Your Jaw Is Basically a Fish Gill (Plus Millions of Years of Evolution)

As you sit at your desk and chew your morning muffin, consider the complicated interlocking structure of your jaw. How did you manage to evolve such a thing? What you’re eating through is essentially a badly deformed but useful gill, and we’ll tell you how it got to be that way.

Source: Your Jaw Is Basically a Fish Gill (Plus Millions of Years of Evolution)

Too bad we can’t still breathe through water – stupid choking hazard :/

Ancient Humans Had More DNA Than We Have Now

A new atlas of human genetic diversity reveals what human ancestors’ DNA may have looked like before people migrated out of Africa.

Ancestral humans carried 40.7 million more DNA base pairs than people do today, researchers report online August 6 in Science. That’s enough DNA to build a small chromosome, says study coauthor Evan Eichler, an evolutionary geneticist at the University of Washington in Seattle.

Source: Ancestral humans had more DNA

The news isn’t that surprising – we’ve know that the Y chromosome is shrinking.  The media initially portrayed this as doom saying, that men were going to disappear…

How does DNA get shorter?  DNA in chromosomes can move around, which leads to a bunch of different methods that leads to deletion.

One such example is during crossing over, of which you may be aware. But as a crude refresher/description: homologous chromosomes line up during meiosis (mitosis as well, but meiosis occurs in sex cells, which is how we inherit DNA). Your paternal chromosome and maternal chromosome pair up, and since they’re homologous (but not identical), the tips of each chromosomes can cross over/switch. Now you have two new homologous chromosomes.

However, sometimes, when they line up, they don’t line up perfectly, and a larger portion will cross over with a shorter portion. Then, the new chromosomes will be of different size: one will have an addition, and the other will have a deletion.

These additions/deletions can cause mutations/disease, but they can be silent too.  Also, the ends of chromosomes (telomeres) aren’t replicated during cell division.  So after many cycles, chromosomes get shorter and shorter.

The Pig Tooth That Spurred A Century Of Debate About Evolution

In 1922, papers around the world trumpeted the discovery of the oldest human fossil ever yet discovered — “Nebraska Man.” If you haven’t heard about it, it’s because you don’t hang out on creationist websites.

Source: The Pig Tooth That Spurred A Century Of Debate About Evolution

The endurance of Nebraska Man in Creationist mythology is at once unsettling and encouraging. Unsettling somebody misidentified pig teeth one time (don’t mention the correction), so all paleontologists must be wrong about everything. Encouraging because things like this are literally all they have.

Are Limited Lifespans An Evolutionary Adaptation?

Since the time of Darwin, evolutionary biologists have wondered why the lifespans of different species vary so significantly. A new model now suggests that the life expectancy of any given species is a function of evolutionary pressures — a conclusion that hints at the potential for powerful anti-aging interventions in humans.

Source: Are Limited Lifespans An Evolutionary Adaptation?

I always take issue with lengthening the human lifespan.  The inevitable competition for resources, considering that population growth is [currently] logarithmic.  Resources includes jobs – locally, we have seniors competing with teens for jobs because the seniors don’t have enough accumulated via  investments or a pension.  Then there’s the question: will long life be a matter of quantity vs quality?  At some point I will have to surrender my drivers license (assuming cars aren’t self-driving), but being unable to look after myself is not what I consider “living”.

The article does not mention:

  • telomeres, which are generally regarded as an indication of mortality
  • species lifespan in the wild vs captivity

Our Taste for Alcohol Goes Back Millions of Years

Alcohol has been part of human existence for millennia. Alcoholic beverages are an integral part of human culture. Like the wines consumed in Jewish and Christian rituals, these drinks have ceremonial and religious uses. Until the nineteenth century, beer, brandy, rum or grog was the drink of choice for sailors in lieu of stagnant water during long voyages. Alcohol is a social lubricant, an anesthetic and an antiseptic. It is one of the most widely used drugs in the world and has been manufactured since the advent of agriculture nearly 9000 years ago.  How is it that this drug — an intoxicating poison — has become such a part of human existence?

Source: Our Taste for Alcohol Goes Back Millions of Years

The majority of the article talks about the enzyme details…

While we started making alcohol when we figured out agriculture some 9,000 years ago, the research suggests that we’ve had exposure as far back as 10 million years ago.  Now consider that the Y-chromosomal Adam is believed to be ~208,300 years old (vs 200,000 years for Mitochondrial Eve).  Some posit that alcohol is what prompted agriculture – what a sobering thought.  Agriculture almost destroyed civilization

Alcohol is Paleo!

Alcohol is Paleo!

Asian Cuisine: Where’s the Cheese?

