Buffer - A system capable of resisting changes in pH even when acid or base is added, consisting of a conjugate acid-base pair in which the ratio of proton acceptor to proton donor is near unity. An example is gypsum, which is an additive that increases a material's pH while helping to buffer it, or keep it within a desriable (and higher) pH range.

C

CaCl2 - Calcium chloride (Brand names: Damp-Rid, Damp-Gone, Damp B Gone, Damp Away). See desiccant.
CaCO3 - See calcium carbonate.
Calcium sulfate - CaSO4. See gypsum.
Carbon dioxide - CO2. A colorless, odorless, incombustible gas. Formed during respiration, combustion, and organic decomposition.
Carpophore(s) - Commonly known as "mushrooms", the reproductive organs of the true body of the fungus, formed by the web of mycelium that colonize a substrate.
Casing - Some mushrooms need a covering layer of soil with a specific microflora for Fruiting. Casing materials include peat and vermiculite; additives include calcium carbonate, calcium hydroxide (hydrated lime) and crushed oystershells.
CaSO4 - Calcium sulfate. See gypsum.
Cellulose - Glucose polysaccharide that is the main component of plant cell walls. Most abundant polysaccharide on earth, and common source of nourishment for cultivated fungi.
Clone - A population of individuals all derived asexually from the same single parent. In mushroom cultivation placing a piece of mushroom tissue on agar medium in order to obtain growing mycelium is called cloning. This is not strictly related to the colloquial notion of cloning, and is simply a manipulation of the natural asexual reproduction system of fungi.
CO2 - See carbon dioxide
Cobweb mold - Common name for Dactylium, a mold that is commonly seen on the casing soil or parisitizing the mushroom. It is cobweb-like in appearance and first shows up in small scattered patches and then quickly runs over the entire surface of the its substrate.
Coir - Coco coir. A short coarse fiber from the outer husk of a coconut. Used as a casing ingredient. Brand names include Bed-A-Beast .
CVG aka Coir Verm Gypsum- This commonly used acronym is one of the most commonly used substrates for growing Psilocybe Cubensis. CVG can be sterilized or pasteurized unlike other substrates that would otherwise require pasteurization and can't be sterilized with the intention of spawning to bulk in open air. Coir, Coir Verm, Coir Gypsum, and Coir verm gypsum are all usable combinations.
Colonization - The period of the mushroom cultivation starting at Inoculation during which the mycelium grows through the Substrate until it is totally permeated and overgrown.
Compost - Selectively-fermented organic material. Compost is one desirable substrate for mushrooms, but may vary in its components.
Coniferous - Pertaining to conifers, which bear woody cones containing naked seeds. Relevant in mushroom hunting.
Contamination - Undesired foreign material (contaminants), frequently organisms, in a growing medium. Often the result of insufficient sterilisation or improper sterile technique.
Cottony - Having a loose and coarse texture. Referred to a growth pattern of some fungi species or strains.
Culture - A sample of a given (generally desired) organism. In mycology, mushroom mycelium growing on a culture medium.
Culture medium - The material upon which a culture is developed. Micro-organisms differ in their nutritional needs, and so large number of different growth media have been developed, PD(Y)A (potato dextrose(yeast extract) agar) and MEA (malt extract agar) can be used for most cultivated mushrooms.

D

Deciduous - Trees and plants that shed their leaves at the end of the growing season. Relevant in mushroom hunting.
Desiccant - An anhydrous (moistureless) substance, usually a powder or gel, used to absorb water from other substances. Two commonly used dessicants are calcium hydroxide and silica gel. Dessication permits mushrooms to be preserved for extended periods.
Dextrose - A simple sugar used in agar formulations. Synonymous with glucose.
Dikaryotic mycelium - Contains two nuclei and can therefore produce fruiting bodies.
Diffusion - The movement of suspended or dissolved particles from a more concentrated region to a less concentrated region as a result of random movement on the microscopic scale. Diffusion tends to distribute particles uniformly throughout the available volume, given enough time, and occurs more rapidly at higher temperatures.
Disinfection - To cleanse so as to destroy or prevent the growth of microorganisms, usually referring to rubbing or spraying the surfaces one wants to disinfect with lysol, diluted bleach solutions or alcohol.

