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Natural selection is nothing more than differential reproduction due to heritable variation. Differential reproduction just means that some will (may) out-reproduce others. And if that differential reproduction is due to some heritable variation then you have natural selection. The heritable variation doesn't even have to be genetic as behavioral characteristics can be passed down also.
And all of that depends on the environment as what is beneficial or working good enough in one environment may not be beneficial nor working good enough in another environment.
And that brings us to another point- whatever works "good enough" gets kept as natural selection basically eliminates that which doesn't work good enough.
Does natural selection have a direction? Only if survivability is a direction.
What is selection? Quite simply, it is what Darwin called selection any time an organism lives long enough to procreate. Let me be as clear as possible here: Selection is a RESULT, not a cause. As such, it cannot be credited with causing anything constructive.
ReplyDeleteYou cant select what is not on the menu, so anything at all, be it a giant step or a baby step, must exist before it can be selected. The question is arrival of the fittest, not survival, however. What caused an improved trait to exist PRE-selection is the important question.
Selection is a subtractive filter, wholly incapable of creation, but fully capable of destruction. A filter will find gold in a river only if it already is there. It can not help create gold if it isnt there.
Selection can be used to explain extinction or death, and it can be poorly used as a weak excuse why living things have no random formations. But it cannot be used to explain any novel species or trait. It can only explain why that individual didnt die.
But Darwin didnt write a book called "Extinction of Species".
Failure to die (selection) can not cause life. To use selection to explain evolution is to say "We live because we didnt die". A silly childhood joke turned into a theory we teach in schools as if it were fact.
Selection, as Darwin coined it, is the passive act of not dying. It has no positive effect on evolution whatsoever.