“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?….
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