E

Endospore - A metabolically dormant state by which some bacteria become more resistant to heat, chemicals, and other adverse conditions. Given the proper conditions, they will reactivate (germinate) and begin to multiply. Many bacterial endospores cannot be destroyed at boiling temperatures. This is important to mycologists because grains contain a high number of dormant endospores, though rice often contains few to none; thus, many grains must be pressure cooked to achieve sterilization, whereas brown rice flour may simply be boiled.
Enzyme - A protein, synthesized by a cell, that acts as a catalyst for a specific chemical reaction.

F

Fermentation - Anaerobic (oxygen-less) decomposition. In mushroom cultivation, this often relates to composting. Easily-accessible nutrients may be degraded by micro-organism, making a substrate more selectively beneficial to the desired fungus. Unwanted fermentation may occur if the composted substrate is still very 'active' after inoculation or if thick layers or large bags are used. The latter may lead to low-oxygen conditions in parts of the substrate. Mushrooms are aerobic, meaning they need oxygen, while some undesirable bacteria thrive in anaerobic conditions.
Field capacity - Content of water, on a mass or volume basis, remaining in a soil after being saturated with water and after free drainage is negligible. Described as the state achieved when one can squeeze a handful of substrate or casing material hard, only to have one or two drops emerge.
Flow hood - A fan-powered and HEPA-filtered device that produces a laminar flow of contam free air. The air moves across the workspace allowing for open sterile work without the hassle and inconvience of a glove box.
Flush - The sudden development of many fruiting bodies at the same time. Usually there is a resting period between flushes.
Fractional sterilization - A sterilization method used to destroy bacteria and spores in preparation of grain spawn (rye, wheat, birdseed) requiring no pressure cooker. In this case, the jars fitted with a filter are boiled or steamed at 212?F (100?C) for 30 min in a covered pot, three days in a row. Between the boiling steps the jars are best kept warm, around 30?C, to allow the remaining endospores to germinate. The basic principle behind this method is that any resistant bacterial spores should germinate after the first heating and therefore be susceptible to killing during the subsequent boilings.
Fruiting - The process by which the mycelium produces fruiting bodies, or mushrooms, for the purpose of spore propagation (sexual reproduction).
Fruiting body - A mushroom. The part of the mushroom that grows above ground.
Fruiting chamber (FC) - A enclosed space with high humidity and fresh air exchange where mushrooms may fruit under proper conditions.
Fungicide - A class of pesticides used to kill fungi.
Fungus - A group of organisms that includes mushrooms and molds. These organisms decompose organic material, returning nutrients to the soil.

G

G2G - See grain-to-grain transfer. Inoculation of grain by already colonized grain.
Genotype - The set of genes possessed by an individual organism.
Geolite - One of several brand names/varieties of clay aggregate medium (also known as LECA for light expanded clay aggregate). It is a lightweight, porous substrate with excellent aeration.
Germination - The spreading of hyphae from a spore
Gills - The tiny segments on the underside of the cap. This is where the spores come from.
Glovebox - A glovebox is a device used to Isolate an area for work with potentially hazardous substances or materials which need to be free from direct contact with the outside environment for any reason. Most gloveboxes are small, tightly enclosed boxes having a glass panel for viewing inside and special airtight gloves which a person on the outside can use to manipulate objects inside.
Glucose - See dextrose.
Grain-to-grain transfer - The inoculation of grain with already-colonized grain. This procedure involves exposing uncolonized, sterilized grain, and so is prone to contamination. As such it should only be performed with a glove box, laminar flow hood, or similar device.
Gypsum - Calcium sulfate, CaSO4. A greyish powder often used in spawn preparation. It prevents the clumping of the grain kernels and acts as a basic pH buffer.

