Quote:
Originally posted by Neo
For example, you have genes that set a potential height, but environmental factors such as nutrition, exercise, etc can limit or cause height to exceed expectations.
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We're not talking about behaviours influenced by environment; we're talking about innate behaviour - as in possessed at birth (as per the definition). These monkeys in the study showed an innate fear of snakes that is related to both genetics and learning. We know that it is not just a conditioned response because the monkeys did not fear the rabbit or flower when shown the same fear responses from conspecifics; thus a genetic cause is also involved.
Quote:
Originally posted by Neo
Though one with a fear of snakes may have a better chance of survivng, it is not enough to change the genetic frequency of a population.
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Quite the opposite of what you say is true... An animal that has an innate fear of his predators will survive to reproduce and this behavioural characteristic
is enough to change the genetic frequency in a population. If an animal walks in front of a predator, it's going to get eaten, without a doubt. If I get into a car, the probability of me crashing and dying is next to nothing. That's where your comparison falls short.
Quote:
Originally posted by Neo
The selection pressure for snakes and fear of cars is nothing compared to the selection pressure for surfacing marine mammals
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On the contrary, these two selection pressures are quite similar (fear of predators and surfacing marine mammals). Both of them select strongly for life or death depending on whether or not the behaviour is exhibited, and whether or not these characteristics are exhibited would likely determine the animal's fate long before reproductive ability.
People still do fear cars, but the necessity for travel at high speed outweighs the very small chance of death - thus we can override this fear, as it doesn't remove enough of the pre-reproductive population to be a selective pressure. There is no benefit to not fearing your predators and it comes with a high chance of death, it's more than enough to change the genetic frequency in a population over millions of years.
You really only have two choices for innate behaviour; genetics or magic, my money's on the former.
Kind regards,
Ryan
P.S. These prenatal chemicals you speak of, even if these were the sole determination of behaviour (which simply is not true), why do you think these chemicals are being produced? Would it not be because mothers who produced these chemicals had offspring that exhibited behaviours that afforded them a selective advantage, and thus, the genetic frequency of these chemical-producing mothers would increase in the population.
"Nothing in Biology Makes Sense Except in the Light of Evolution"
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Theodosius Dobzhansky
edit: had an afterthought, nothing removed though...
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