“We have all seen the canonical parade of apes, each one becoming more human. We know that, as a depiction of evolution, this line-up is tosh. Yet we cling to it. Ideas of what human evolution ought to have been like still colour our debates.” So said Henry Gee, editor of Nature this month (478, 6 October 2011, page 34, doi:10.1038/478034a), Are other icons coloring scientists’ views of human origins? How close are they to describing scientifically where we come from?
Debates over microevolution: In PNAS this month, Milot et al. (October 3, 2011, doi: 10.1073/pnas.1104210108) claim to have found evidence of microevolution in a modern human population. The first line of their abstract indicates that another debate rages among secular anthropologists. “It is often claimed that modern humans have stopped evolving because cultural and technological advancements have annihilated natural selection. In contrast, recent studies show that selection can be strong in contemporary populations. However, detecting a response to selection is particularly challenging,” they said. What they claimed to find is a change in age of first reproduction in French Canadian women over the last 140 years. This begs the question whether cultural changes can also contribute to genetic changes. Their last line indicates that they realize other causes than natural selection may be responsible: “Our results show that microevolution can be detectable over relatively few generations in humans and underscore the need for studies of human demography and reproductive ecology to consider the role of evolutionary processes.”
Debates over Homo: Fred Spoor, weighing in on the recent Australopithecus sediba controversy in Nature (478, 06 October 2011, pp. 44–45, doi:10.1038/478044a), mentioned “debate” several times: (1) Berger’s fossils “open up a debate about the origins of the genus Homo,” (2) Berger’s “idea that no fossil older than 2.0 Myr is legitimately attributable to Homo is highly debatable — the arguments provided in the paper are insufficiently specific to be conclusive,” Spoor said; (3) “The interpretation of their findings may be a matter of debate,” he ended. He never quite clarified the breadth of the debate.
Sugar man: The new icon of human evolution may have to include a member eating a candy bar. “‘Sugary’ Mutation May Have Led to Humans’ Rise,” announced Science Daily. A look into the article reveals a completely different claim, however. A loss mutation in the ability to produce a certain sugar, scientists at UC San Diego claim, helped early hominids diverge from great apes. From then on, did the lineup of human evolution occur that Henry Gee described as tosh?
Start over: “It’s impossible to pinpoint the moment when a paradigm shifts. But when it comes to views of the origin of Homo sapiens, last month may be as good a time as any,” wrote Ann Gibbons in Science this month (14 October 2011: Vol. 334 no. 6053 p. 167, doi:10.1126/science.334.6053.167). She was speaking of the revolutionary claim that Denisovans and Neanderthals appear to have interbred with modern humans. She quotes Chris Stringer saying, “Africa doesn’t have a simple story of modern humans appearing and everything else disappearing.” That marks “a turning point in views of modern human origins,” Gibbons demonstrated with other expert opinions: “‘Indeed, “if interbreeding happened outside of Africa,’ as the complete genomes of Neandertals and Denisovans suggest, ‘it is quite likely it also happened within Africa,’ says population geneticist Laurent Excoffier of the University of Bern in Switzerland.” Interbreeding is a sign all these varieties of humans were members of a single species.
He was what he ate: A headline on Science Daily reads,“New Technologies Challenge Old Ideas About Early Hominid Diets.” Surprise: Nutcracker Man didn’t crack nuts. That’s not all: “New assessments by researchers using the latest high-tech tools to study the diets of early hominids are challenging long-held assumptions about what our ancestors ate,” if indeed the ape-like creatures Paranthropus boisei were ancestral to humans. “….Such findings are forcing anthropologists to rethink long-held assumptions about early hominids,” it continued, raising questions about what long-held assumptions today are immune from radical rethinking. How radical? Matt Sponheimer from the University of Colorado said, “It is also clear that our previous notions of this group’s diet were grossly oversimplified at best, and absolutely backward at worst…. The bottom line is that our old answers about hominid diets are no longer sufficient, and we really need to start looking in directions that would have been considered crazy even a decade ago.” He did not consider whether the notion that these creatures are ancestral to humans might someday be considered backward or crazy. Given their own words, such upsets appear conceivable.
Ochre on the half shell: Live Science has a photo of an abalone shell that appears to have been used like a mortar and pestle for working some reddish compound long, long ago. “The mixture may have been used as a paint or adhesive,” the caption reads, indicating the cosmetics industry got an early start at 100,000 years ago. “It’s the oldest evidence of humans making a complex compound, and even the oldest evidence of humans using containers.” Found in Blombos Cave, South Africa, the shells show presence of toolkits for working materials. “No matter what the use of the compound, Henshilwood and Wadley agree that its existence reveals that our ancient ancestors were a clever bunch,” the article ended. “The hunter-gatherers knew what to collect to make the paint, and they transported the ocher from 12 miles (20 km) away, suggesting smart planning.” Now hear this: “In fact, Henshilwood said, the oil-pigment-and-binders mixture they created was almost the same as paint recipes used in ancient Egypt only a few thousand years ago.” Imagine that; no improvement in this technology for 95,000 years – by a clever bunch.
Teacher influence: In a video interview on Live Science, Curtis Maren describes how he was inspired to become a paleoanthropologist by old black-and-white films of Louis and Mary Leakey looking for human origins in Africa (little of whose views remain intact). Maren now looks for evidence of the evolution of human brain power in Greece. “In 2007, Marean and a team of researchers reported finding evidence at Pinnacle Point that suggests humans may have eaten seafood more than 40,000 years earlier than previous estimates and it may have been a catalyst for early human migration out of Africa,” the article said. “In 2009, Marean and colleagues reported finding evidence from this location that early modern humans used fire in a controlled way to increase the quality and efficiency of stone tools, possibly a sign of the evolution of human brain power.” Claiming that science is self-correcting (see previous entry), and that his methods are equivalent to those of physicists who do rocket science, Marean claims that paleoanthropologists need to have a high value of ethics, does not explain how ethics evolved. He does, however, underscore several paradigm shifts he is aware of. Now Marean, a hard rock devotee, influences young people himself.
Cave men discovered: According to PhysOrg, five living cave men have emerged from a cave in Sardinia. They were astronauts from the ESA (European Space Agency), undergoing a test of isolation from familiar day-night cycles for six days. As scientists, they demonstrated that human intelligence is not necessarily correlated with habitat.
Reading the stuff that evolutionary paleoanthropologists crank out is both entertaining and exasperating. They are like the blind men and the elephant, taking their partial evidence and weaving grand tales (or tails) out of them. One of the major icons of evolution, the line-up of human evolution from dancing ape to Man the Wise, was described by Henry Gee as tosh. Tosh means bosh. Bosh means nonsense. That means that for decades, school children were taught nonsense, bosh, tosh. Omigosh, they were awash in bosh, learning tosh with panache. Do you have any confidence, dear reader, that these blind men called paleoanthropologists, so self-admittedly clueless and subject to crazy paradigm shifts, are capable of coming up with a unified theory of elephant?