a condition usually brought about by too little knowledge of a subject.

I have assumed for a long time that the Cretaceous Event did cause the extinction of dinosaurs, including T Rex and the Raptor family. Recently, we are reading that birds, (chickens ??), are evoived from T Rex, with their dna carrying recessive traits such as teeth and grasping appendages. A recent discussion on OT implied that we might someday recreate some dinosaur species by manipulating the dna of chickens.

If there is any truth to this, how does anything evolve from an extinct species? I would think that the original species would have had to survive in order to evolve into a smaller species that would eventually become the chicken or some other bird.

While the idea of T Rex surviving the extinction event by scavenging makes some sense, I have never seen speculation that they survived long enough to downsize and become birds. Therefore the only way it could happen is that the downsizing and evolving into bird form had been going on for a long time with the T Rex and the downsized, soon to be bird, species existing simultaneously prior to the extinction event.

I never thought of it working that way. I have always pictured evolutionary changes to be subtle and mutually exclusive, not a situation where the root species would exist side by side with the newly evolved (or nearly evolved) species.

I suppose when you have millions of years to work with a geneticist could explain it.