H

H2O2 - See hydrogen peroxide.
Hay - Grass that has been cut, left to dry in the field and then baled. It is fed to livestock through the winter when fresh grass is not available. The color of hay is greenish-grey. Not synonymous with straw.
HEPA - High Efficiency Particulate Air filter. A high-efficiency filter used in flow hoods.
Hydrogen peroxide - A clear aqueous solution usualy available in concentrations from 3%uFFFDo 30%uFFFDEasily decomposed into water and oxygen by enzymes like catalase, which is found in desirable mushrooms but not in many bacteria. This makes it capable of selectively destroying some competitors, and a tool sometimes used in cultivation. The mycological use of peroxide was the focus of a popular cultivation guide by Rush Wayne.
Hypha(e) - Filamentous structure which exhibits apical growth and which is the developmental unit of a Mycelium.

I

In vitro - From the Latin, in glass, isolated from the living organism and artificially maintained, as in a petri dish or a jar.
Incubation - The period after inoculation (preferably at a temperature optimal for mycelial growth) during which the Mycelium grows vegetatively
Inoculation - Introduction of spores or spawn into substrate
Isolate - A strain of a fungus brought into pure culture (i.e. isolated) from a specific environment

J

K

L

Lamellae - The gills of a mushroom
LC - See liquid culture
Lignin - A complex polymer that occurs in woody material of higher plants. It is highly resistant to chemical and enzymatic degradation. The white rot fungi are known for their lignin degrading capability.
Limestone - See calcium carbonate.
Liquid culture - A culture of mycelium suspended in a nutritious liquid, for use as an inoculant.

M

Magic mushroom - Any of a number of species of fungi containing the alkaloids psilocybin and/or psilocin. Common species are the 'liberty cap' (Psilocybe semilanceata) and Psilocybe cubensis, though there are dozens of others.
Maltose - Malt sugar, used in agar formulations.
Martha - Refers to a fruiting chamber based on a Martha Stewart-brand translucent vinyl closet.
MEA - Malt extract agar.
Metabolism - The biochemical processes that sustain a living cell or organism.
Multispore - Refers to an inoculation where multiple germinations and matings occur due to the use of various spores, as in a spore solution (e.g. spore syringe) and as opposed to an isolate. Liquid cultures may sometimes be called multispore (though they contain no spores) if they were produced from a spore solution, rather than an isolate.
Mycelium - The portion of the mushroom that grows underground. Plants have roots; mushrooms have mycelium. Mycelium networks can be huge. The largest living thing in the world is a single underground mycelium complex.
*Mycorrhiza# - A symbiotic association between a plant root and fungal hyphae.

N

O

Overlay - A dense mycelial growth that covers the casing surface and shows little or no inclination to form pinheads. Overlay directly results from a dry casing, high levels of carbon Dioxide and/or low humidity.
Oyster shells - See calcium sulfate.

