"2 ) Just because something has changed from one age to the next , this does not necessarily mean that one begat the other ."
"Well , that was badly stated . But we 've been over this before and you still do n't seem to grasp . No one claims that any particular living animal is descended from any particular fossil . However , given the nature of life that we do observe , where we can see many species of equus , 36 species of cat , 28 species of canid , 8 or 10 species of bear ( with as many more extinct species ) , 850,000 species of beetle , and on and on , we conclude that life was similar in the past . And while we can look at a fossil species of theropod dinosaur and find many avian characteristics , we do not conclude that this fossil was ancestral to birds . But we know that there were probably many species of theropods that had avian characteristics , just like there are many animals with cat-like features . Recent discoveries are bearing out that conclusion . So we do n't say that this fossil is ancestral to that fossil or to this living organism . But we do say that this fossil shows characteristics that we would expect in an ancestral form . Thus , Archaeopteryx is not claimed to be ancestral to birds - in fact , is is believed to have eventually gone extinct ( in all three known species ) . What we do say is that Archaeopteryx shows characteristics of both theropod dinosaurs and birds . Is in one of a broad lineage of many species with such characteristics , at least one of which is ancestral to modern birds ( but we ca n't determine which one or ones that might be ) . And we have n't even gotten into the question of derived morphology . Why do n't we assume that dogs are descended from some very dog-like artiodactyl ? In fact , why do we conclude that these dog-like animals are , in fact , artiodactyls ?"
"Just because something has changed from one age to the next , this does not necessarily mean that one begat the other ."
"Well , that was badly stated"