The new revolution of human evolution.

Has anyone read this article yet? Researchers from Germany's Max Planck Institute for Evolutionary Anthropology are finding better ways to discover where humans have taken "turns", sort of speak, in our evolutionary history. It says that now instead of, using skull size, and bone structure to pin point differences in our evolutionary history, they can now use the differences found in the history of D.N.A. Their initial approach was to figure out when it was that humans transfered from hairy bodies, to wearing clothes. Through research into the D.N.A. of head lice, they found a "fork" in the louse's family tree that dates back about 114,000 years ago. They mention that body lice are apart from head lice and that body lice actually live on clothes not body hair.

Since new kinds of creatures tend to appear when a new habitat does, that's when human ancestors must have lost their body hair for good—and made up for it with clothing that, besides keeping them warm, provided a home for the newly evolved louse.

With the continued use of D.N.A. as a tool, this could really change what humans thought about our ancestral past. The article goes on to state that human origins are more complicated than biblical scripture dictates, and yet more complex than what science has discovered through time.

By analyzing the DNA of today's humans as well as chimps and other species (even lice), scientists are zeroing in on turning points in evolution, such as when and how language and speech developed, and when our ancestors left Africa. DNA can even reveal how many pilgrims made that trek. At the new Hall of Human Origins at the American Museum of Natural History in New York, DNA gets equal billing with fossils. And by comparing the impressions that brains left on the inside of skulls, "paleoneurology" is documenting when structures that power the human mind arose, shedding light on how our ancestors lived and thought. Whether or not you believe the hand of God was guiding these changes, the discoveries are overturning longstanding ideas about how we became human.

It seems that we as humans have branched off different lineages of ancestors though out the world. These ancestors spread out, but for reasons not exactly known, most likely difficulty in adaptation, a lot of these lineages died out. Our history shows that we as humans, have many changes to our evolution, and many times where there has been no change at all for a really long time.

Our species' travels through time proceeded in fits and starts, with long periods when "nothing much happened," punctuated by bursts of dizzying change, says paleontologist Ian Tattersall, co-curator of the American Museum's new hall.

Now with this new approach, newer technology, humans are discovering more about our origins, as these scientists speculate that we might even be able to pinpoint when it is that human and chimp lineages have split. Actually they think they already have.

Human DNA and chimp DNA differ by no more than 1.2 percent, and DNA changes at a fairly regular rate. That lets scientists use this rate to calibrate a "molecular clock" whose tick-tocks measure how long ago a genetic change occurred. The fact that the DNA of living chimps and humans differ by about 35 million chemical "letters," for instance, implies that the two lineages split 5 million to 6 million years ago.

The article also states that this discovery coincides with another discovery that the planet become very cold, and very dry about that same time. If during this time, temperatures and moisture dropped, some of the species of chimps that were roaming about might have ventured off into different locations were overall conditions varied from their original homes. These species of chimps might have been the ones to take first steps into becoming humans.

Now the contentious part. In 2001, a team digging in Chad unearthed what it claimed was the oldest fossil of an ancestor of humans but not chimps. If so, it must have lived after the two lineages split. Trouble was, Sahelanthropus tchadensis (nicknamed Toumai, the local word for "child") lived close to 7 million years ago. The genetic data, pointing to a human-chimp split at least 1 million years later, suggest that Toumai is not the ur-hominid—the first creature ancestral only to human and not our chimp cousins—after all.

With this discovery, Toumai has shown the world that human evolution is tricky in the sense that, traits, scientists used to think were unique and remained in tact for later generations in the evolution, actually disappeared and reappeared as it was fit for the species' environment. This rethinks the idea that certain characteristics found in fossils, do not necessarily give evidence that fossils succeed each other according to these traits. Meaning that these traits do not necessarily support direct lineage with humanity. This goes back to the idea stated before that different lineages of ancestral humans have died out, and some of them have survived, all the while having similar characteristics.

Last summer scientists discovered a gene called HAR1 (for human accelerated region) that is present in animals from chickens to chimps to people. It had changed in only two of its 118 chemical "letters" from 310 million years ago (when the lineages of chickens and chimps split) to 5 million years ago. But 18 letters changed in the (relative) blink of an eye since the human lineage split from chimps', Katherine Pollard of the University of California, Davis, and colleagues reported. That high rate of change is a sign of a gene whose evolution keeps conferring advantages on those who carry it, perhaps starting with Australopithecus. The brain, more than any other organ, may have reaped those genetic advantages. HAR1 reaches a peak of activity from the seventh to ninth week of gestation in humans, apparently spurring brain growth. And it is plentiful in cells that create the six layers of neurons in the human cortex. "HAR1 is present in neurons that play a role in the geometry and layout of the cortex," says Pollard. It likely helped the cortexes of our ancestors develop the elaborate folds characteristic of a complex brain.

With these advancements in genome research, scientists have also found that combined with other chemicals in the brain, the genes that influence connection speed within neurons had only started to emerge parallel to the emergence of Australopithecus. This gene activity is important in regulating cells that enhance learning, memory, and the promotion of brain growth.