P

Parasitic - Fungi that grow by taking nourishment from other living organisms.
Pasteurization - Heat treatment applied to a Substrate to destroy unwanted organisms but keeping a reduced concentration of favorable ones alive. The temperature range is 60?C to 80?C(140?F-175?F). The treatment is very different from sterilization, which aims at destroying all organisms in the substrate .
PDA - Potato dextrose agar.
PDYA - Potato dextrose yeast agar.
Peat - Unconsolidated soil material consisting largely of undecomposed, or only slightly decomposed, organic matter accumulated under conditions of excessive moisture. Used as casing ingredient in mushroom culture.
Perlite - Perlite is a very light mineral, often found next to the vermiculite in gardening stores. It has millions of microscopic pores, which when it gets damp, allow it to 'breathe' lots of water into the air, aiding in humidification, which is beneficial to fruiting. Peroxidated agar - Agar made with H2O2 for the purpose of retarding contamination by bacteria and new mold spores. Not suitable for use with ungerminated mushroom spores, only live mycelium. See also: hydrogen peroxide.
Petri dish - A round glass or plastic dish with a cover to observe the growth of microscopic organisms. The dishes are partly filled with sterile growth medium such as agar (or sterilized after they have been filled). Petri dishes are used to produce isolates.
PF - Psylocybe Fanaticus. The original spore provider and originator of the PF-Tek, one of the original home growing techniques on which many others are based.
pH - A measure to describe the acidity of a medium. pH 7 is neutral; higher means Alkaline, lower Acidic
Pileus - The cap of a mushroom.
Pinhead - A term to describe a very young mushroom, so-named for the pin-sized developing cap.
Polyfill - A polyester fiber that resembles synthetic cotton. Found at fabric stores, Wal-Mart, arts & craft stores. Also used as a filter medium for aquariums (filter floss). Used as a jar lid filter in preparation of grain spawn and for other filtration purposes.
Pressure cooker - A pot with a tight lid in which things can be cooked quickly with steam under higher pressure. The reason for it is that at 15 PSI (pound per square inch) pressure the water boils at a higher temperature (250?F, 121?C) than at ambient pressure.(212?F, 100?C). In mushroom cultivation used to thoroughly sterilize substrates and agar media.
Primordium - The initial fruiting body, the stage before pinhead
Psilocybin, Psilocin - Hallucinogenic organic compounds found in some mushrooms.
Pure culture - An isolated culture of a micro-organism, uncontaminated with others. Pure cultures are essential to the production of spawn because it is sensitive to contamination.

R

Rhizomorph - "Root-like". An adjective used to describe the appearance of the mycelium of some mushroom strains. Rhizomorphic mycelium is taken as a sign of fast colonization and qualities desirable for fruiting.
Rice cake - Many of the growing methods involve making a 'cake' of brown rice flour( BRF ), vermiculite and water, and injecting it with mushroom spores. Not a rice cake like you'd buy in a supermarket!
Rye - A hardy annual cereal grass related to wheat. Lat.:Secale cereale. In mushroom cultivation rye grain is used as spawn medium.
Ryegrass - A perennial grass widely cultivated for pasture and hay and as a lawn grass. Lat.:Lolium perenne. Seeds used as Substrate for P. mexicana and P. tampanensis.

