Just out of curiosity, can you provide an example of a specie that ever existed that no longer exists in any form--such as reptiles. There is a bit of bait-and-switch in most evolutionary discussions. No one debates whether species vary with environmental conditions. That's called adaptation. What's in question is whether one species can become another one. Can you provide even one example of that with evidence?
Hank
Reptiles aren't a species, Einstein, they're a class of vertebrates. There are many extinct classes of vertebrates. Placoderms and Acanthodines are good examples.
Olenellus gilberti
Smilodon fatalis
Bos primigenius