Laelaps has an excellent post up, Evolution's Arrow, which you should read. Set some time aside, it is long. I don't know enough about paleontology to comment with great insight on the many of the topics which Laelaps alludes to, and some of them get a bit philosophical for my own taste (that is, issues turn on the interpretation of words), but there is one point which I might assert is somewhat muddy:
...Looking at the hominid evolutionary bush pictured below [see here, it's clear that we are but a single surviving twig of a group that once had a much greater diversity, australopithecines (including the "robust" forms in Paranthropus) seeming to be a much more successful type of hominid even if they are presently extinct. Given that our own species has only been in its modern form for little more than 200,000 years and we are daily poisoning our ...
