evolution

[Mr.Lizard]

I've read a few books by Gould. He has a lot of intriguing evidence and ideas. His ideas on punctuated equilibrium make a lot of sense...more sense to me than the inexorable change of one species into a new and improved form.
Personally,I believe in the idea of genetic memory and that genetic memory is responsible for "taking notes" on the environment,making an evaluation of it and then using this evaluation as a blueprint with which to build new structures or modify existing ones to perform new tasks.
There is a vast storehouse of genetic combinations previously used in the the organism's ancient ancestry with which it can use to redesign or invent with.
This same idea applies in the far more rapid and fluid evolution of someone's mind. You collect memories all throughout your life and use these memories collectively to form new ideas---using these ideas you can build and invent what you can conceive.
One of Gould's books---"Hen's Teeth and Horse's Toes" talks about the collection of characteristics stored in this genetic warehouse. The book's title refers to the ability of organisms to draw upon ancestral characteristics,for the better or otherwise.
In the book he describes how unborn chicks can be induced to grow teeth simply by providing them with the necessary material.
The blueprint already exists,merely the material required for making teeth was not needed for any other reason than teeth so it was given up-----"use it or lose it". In fact,early species of birds did have teeth,hesperornis( a diving bird),archeopteryx and others. Another interesting characteristic of some birds is their ability to grow claws on their wings similar in at least one species to archeopteryx. The hoatzin of S. America,as a juvenile nesting in the trees over rivers is provided with these claws with which it climbs up the tree when it has fallen out or fled it's nest.
As the bird matures and becomes capable of flight these fingers are absorbed by the body. Interestingly enough,you can still find a vestigial thumb claw on a plucked chichen wing. While the other four fingers have become fused.Unlike the teeth,the material for making the thumb claw is still in use to produce claws upon the feet. Note also the retained clasper claws in some boids.
The horse also retains an unused "thumb" which can be seen on the inside of the foreleg. In rare instances known as atavisms,this other toe is present next to the single toe which the horse walks upon.This goes back to the horse's ancestry when it was once used. In fact,at some point in embryonic developement five digits can be discerned in many vertebrate species...pigs,whales,birds.
Sorry if I digressed a bit,one of my favorite subjects is the mechanism of evolution.
Some other good reads are "Jurassic Park" and the "Lost World" by Michael Crichton.They're sci-fi of course but there's a lot of real science put into these books. H.G. Wells' "Time Machine" is another on which touches on evolution a bit.

--Kevin--

[Crotalus75]

I like the genetic memory idea. Organisms have a large percentage of DNA that is not used to code for proteins (introns). Wouldn't it be interesting to find that these unused portions had some role in evolution and adaptation by holding necessary genetic information? Just a stray thought.