Why do humans have so little hair, at least compared to all other primates? At Smithsonian, Jason Daley shares the latest genetic research on the biological factors that result in humans' minimal body hair and its unusual distribution. Daley also surveys the fascinating current theories about why we evolved into the only naked apes. From Smithsonian:

One popular idea that has gone in and out of favor since it was proposed is called the aquatic ape theory. The hypothesis suggests that human ancestors lived on the savannahs of Africa, gathering and hunting prey. But during the dry season, they would move to oases and lakesides and wade into shallow waters to collect aquatic tubers, shellfish or other food sources. The hypothesis suggests that, since hair is not a very good insulator in water, our species traded in most of our fur for a layer of fat. The hypothesis even suggests we might have developed bipedalism to become more effective waders. But this idea, which has been around for decades, hasn’t received much support from the fossil record and isn’t taken seriously by most researchers.

A more widely accepted theory is that, when human ancestors moved from the cool shady forests into the savannah, they needed better thermoregulation. Losing all that fur made it possible for hominins to hunt during the day in the hot grasslands without overheating. An increase in sweat glands, many more than other primates, also kept early humans on the cool side. The development of fire and clothing meant that humans could keep cool during the day and cozy up at night.

Tyrannosaurus rex is known for being huge and threatening. What's with those tiny arms though? Don't call them useless.

Read the rest

YouTuber Retic over at Prehistoric Pets TV has a huge collection of pythons and other ancient creatures. Here he shows how and why a clutch of python eggs can be lifted up in giant sticky clumps. Read the rest

Yeast has brought a lot of joy into the world, but its evolutionary origins were unclear until scientists did a worldwide genomic survey of the humble organism. Based on the genetic diversity of strains found in China, they concluded that its origin is almost certainly in that part of the world. Read the rest

Squid ancestors were happy creatures with shells until about 400 million years ago, when the emergence of fish with jaws set off an evolutionary arms race between fish and cephalopods. Read the rest

Matt Baker from UsefulCharts.com made a detailed poster and video of how the English alphabet evolved over the last 4,000 years, but his elegant and colorful topline is the simplest iteration of the process: Read the rest

It's long been known that birds possess magnetoreception, or ability to sense earth's magnetic fields. Now researchers are narrowing down a specific eye protein called Cry4 that appears to allow birds to sense magnetic waves in the presence of blue light. Read the rest

Turtles were at the center of a hundred-year evolutionary controversy since the 1887 discovery of a Proganochelys fossil in Germany. AS PBS Eons explains, the question of how turtles got their shells led scientists "to rethink the entire history of reptile evolution." Read the rest

Fun fact: trilobites were able to see thanks to eyes made of calcite instead of soft tissue. YouTuber Thunderf00t shows off a cool fossil and explains the phenomenon. Read the rest

The EVO evolution webshop offers this fantastic flipbook of human evolution. It's €7.50.

(via /r/educationalgifs) Read the rest

In many, animal species are domesticated when humans bring them into their homes whether they want to be there or not. For example, it's mostly accepted that humans domesticated wolves, breeding them in captivity until they became the modern dogs we love today. Now, a new study of cat genetics reveals that cats just kind of hung around humans for thousands of years before they were domesticated. From Casey Smith's article in National Geographic:

The earlier ancestors of today’s domestic cats spread from southwest Asia and into Europe as early as 4400 B.C. The cats likely started hanging around farming communities in the Fertile Crescent about 8,000 years ago, where they settled into a mutually beneficial relationship as humans’ rodent patrol.

Mice and rats were attracted to crops and other agricultural byproducts being produced by human civilizations. Cats likely followed the rodent populations and, in turn, frequently approached the human settlements.

“This is probably how the first encounter between humans and cats occurred,” says study coauthor Claudio Ottoni of the University of Leuven. “It’s not that humans took some cats and put them inside cages,” he says. Instead, people more or less allowed cats to domesticate themselves.

A second lineage, consisting of African cats that dominated Egypt, spread into the Mediterranean and most of the Old World beginning around 1500 B.C. This Egyptian cat probably had behaviors that made it attractive to humans, such as sociability and tameness.