Lactose is the sugar in milk. Your body can’t use lactose directly, so lactose gets broken down into simpler sugars with the enzyme lactase. Mammals naturally produce lactase during infancy to nurse from their mothers, but then stop producing it as they grow older because originally they would not consume milk ever again.  Which is part of the supporting evidence for those against drinking milk/consuming dairy – we’re the only mammal to continue to drink milk after infancy.  But we’re also the one of the few things that uses tools, or are capable of speech.  All courtesy of evolution… 😉

As we evolved, we also got into agriculture and domesticating milk-producing animals such as goats or cows – gaining the ability to consume milk as adults. Our original state did not allow us to do that, but some individuals possessed a mutation wherein they would continue producing lactase as adults and thus allowing them to consume milk. In some cultures that trait was very valuable, resulting in increased survival and reproduction, so the trait became very common and eventually the norm. In other cultures the trait had no net gain and therefore does not propagate, and so not take hold.  What makes adult lactase production worthless for East Asians? It has to do with geography and available sources of calcium and vitamin D.

You need calcium in your diet. You can get that calcium from dairy products (milk, yogurt, cheese), or tofu, sardines and leafy green vegetables. To make use of calcium your body also needs either vitamin D or lactose. You can get vitamin D from salmon, sardines, milk, tuna, eggs, or Shiitake mushrooms …or your body can make it when exposed to sunlight. Without vitamin D, lactose assists with the use of calcium. So, cultures with easy access to leafy greens plus sunlight or fish, calcium is taken care of and milk has no advantage. Cultures without access to leafy greens, sunlight or seafood need dairy either as a source of calcium, lactose, or both.

There is a difference between dairy that’s fermented (yogurt or most cheese) or unfermented (straight up milk). Fermented dairy products still have the calcium, but the lactose is broken down into simpler sugars, so lactase is not necessary to digest it. I suggest a study with a sample of at least 10 lactose intolerant people to test various fermented dairy products… and only one bathroom.   You could call the paper “Insane in the Methane”…  A culture with access to fish or sunlight but not leafy greens would benefit greatly from keeping dairy animals, but don’t benefit from still creating lactase as adults. They consume the milk as yogurt or cheese to get all the calcium they need and make use of that calcium, thanks to vitamin D.

While most attribute lactose tolerance to Northern Europeans, they were not the first people to have cheese – nor were they the originators of western civilization. Agriculture and domestication began in the Near East (Ancient Iraq, Syria etc) and they utilized their sheep (the first domesticated herd animal) for milk and cheese,  while creating massive cities and infrastructure while the Europeans were sitting in tents or mud huts hunting deer. Sure, groups like the Scythians who were a nuisance to the Assyrians existed, but they never had infrastructure and true “civilization”. Civilization (and cheese) originated in the Ancient Near East. The Greeks then borrowed civilization from the Ancient Near East, and later the Romans borrowed civilization from the Greeks – spreading civilization to Northern Europe.  [insert Life of Brian reference here]

Only the Asians living current day China, specifically far inland and to the north, would have an issue with lactose.  Those peoples who became the Mongols, who did consume dairy. Furthermore even fermented dairy never took hold in Chinese culture because of their trade networks – the Chinese were able to obtain their labor animals from other cultures (Tibetans, Mongols, etc).  They did not breed their own cows or goats – pigs were the primary meat animal raised. With no need for dairy, and without really having it around in the first place, they developed into a culture with virtually zero dairy of any type. Chinese culture influenced many others in Asia.

TLDR: It’s not that surprising when you realize that roughly 25% of the world’s population is lactose tolerant.  Most Asian populations are lactose intolerant.

GMO-Free Crop “refuges” Limit Bugs’ Ability to Develop Resistance

One of the most successful forms of genetically modified crops are the species that have been engineered to express bacterial proteins that are lethal to insects that ingest them. These crops have picked up the name “Bt,” for Bacillus thuringiensis, the bacteria that originally made the toxins. There are Bt versions of food crops such as corn and soy beans, as well as the commercial crop cotton.

The danger with these crops is that they’ll do what every other insecticide has done throughout history: select for the evolution of resistance. In the US, government regulations require that Bt crops be planted along with some fields sown with their non-Bt versions, called refuges. This ensures that any rare resistant individuals will likely mate with non-resistant animals that fed on the insecticide free crops, diluting out the resistance genes.

Source: GMO-free crop “refuges” limit bugs’ ability to develop resistance

Interesting read on the arms race between insect resistant crops and insects who evolve to tolerate what was engineered to be toxic to them.  And because of the short lifespan of insects, we can see the evolution unfold before us.

The Arbitrary Science of GMO Food Labeling

So far this year, 25 state legislatures have proposed mandatory labeling of genetically modified foods. But a look at existing measures around the country reveals widespread discrepancies over which foods should be included or declared exempt—raising concerns that we’re heading toward a regulatory train wreck.

…Should milk derived from a dairy cow that ate genetically modified feed be labeled a GMO food?

Source: The Dubious Science Of GMO Food Labels

Everything we eat has been shaped by modification of its genetic makeup through slow, haphazard means of selective breeding and hybridization.