Tag Archives: evolution

2022 findings on human evolution and anthropology

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Highlights of things that caught my eye from this Smithsonian article:

  • “there is no strong relationship between eating more meat and the evolution of larger brains in our ancestors.” [sorry, Liver King] But learning to cook meat was probably important. We knew how to make and control fire for hundreds of thousands of years before we started using it for cooking, probably starting with fish.
  • Beer is about as old as agriculture, with the oldest known examples originating in Egypt. “Dating to 5,800 years ago, hundreds of years before Egypt’s first pharaoh, this beer was thick like a porridge rather than watery and probably used for both daily consumption and ritual purposes.” [Sounds like alcoholic oatmeal, and maybe not so delicious, but it fits with the idea of beer as a basic food.]
  • Dogs came from wolves, which we know, but the precise group of wolves serving as the genetic ancestor of modern dogs has not been found [aliens?].
  • The earliest known chicken domestication occurred in modern-day Thailand, and again is about as old as agriculture.
  • One of the oldest “possible hominims” (6-7 million years) was identified in modern day Chad. They could walk, but based on their bodies still spent a lot of time in trees. [Stop the planet of the apes, I want to get off!]
  • Modern humans and Neanderthals were both around in modern-day Europe as long as 50,000 years ago, meaning they co-existed and interbred for longer than previously thought. The Nobel Prize went to a scientist who sequenced the Neanderthal genome in 2010.
  • Chimpanzees and gorillas sometimes hang out and let their children play together in the wild.
  • Evidence of successful limb amputations (meaning the patients lived) predates agriculture. This might seem gross, but is evidence of “advanced medical knowledge”.
  • Humans have more genetic defenses against dementia than other animals, and this may have resulted somewhat by accident thanks to genes that evolved to cope with gonorrhea.

Troy McClure was Phil Hartman. Rest in peace, Phil Hartman.

astrobiologists on what aliens might actually look like

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Well, astrobiologists don’t know what aliens might look like, because they haven’t observed any. But they do have an idea what conditions on other planets (“at least 100 billion in our galaxy alone”) might be like, and by assuming the principles of evolution and natural selection will apply, they can theorize what kinds of organisms might inhabit them.

Darwin’s aliens
Making predictions about aliens is not an easy task. Most previous work has focused on extrapolating from empirical observations and mechanistic understanding of physics, chemistry and biology. Another approach is to utilize theory to make predictions that are not tied to details of Earth. Here we show how evolutionary theory can be used to make predictions about aliens. We argue that aliens will undergo natural selection – something that should not be taken for granted but that rests on firm theoretical grounds. Given aliens undergo natural selection we can say something about their evolution. In particular, we can say something about how complexity will arise in space. Complexity has increased on the Earth as a result of a handful of events, known as the major transitions in individuality. Major transitions occur when groups of individuals come together to form a new higher level of the individual, such as when single-celled organisms evolved into multicellular organisms. Both theory and empirical data suggest that extreme conditions are required for major transitions to occur. We suggest that major transitions are likely to be the route to complexity on other planets, and that we should expect them to have been favoured by similarly restrictive conditions. Thus, we can make specific predictions about the biological makeup of complex aliens.

Cambridge University Press

Shouldn’t the abstract give us some idea of what those “specific predictions” are? Luckily, this is an open access article. There are some fun passages about why my hands are willing to help my testicals reproduce, rather than trying to reproduce themselves. This is because “their interests are aligned”, and my testicles have (or once had, at the risk of providing way too much information to the reader…) the potential to produce more hands at some point. Like a termite colony, I have gone through a transition to a complex organism, and my various parts are not out for themselves but are working together in a harmonious whole. (That’s the theory, although I’m not sure those testicles were aligned with my brain during my teenage years…)

So there might be simple alien life out there, in the form of single-celled viruses, fungi, bacteria, algae, or whatever. What we are really interested in is complex alien life, which would consist of “a nested hierarchy of entities, with the conditions required to eliminate conflict at each of those levels”. They could have complex individual bodies along the lines of ours, or some kind of creepy colonies made up of simpler organisms, more like ants or termites but with more tentacles. There are some pictures in the paper, have a look.

