kottke.org posts about humans
In the last few years, scientists have discovered that before Neanderthals went extinct around 30,000 years ago, they interbred with modern humans. As a result, many humans alive today contain Neanderthal DNA in their genomes, typically between 1-4%.
Yesterday, a few of the editors at The Atlantic had their genes analyzed for Neanderthal DNA: Alexis Madrigal had 3.6%, Steve Clemons had 4.3%, and James Fallows had 5%. Personal genetic information company 23andMe added the ability to determine your Neanderthal DNA percentage a few months ago and it turns out 2.7% of my DNA is from Neanderthals, compared to 2.5% for the average 23andMe user.
If you have a 23andMe acct, you can check your percentage by logging in and going to "Ancestry Labs" in the sidebar.
Elephants were the "perfect food package" for pre-human hominids (they were slow with a good fat-to-protein ratio) and their extinction in the Middle East (and Africa) caused those hominids to evolve to be more like modern humans.
When elephants began to die out, Homo erectus "needed to hunt many smaller, more evasive animals. Energy requirements increased, but with plant and protein intake limited, the source had to come from fat. He had to become calculated about hunting," Ben-Dor says, noting that this change is evident in the physical appearance of modern humans, lighter than Homo erectus and with larger brains.
(via @daveg)
Whoa, watch the video at the top of this article to see how the human face develops in the womb from an age of one-month to ten weeks. It all just comes together right at the end!
If you watch it closely, you will see that the human face is actually formed of three main sections which rotate and come together in an unborn foetus.
The way this happens only really makes sense when you realise that, strange though it may sound, we are actually descended from fish.
The early human embryo looks very similar to the embryo of any other mammal, bird or amphibian -- all of which have evolved from fish.
Your eyes start out on the sides of your head, but then move to the middle.
The top lip along with the jaw and palate started life as gill-like structures on your neck. Your nostrils and the middle part of your lip come down from the top of your head.
There is no trace of a scar; the plates of tissue and muscle fuse seamlessly. But there is, however, a little remnant of all this activity in the middle of your top lip -- your philtrum.
(via hypertext)
The discovery of stone tools that are possibly 130,000 years old on the island of Crete may indicate that humans were seafaring far earlier than is commonly believed.
Archaeologists and experts on early nautical history said the discovery appeared to show that these surprisingly ancient mariners had craft sturdier and more reliable than rafts. They also must have had the cognitive ability to conceive and carry out repeated water crossing over great distances in order to establish sustainable populations producing an abundance of stone artifacts.
Internet, meet Ardi, the newest member of the human branch of the primate family tree.
Or rather, the oldest. Discovered in Ethiopia in 1994, Ardi is a 4.4 million-year-old partial skeleton of a female Ardipithecus ramidus.
The fossil puts to rest the notion, popular since Darwin's time, that a chimpanzee-like missing link -- resembling something between humans and today's apes -- would eventually be found at the root of the human family tree. Indeed, the new evidence suggests that the study of chimpanzee anatomy and behavior -- long used to infer the nature of the earliest human ancestors -- is largely irrelevant to understanding our beginnings.
Ardi instead shows an unexpected mix of advanced characteristics and of primitive traits seen in much older apes that were unlike chimps or gorillas. As such, the skeleton offers a window on what the last common ancestor of humans and living apes might have been like.
This is a major discovery; Science is devoting a special issue to the find with 11 detailed peer-review papers and general summaries. I expect we'll be hearing more about this in the coming weeks as all that science filters through the lay media. (thx, jeff)
Some poop in a cave in Oregon has been dated to more than 14,000 years ago and identified as human, adding to other evidence that humans inhabited the Americas before the well-known Clovis people.
Other archaeologists agreed that the findings established more firmly than before the presence of people on the continent at least 1,000 years before the well-known Clovis people, previously thought to be the first Americans. Recent research at sites in Florida and Wisconsin also appears to support the earlier arrivals, and a campsite in Chile indicates migration deep into South America by 14,600 years ago.
Speaking of memes, Susan Blackmore theorizes that humans are just machines for propagating them.
Memes are using human brains as their copying machinery. So we need to understand the way human beings work.
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Up until very recently in the world of memes, humans did all the varying and selecting. We had machines that copied -- photocopiers, printing presses -- but only very recently do we have artificial machines that also produce the variations, for example (software that) mixes up ideas and produces an essay or neural networks that produce new music and do the selecting. There are machines that will choose which music you listen to. It's all shifting that way because evolution by natural selection is inevitable. There's a shift to the machines doing all of that.
When asked what the future will look like, she says, "it will look like humans are just a minor thing on this planet with masses (of) silicon-based machinery using us to drag stuff out of the ground to build more machines."
Good times.
The pace of human evolution has accelerated greatly over the last 40,000 years, partially due to our population growth.
The brisk rate of human selection occurred for two reasons, Dr. Moyzis' team says. One was that the population started to grow, first in Africa and then in the rest of the world after the first modern humans left Africa. The larger size of the population meant that there were more mutations for natural selection to work on. The second reason for the accelerated evolution was that the expanding human populations in Africa and Eurasia were encountering climates and diseases to which they had to adapt genetically. The extra mutations in their growing populations allowed them to do so.
Dr. Moyzis said it was widely assumed that once people developed culture, they protected themselves from the environment and from the forces of natural selection. But people also had to adapt to the environments that their culture created, and the new analysis shows that evolution continued even faster than before.
Looks like this study answers the "Is Evolution Over?" question.
A timeline of human history (mostly sex and violence) by Milo Manara. NSFW.
Some recent research on the wrist bones of the so-called hobbit skeleton suggests that Flores man is an ancestor of modern humans and not just diseased homo sapiens. The debate continues. (via npr)
Humans are the animal world's best distance runners...we can run long distances relatively fast without overheating. "Once humans start running, it only takes a bit more energy for us to run faster, Lieberman said. Other animals, on the other hand, expend a lot more energy as they speed up, particularly when they switch from a trot to a gallop, which most animals cannot maintain over long distances." (via beebo)
I thought that said "Netherlanders"...I was ready to put that in the "odd things I didn't know about the Dutch" column.
An evolutionary theorist has predicted that humans may split into two sub-species: "the genetic upper class would be tall, slim, healthy, attractive, intelligent, and creative and a far cry from the 'underclass' humans who would have evolved into dim-witted, ugly, squat goblin-like creatures."
Watched America's Stone Age Explorers on PBS this evening, a summary of recent findings about who the first Americans were, where they came from, and when they arrived. Recent genetic and archeological evidence suggests they arrived earlier than generally accepted and may have originated from Europe rather than Asia.
Recently discovered human remains suggest that metrosexuals lived in Iron Age Ireland. One man's fingernails were manicured and his hands indicated he'd never done manual labor while the other wore hair gel imported from France and Spain. No word on if they wore their shirts tucked or untucked.
Further discovery of Homo floresiensis bones have strengthened researchers' argument that the so-called Hobbit is a new and distinct human species. More on Flores man at Nature, which is doing a weekly podcast now.
A US antropologist says that weaker toes found in human skeletons from 26,000-40,000 years ago indicates when humans started wearing sturdy shoes.
Robotics research suggests that Lucy walked upright like humans. Lucy, discovered in 1974 in Ethiopia, is a 3.2 million year old Australopithecus afarensis skeleton.
40,000 year-old human footprints found in Mexico. Humans are thought to have come to the Americas only 11,000 years ago.
