Birds are not dinosaurs (simplified)

Having bought a bunch of bargin bin books at Borders on the study of dinosaurs, most seem to state that birds are descended(sp?) from dinosaurs or even ARE a form of dinosaur.

The evidence they site as why some people say it isn’t so is weak compared to why they are.

After looking on the internet the only arguments I can find against birds being descendents of dinosaurs are very technical.

So what is the SD? Does anyone have a layman’s version of why birds are not descended from dinosaurs.

Two points of contention are generally at the root of the “birds-are-not-dinosaur-descnedants” philosophy:

  1. Cladistics, the taxonomic method which establishes nested hiearchies based on shared, derived characters, and which establishes birds, not only as dinosaur descendants, but as dinosaurs by definition, is flawed.
  2. The most bird-like theropods (the bipedal mostly-carnivores) are found in strata that post-date Archaeopteryx, rather than pre-date it.

Two primary proponents of the non-dinosaurian origin of birds are J. Alan Feduccia and Larry Martin. You can probably find much more detail by trying to look up some info from either of those two authors. George Olshevsky also detailed (in allegedly layman’s terms) his BCF (Birds Came First) theory in the June 1994 issue of Omni magazine (I do not have a copy of this, nor have I seen it, so I can’t say much about it).