Universities have astrobiology departments, and it seems like a fun thing to study. You get to learn about biology and astronomy, combine theory and observation.

dogs domesticated themselves

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I had heard that dogs may have been domesticated as a food animal at some point, which is a somewhat dark tale for the modern dog lover. This Independent article says new evidence tells a different story. First, Siberian wolves started sniffing around garbage in human settlements during the ice age. Then, they settled in. Although it might seem like humans would feel threatened by wolves in their midst, they may actually have helped defend the human settlements against other animals, including other wolves. (You can imagine there might have been a few misunderstandings early on where hungry wolves ate people and vice versa.) And then, because they are so smart, a specific pack of wolves would pass behaviors down from generation to generation, and in just a few generations you would have a population with distinct behavior and over time even a distinct appearance. At some point, humans did start training and breeding them to perform specific tasks, like pulling sleds.

teeth: miracle or weakness of evolution?

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I’ve always thought that teeth might be the weakest point of the human body. Why did our teeth evolve to be made of calcium, which dissolves in acid, when pretty much all our food is acidic? Why do we have to strap metal torture devices to children’s teeth for years just for them to be reasonably straight? Why don’t animals seem to have these problems?

This article in Scientific American sings the praises of teeth. It argues that, like many of our other organs and systems, our modern lives just aren’t what they evolved to deal with. It basically comes down to the idea that our food is too sweet and too soft.

The evolutionary history of our teeth explains not only why they are so strong but also why they fall short today. The basic idea is that structures evolve to operate within a specific range of environmental conditions, which in the case of our teeth include the chemicals and bacteria in the mouth, as well as strain and abrasion. It follows that changes to the oral environment can catch our teeth off guard. Such is the case with our modern diets, which are unlike any in the history of life on our planet. The resulting mismatch between our biology and our behavior explains the dental caries (cavities), impacted wisdom teeth and other orthodontic problems that afflict us.

Scientific American

I admit, I don’t like working for my food – I like boneless, seedless, shell-less everything. My teeth may have paid the price.

Red Queens and Black Queens

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It sounds like a fantasy novel, but the Red Queen hypothesis is about species competing and co-evolving with one another over long periods of time. It is named after the Red Queen in Through the Looking Glass, who said “it takes all the running you can do, to keep in the same place.” In other words, species have to constantly evolve and adapt, or they go extinct. 

The Black Queen hypothesis is hard for me to understand, but it refers to

the queen of spades in the game Hearts, where the usual strategy is to avoid taking this card. Gene loss can provide a selective advantage by conserving an organism’s limiting resources, provided the gene’s function is dispensable. Many vital genetic functions are leaky, thereby unavoidably producing public goods that are available to the entire community. Such leaky functions are thus dispensable for individuals, provided they are not lost entirely from the community. The BQH predicts that the loss of a costly, leaky function is selectively favored at the individual level and will proceed until the production of public goods is just sufficient to support the equilibrium community; at that point, the benefit of any further loss would be offset by the cost. Evolution in accordance with the BQH thus generates “beneficiaries” of reduced genomic content that are dependent on leaky “helpers,” and it may explain the observed nonuniversality of prototrophy, stress resistance, and other cellular functions in the microbial world.

In other words, organisms can sort of help their rivals, and there can be some survival advantage to this over long periods of evolutionary time. I’m not sure I quite get it, but there it is.

the “Scopes Monkey Trial of the 21st Century”

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From Bloomberg BNA,

A federal judge said he wanted to avoid having “the Scopes Monkey Trial of the 21st Century,” and ordered an environmental organization to remove claims based on climate change in its lawsuit against Exxon Mobil Corp.

Judge Mark Wolf said he did not want the lawsuit to turn into a trial about whether climate change exists, the way the 1925 trial about whether evolution could be taught in Tennessee public schools took up the debate about human origin…

Wolf said he would not dismiss the suit. But he told the environmental organization to amend its 14-count complaint and strip out major references to harm caused by climate change that would take place in 2050 and later.

I hadn’t thought of it before but I think the comparison is perfect! Almost 100 hundred years on from the Scopes trial, a large majority of rational, educated people correctly see that debate as a silly footnote to an ignorant, bygone era. Climate change is similar, except we were never seriously worried about the apes rising up and swamping us (you maniacs!)

