reply to post by Romantic_Rebel
I think we should leave the creationists and evolutionists to argue for a while about which is true and try and answer the question asked.
First, drop the notion that evolution of a species is a forward process aiming towards a goal, its not. Evolution has no goals, it is not a sentient
process.
Evolution is, at its simplest level, the changes made to life to better able it to survive in its current environment.
This statement can be broken down to feed, breed, and speed.
Before I go into that further, we do need a short discussion on genetics. And I intend, at least to start with, to keep it human.
The traits that make you who you are physically, colour of hair, hight and build, etc. are passed to you from your parents via the genes supplied by
the sperm and egg at conception. Some genes will have a greater effect on you than others so you may find that your father was built like a quarter
back and you inherit this gene from him and you too have a similar build. Your brother on the other hand finds that the gene responsible for his
build came from your mother who was more like tinker-bell.
In modern human society this would not have a huge effect on what I am about to posit.
Step back a few hundred thousand years. (Evolution is a VERY lengthy process) There is no civilised society to protect those less able to protect
themselves. The guy built like tinker-bell will find that he is less able to compete for the best food or breeding partners. Maybe less swift of foot
when escaping predators. (We havnt always been at the top of the food chain, and most of us dumped into a primitive era would quickly perish)
The upshot is that the "tinker-bell-ish guy would be less likely to survive long enough to breed and pass the dominant gene that controlled his
growth to any off spring.
In this fabricated scenario, only the genes for powerfully built humans would be passed on and the species, over time would evolve in to a race of
quarter backs.
There is however, a however. Evolution isn't quite as straight forward as that. Many , many factors come into play. Peacocks have huge fan like
tails that make flight very difficult and take off hard work, so why evolve that huge tail that could be detrimental in a survival situation?
This is a case of evolution by sexual selection. Female peahens, over generations have preferred to breed with the healthiest specimens possible, and
the perception of a healthy peacock is demonstrated by the personal resources it can expend in producing this fantastic display. And because the
female prefer to mate with this type of male, the gene for producing this huge flamboyant tail has been passed on, and on, and on.
What both of these scenarios demonstrate is that any gene that aids a species to be better at getting food, (feed) better at escaping predators,
(speed), in order to allow it produce offspring, (breed) will be passed onto the offspring.
And that bin a nutshell is evolution!
You will come across " the theory of evolution" and a lot of people will place the accent heavily on the word "theory" to try and prove that
evolution is un-proven. It is not, evolution is a fact. The mechanisms that lead to a species evolving are many and varied and some are just
theories. I can not prove that a peahen only wants to mate with a healthy, displaying peacock and therefore happily accept that " evolution by
sexual preference" is only a theory. But it is only the last two words that are theory. the first is fact.
If you really are interested, I fully recommend the "Ancestors Tale" by Richard Dawkins (now watch the creationist backlash) as an amazing insight
into the evolutionary process from single cell to all life on the plant.(actually it goes from all life on the planet to a single cell, but I'm being
pedantic.)
Hope this clarifies things a bit.
T'is late, ciao fer no