Evolution (Introduction)

by dhw, Friday, October 09, 2009, 13:01 (5523 days ago) @ David Turell

I'm not sure how excited we should be about Ardi, which my newspaper dubbed our "oldest ancestor" ... the same title that was given to Lucy, and will also be given to the next sensational discovery. I can well understand the thrill of the find, but can we really learn that much? Ardi lived in a social group, was an upright walker, had long arms, spent a lot of her time in the trees, and had a relatively small brain. But hold on. Lucy lived in a social group, was an upright walker, had long arms, spent a lot of her time in the trees, and had a relatively small brain. Is it so surprising that a creature in our direct line lived in a social group and walked upright, that tree-dwellers had long arms, and that until the brain became larger, it was smaller? -It's true that 4.4 million years takes us back a lot further than Lucy. But Ardi had a mummy and daddy, who by definition were also our ancestors, and didn't they have their ancestors, and they theirs, all the way back to Little Minnie Molecule? If Evolution is correct, all creatures have common ancestors, and no-one knows just where the paths separated. Tim White, professor of human evolution at Berkeley, who is hoping to find the "last common ancestor", says: "We haven't found it, but we've come closer than we've ever come, at 4.4.million years ago." Well, yes, 4.4 million is closer than 3.2 million, but even if chimps and humans did diverge from a pre-Ardi hominid, how can we ever be sure we've found the last common ancestor, since no-one can possibly know what has NOT been discovered?-Chris Stringer, head of human origins at the Natural History Museum, London, is quoted as saying: "The assumption among many researchers is that while humans have evolved a lot, chimps haven't changed much so we can use them as a model of the common ancestor we shared. But why shouldn't chimps have changed? Everything evolves. We are really trying to establish what set us off on our evolutionary path." Gerald Schroeder's God fiddling around? Ardi's great great grandparents having a little accident? One thing I'll guarantee: Ardi won't tell us.