The results suggest that prehistoric human populations probably began carrying their cats along ancient land and sea trade routes to control rodents.

Research suggests that people who do nice things for others, often at a cost for themselves, are more sexually attractive. From an evolutionary perspective, this might be because altruism indicates that a potential mate is more cooperative and caring. Evolutionary psychologists Steven Arnocky, at Nipissing University, and Pat Barclay, at the University of Guelph, conducted a fascinating study to explore whether altruistic people really do have more sexual partners. From Scientific American:

This theory suggests that altruism may serve, in part, to convey one’s value as a mating partner, including one’s concern for others and likelihood of cooperating with future mates. Research has shown that we prefer altruistic partners, all else being equal; especially for long-term mating (the evidence for altruism being preferred in short-term mates is mixed). Not surprisingly, then, the pull to demonstrate one’s altruism can be strong. Some research has shown that men will actively compete with one another (termed competitive altruism) by making charitable donations to women. Interestingly, these charitable donations increase when the target of one’s altruism is physically attractive...

Previous findings from hunter-gatherer populations have shown that men who hunt and share meat often enjoy greater reproductive access to women. But do these links hold up in other cultural and contextual arenas, such as in contemporary North American society? To find out, we conducted a set of two studies. In our first study, undergraduate men and women completed an altruism questionnaire (involving questions like “I have donated blood”), along with a sexual history survey. Participants also completed a personality inventory, given the possibility that those with certain personality characteristics (such as being extroverted) might happen to engage in both more altruism and more sexual activity.

Craig Froehle tracks the odd convolutions of his famous illustration of how conservatives and liberals view the notion of equality. It's been simplified, expanded, twisted, tucked in and turned inside-out—and even redrawn by professional artists.

Are the worst versions the ones that bury the simple point in condescending explanation?

Or the ones that seek to subvert it entirely, in as much as stamping "THIS IS FUCKING STUPID" over it counts as subversion?

The cannier mutations contextualize it for local audiences:

I am giddy that my little graphic has helped so many people think about the issue of equity and has spawned so many conversations in just the past few years. I’m not upset by the many way it’s been reimagined. In fact, I’m delighted, because the modifications just make it that much more useful to people.

A paper published this summer looked into over 100 times humpbacks were observed disrupting orcas who are hunting, like these humpbacks trying to save a gray whale and calf. But why do they do it? Read the rest

Lucy, the famed Australopithecus afarensis, may have died from falling out of a tree 3.18 million years ago, according to new forensic analysis. This video explains the reasoning behind the hypothesis. Read the rest

See sample pages from this book at Wink.

Trees of Life: A Visual History of Evolution

by Theodore W. Pietsch

Johns Hopkins University Press

2013, 376 pages, 8 x 10 x 1.1 inches (softcover)

Starting at $22 Buy a copy on Amazon

The primary metaphor for visualizing evolution is as a tree. The trunk is the oldest ancestor species which branch off newer species, which branch further leaves of the newest species. Ever since Darwin, biologists have been drawing trees to attempt to capture the complexity of evolution in various domains. These evolutionary trees are not only scientifically useful, but works of art. Over the years, many approaches to the trees have been tried – some minimal, some ornate, some abstract. This tome collects the finest, most unusual, most beautiful evolutionary tree maps produced in the last 200 years. They not only inform biology, they are fantastic examples of great design.

Read the rest

Language Evolution Simulation is exactly that, showing words changing little by little as time passes in a tiny world with three islands. It's agent-based, which is to say that it models little computer folk interacting with one another to simulate the little mutations that add up over time.

Rules

If an agent intersects with another, selects a word from the own vocabulary and tells that. The neighborhood receives and adds that word into its vocabulary as

- Mutation of a vowel sound with 0.1 probability

- Mutation of a const sound with 0.1 probability

- Compounding with another word with 0.1 probability

- Without any mutation

There's nothing to do but watch words change, but it feels like the underpinning of a very strange computer game about culture.

I love agent-based models; check out this simulation of political cliques I made. It randomly generates several personalities, who then go around and bicker or flatter one another. It's very bland and primitive, made in Flash, and the "next turn" text is rather fiddly to click. But I've always had plans on expanding it into a more fully featured game.

Read the rest