And it helps explain why Lucy's kind were the way they were. Afarensis women and men stood three to five feet tall and weighed 60 to 100 pounds. They had small teeth good for fruits and nuts, but not meat. (The available prey was enough to make one a confirmed vegetarian: hyenas the size of bears, saber-toothed cats and other mega-reptiles and raptors.) That suggests that early humans were more often prey than predators, says anthropologist Robert Sussman of Washington University, coauthor of the 2005 book "Man the Hunted." The evidence is as stark as the many fossil skulls containing holes made by big cats and talon marks from raptors.

Kind of makes you think what it must have been like to be lower down the food chain. The article continues, that the idea of humans achieving evolutionary success through the development of weapons and hunting skills, is being disproved because of these new findings to the genome structure of our ancestral lineages. Our success seems to have been shaped more on the idea that social skills, and brain activity such as wits and ideas, played a more crucial role.

Both genetics and paleoneurology back that up. A hormone called oxytocin, best-known for inducing labor and lactation in women, also operates in the brain (of both sexes). There, it promotes trust during interactions with other people, and thus the cooperative behavior that lets groups of people live together for the common good. By comparing the chimp genome with the human, scientists infer that oxytocin existed in the ancestor of both. But it has undergone changes since then, perhaps in how strongly the brain responds to it and in how much is produced. The research is still underway, but one possibility is that the changes occurred around the time our ancestors settled into a system based on enduring bonds between men and women, about 1.7 million years ago.

As the article continues, it is revealed that brain size is not necessarily the safest way to go when predicting whether or not our ancestral lineages where actually very successful. Brain structure still seems to play a greater role in advancement of the species. The development of an asymmetric brain was key in the evolution of humans, as this same asymmetry is still present in humans to this day.

Asymmetry is a mark of increasing specialization and therefore complex cognitive ability. Erectus used it to, among other things, discover and tame fire. What they did not use it for is technology. Tools found with the Dmanisi fossils include cutting flakes, rock "cores" from which flakes were made and a chopper, all primitive even for their time. "The old idea that you needed a master's degree in stone tools to leave Africa is crazy," says Bernard Wood.

Really? Is it really that crazy!? Seriously though, Homo erectus spread throughout Europe and Asia (Eurasia) about 2,000,000 years ago but that it is arguable as to whether or not they are direct ancestors to humans. The initial idea was that Homo erectus scattered throughout the world and with the same genetic mutations, and adaptations, all the groups were able to become Homo sapiens. This idea is contradicted in the sense that the Y chromosome present in our genetic make up remains essentially complete as it is passed on from male generation to generation. Well that is incorrect, it remains mostly complete as there has been certain changes throughout it's evolution. These changes then are passed on to all males of the future generations.

Peter Underhill, a molecular anthropologist at Stanford University, tracked 160 such changes in the Y's of 1,062 men from 21 populations across the world. Applying the molecular-clock technique, he concludes that the most recent common ancestor of all men alive today lived 89,000 years ago in Africa. The first modern humans—and therefore, unlike the earlier wave of Homo erectus into Asia a million years ago, the ancestors of everyone today—departed Africa about 66,000 years ago.

Wow! I have found you grandpapa! It seems that these descendants of ours were actually few and far between, more or less 4,000 according to the combinations in the chromosomes. Yet what makes this even more interesting is that not until about 50,000 years ago we start to see, through the discovery of arts and crafts, a cognitive advance. This could have been in the form of language development or memory development. It is obvious that the structure of the brain played a bigger role in the emergence of these clues and not the actual size of the brain. When did these changes to the structure of the brain occur? Well the article states that researches have found three changes that fit the timeline.

The first, called FOXP2, plays a role in human speech and language, but it must do something else in other species, because the decidedly nonverbal mouse has a version of it. Using the standard molecular-clock tactic, Svante Paabo and colleagues at the Max Planck Institute estimate that the human version of FOXP2 appeared less than 200,000 years ago—about when anatomically modern humans stepped onto the world stage—and maybe as recently as 50,000. If so, then it is only humans as modern as those in the last diaspora out of Africa who developed advanced, spoken language. Another gene with interesting timing is microcephalin, which affects brain size. It carries a time stamp of 37,000 years ago, again when symbolic thinking was taking hold in our most recent ancestors. The third, called ASPM and also involved in brain size, clocks in at 5,800 years. That was just before people established the first cities in the Near East and is well after Homo sapiens attained their modern form. It therefore suggests that we are still evolving.

Well, phew. That was interesting! All I ask is, if we are still evolving, which is pretty obvious, how will we look like in the future? Of course it depends on our environment, but, really think. How will we look if their is an ice age? What if the world floods. Will we have to adapt to the water? What if the warming of the planet continues? Also, how does this discovery effect established religion? Could these changes in our D.N.A. to adapt, actually be the hand of god? Are we tapping into evidence that if God created us, he has constantly been manipulating our D.N.A. to fit our environment? What about the bible saying that the universe and humanity were created in days? Anyway, the original source is at the bottom. Enjoy!

Beyond Stones and Bones

Excellent set of articles and interesting analysis! I want to come back and read it more thoroughly, because you do raise some intriguing points.

But, as you say in your summary, it's impossible to predict where we will go, because unlike so many other creatures, we can change the conditions to suit ourselves. People survive today who would never have survived beyond birth a hundred years ago.