S

Saprophyte - A fungus that grows by taking nourishment from dead organisms
Sclerotium - A hard surfaced resting body of fungal cells resistant to unfavorable conditions,which may remain dormant for long periods of time and resume growth on the return of favorable conditions.
Secondary metabolite - Product of intermediary metabolism released from a cell, such as an antibiotic.
Selective medium - Medium that allows the growth of certain types of microorganisms in preference to others. For example, an antibiotic-containing medium allows the growth of only those microorganisms resistant to the antibiotic.
Simmer - To cook just below or at the boiling point.
Slant - A test tube with growth medium, which has been sterilized and slanted to increase the surface area
Spawn - Culture of mycelium on grain, sawdust, etc., used to inoculate the final substrate, or bulk.
Spawn run - The vegetative growth period of the mycelium after spawning the substrate to bulk.
Species - Fundamental unit of biological taxonomy. Generally spoken, two individuals belong to the same species if they can produce fertile offspring
Spore print - A collection of spores taken from a mushroom cap, often collected on sterile card stock, aluminum foil, or some other flat surface.
Spore syringe - A solution of spores collected in a syringe, usually scraped from a spore print under sterile conditions. Several companies will sell you ready-to-use spore syringes for a few pounds/dollars. This site has links to, or address for, many of the most reputable of these companies.
Spores - Means of sexual reproduction for mushrooms and many other fungi. Comparable to a plant seed, save that spores combined sexually with one another after germination; there are no "male" and "female" spores as with seeds and pollen or sperm and eggs, but compatability is complicated. Spores are microscopic, and any visible clump of spores is in fact a collection of many thousands or millions of spores.
Stamets, Paul - The owner of Fungi Perfecti and mushroom guru. The co-author of The Mushroom Cultivator and many other helpful books.
Stem - The stipe or stalk of a growing mushroom.
Sterilization - Completely destroying all micro organisms present, by heat (autoclave, pressure cooker) or chemicals. Spawn substrate always has to be sterilized prior to inoculation.
Stipe - The stem of a mushroom at the top of which the cap or Pileus is attached
Strain - A genetic line considered to have common traits, usually identified for artificial selection by humans. Many strains have geographical names (e.g. Ecuador, Texan, Aussie), but point of natural origin is not necessarily the source of the name. Remember that strains are a human notion; vendors often differentiate between stocks that are not visibly different to everyone, but which have been perceived to have different characteristics, whether visual (e.g. the Penis Envy strain), chemical (as in strains perceived to have high potency), or behavioral (relating to the mushroom's response to environment, colonization speed, et cetera).
Straw - The dried remains of fine-stemmed cereals (wheat, Rye, barley...) from which the seed has been removed in threshing. Straw has a golden color.
Stroma - Dense mycelial growth without fruiting. Stroma occurs if spawn is mishandled or exposed to harmful petroleum-based fumes or chemicals. It also occurs in dry environments.
Substrate - Whatever you're using to grow the mushrooms on. Different varieties of mushroom like to eat different things (rice, rye grain, straw, compost, woodchips, birdseed). Different techniques involve infecting substrates with anything from spores, to chopped-up Mycelium, to blended mushroom.

T

Tek - Short for technique. Often prefaced with something to tell you what type of tek; e.g. PF-Tek, for Psylocybe Fanaticus Technique, one of the original home growing techniques on which many others are based.
Terrarium - A small enclosure or closed container in which selected living plants, fungi and sometimes small land animals, such as turtles and lizards, are kept and observed.
Tissue culture - Tissue cultures are the simplest way to obtain a mycelial culture. A tissue culture is essentially a clone of a mushroom, defined as a genetic duplicate of an organism. The basic procedure is to sterilely remove a piece of the mushroom cap or stem, and place it on an agar plate. After a week to ten days, Mycelium grows from the tissue and colonizes the agar. Great care should be taken to select a fruiting body of the highest quality, size, color, shape or any highly desired characteristic.
TiT - "Tub in Tub", refers to an incubator consisting of 2 plastic tubs and an aquarium heater.
Trichoderma - A common green mold.
Trip - What happens when you eat the finished product, if you are cultivating hallucinogenic varieties. With psilocybes, a trip tends to last from three to six hours. May range from mild visual effects and lightly enhanced perceptions, to a totally altered state of consciousness. Generally, this can be controlled to some degree by mindset, setting and dosage. Read some of the trip reports to get an idea of what other people have experienced before experiencing hallucinogens. Please always remember, although many of the effects seem to be experienced by many different people, you're going to have your trip, not someone else's.
Tyndallization - See fractional sterilization

U

Umbonate - Used to describe a cap with a raised central area above the point where the stipe meets the pileus

V

Veil - When a mushroom is growing, the edges of the cap are joined to the stem. As the mushroom grows larger, the cap spreads and the edges tear away, often leaving a very thin veil of material hanging from the stem.
Vermiculite - A highly absorbent material made from puffed mica. Used in rice cakes to hold water, and to stop the cake being too sticky. The mycelium likes room to breathe and grow.

W

WBS - Wild bird seed. Millet-based birdseed; used as spawn and Substrate in mushroom cultivation.

Z

Zonate - Marked with concentric bands of colour. Refers to the appearance of mycelium of some mushroom species on agar, for instance P. mexicana.