But on a more serious note, why is a judge qualified to identify the best planning horizon when considering risk of failure of an industrial facility? That should depend on the expected life of the facility, external threats that might occur (like climate change), likelihood and consequence of failure during that period. If an oil and gas tank farm would tend to be retired or rebuilt every 30 years or so (and I suspect it might), it would make sense to take into account only the risks expected to take place over that time period, so 2050 might actually be a reasonable decision.

the chicken and the egg

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This video purports to answer the question of the chicken and the egg once and for all. But really, it’s silly. Of course there were eggs of some sort long before chickens existed. The real question is what came first, the chicken or the chicken egg. And even that might seem obvious – at some point something that was not quite a chicken laid an egg, and the thing that came out was a chicken. But was that egg a chicken egg? You could say that if a chicken came out, it was a chicken egg. But imagine this – if you took an egg laid by a duck, I think we could all agree that would be a duck egg. But now imagine you use some genetic technology to change the duck embryo inside the egg from a duck to a chicken. Now is it a chicken egg or a duck egg. See, it is still ambiguous.

Time Chicken from Nick Black on Vimeo.

disgust and morality

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This article claims that our natural disgust at parasites and other gross things is the origin of morality.

A ballooning body of research by Pizarro and others shows that moral judgments are not always the product of careful deliberation. Sometimes we feel an action is wrong even if we can’t point to an injured party. We make snap decisions and then – in the words of Jonathan Haidt, a social psychologist at New York University – ‘construct post-hoc justifications for those feelings’. This intuition, converging lines of research reveal, is informed by disgust, an emotion that most scientists believe evolved to keep us safe from parasites. Marked by cries of ‘Yuck!’ and ‘Ew!’, disgust makes us recoil in horror from faeces, bed bugs, leeches and anything else that might sicken us. Yet sometime deep in our past the same feeling that makes us cringe at touching a dead animal or gag at a rancid odour became embroiled in our most deeply held convictions – from ethics and religious values to political views…

These and related studies raise an obvious question: how have parasites managed to insinuate themselves into our moral code? The wiring scheme of the brain, some scientists believe, holds the key to this mystery. Visceral disgust – that part of you that wants to scream ‘Yuck!’ when you see an overflowing toilet or think about eating cockroaches – typically engages the anterior insula, an ancient part of the brain that governs the vomiting response. Yet the very same part of the brain also fires up in revulsion when subjects are outraged by the cruel or unjust treatment of others. That’s not to say that visceral and moral disgust perfectly overlap in the brain, but they use enough of the same circuitry that the feelings they evoke may sometimes bleed together, warping judgment…

From this point in human social development, it took a bit more rejiggering of the same circuitry to bring our species to a momentous place: we became disgusted by people who behaved immorally. This development, Curtis argues, is central to understanding how we became an extraordinarily social and cooperative species, capable of putting our minds together to solve problems, create new inventions, exploit natural resources with unprecedented efficiency and, ultimately, lay the foundations for civilisation.

This has interesting implications for the idea that there might be a “common morality”, akin to “common sense”, that just naturally applies to all rational people, although rational people might disagree about exactly what is included, just as scientists argue about the nature of reality but agree there is a single reality that can eventually be discovered. This is powerful because we can’t rely on reason alone as a guide to morality – there are sometimes things we could do that would be rational, but almost everyone would agree are wrong. Obvious examples would be if you could benefit yourself by lying, cheating, stealing, or killing, and be sure you could get away with it. In this case your gut tells you this is wrong even though it might be strictly rational, and that will be enough to deter most people. But if that gut sense of common morality is based partly on biological impulses shaped by past conditions that no longer apply, then maybe we should rely more on reason and less on our gut impulses of what is right and wrong.

Unnatural Selection

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Amazon description:

Gonorrhea. Bed bugs. Weeds. Salamanders. People. All are evolving, some surprisingly rapidly, in response to our chemical age. In Unnatural Selection, Emily Monosson shows how our drugs, pesticides, and pollution are exerting intense selection pressure on all manner of species. And we humans might not like the result.

Monosson reveals that the very code of life is more fluid than once imagined. When our powerful chemicals put the pressure on to evolve or die, beneficial traits can sweep rapidly through a population. Species with explosive population growth—the bugs, bacteria, and weeds—tend to thrive, while bigger, slower-to-reproduce creatures, like ourselves, are more likely to succumb.

Monosson explores contemporary evolution in all its guises. She examines the species that we are actively trying to beat back, from agricultural pests to life-threatening bacteria, and those that are collateral damage—creatures struggling to adapt to a polluted world. Monosson also presents cutting-edge science on gene expression, showing how environmental stressors are leaving their mark on plants, animals, and possibly humans for generations to come.