2011-05-24, 01:03 AM
Eosian Wrote:Genetic traits are not passed on as perfect copies, they mutate and variate generation by generation, creating new effects and the ones that survive get passed down. The ones that lessen the viability of life result in death and therefore do not get passed down (often), the rest do whether they're neutral or beneficial, with the more beneficial being more likely to persist and the neutral more likely to continue permuting.
It's not necessarily that we adapt to suit our environment, it's more than those who've developed adaptation more suitable to the environment have a better opportunity to pass on those traits until they become a subspecies unto themselves.
An easy example being green lizards. Lizards may spontaneously develop in other colors, red, blue, purple, but the ones who come up in green blend better with their environment. They didn't choose to be green to survive, they survived because they happened to be born green and the others didn't and therefore didn't live to pass on their genes. Green team won.
I understand natural selection, which was why the chameleon's example was used (to demonstrate pure natural selection vs a later example that reflects environmental adaptation). Else, my first sentence wouldn't claim that almost everything today exists because they simply by chance were "chosen" to.
I think the keyword in your post is "mutate". As I've only studied genetics with beans and flies, the genetic traits did in fact get passed on perfectly.
However, for things to change, there has to be change somewhere in the process. I'm aware of the ways through which genetic variation takes place, mutation and/or alteration in chromosome number/shape/size and such.
The thing I can't wrap my mind around is what exactly drives that variation? Is environmental condition a candidate? Is it just purely by chance (random mutation that happens regardless of any other factor, even time) and anyone lucky enough to be chosen to move on will continue breeding offsprings? Is it somewhere in the middle? And where?