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We start the reflexion about how sex drives evolution from the maladaptive traits for survival that we can observe in certain animals. <br>A maladaptive trait for survival means that this trait is an inconvenience for the animal. It can be a physical trait (as the tail of the peacock that decreases its speed) or a trait that has to do with the behavior (for example the singing tùngara frogs that attract bats and bloodsucking flies). <br>The evident question that follows these observations is: How could such deficiencies be the result of natural selection? Charles Darwin was very worried about this question because in fact it could show a failure in his natural selection theory. | We start the reflexion about how sex drives evolution from the maladaptive traits for survival that we can observe in certain animals. <br>A maladaptive trait for survival means that this trait is an inconvenience for the animal. It can be a physical trait (as the tail of the peacock that decreases its speed) or a trait that has to do with the behavior (for example the singing tùngara frogs that attract bats and bloodsucking flies). <br>The evident question that follows these observations is: How could such deficiencies be the result of natural selection? Charles Darwin was very worried about this question because in fact it could show a failure in his natural selection theory. | ||
An observation will bring Darwin on the way of the answer: only males suffer from this type of elaborate trait. This is why we call them sexual dimorphism. We need to understand now how does it come sexual dimorphism | An observation will bring Darwin on the way of the answer: only males suffer from this type of elaborate trait. This is why we call them sexual dimorphism. We need to understand now how does it come sexual dimorphism to exist. The explanation of Darwin is that these traits aren't the result of a natural selection for survival, but a sexual selection in order to increase the chances of mating. In other words, the goal of these dimorphism is obviously not to increase the survival potential of an animal, but the reproductivity of this one. <br>There are two forms of sexual selection. The first one is the direct competition of the males, while the other is the female choosiness. | ||
Direct competition of the males | Direct competition of the males | ||
Version du 15 mars 2012 à 09:12
HOW SEX DRIVES EVOLUTION
Sexual Dimorphism
We start the reflexion about how sex drives evolution from the maladaptive traits for survival that we can observe in certain animals.
A maladaptive trait for survival means that this trait is an inconvenience for the animal. It can be a physical trait (as the tail of the peacock that decreases its speed) or a trait that has to do with the behavior (for example the singing tùngara frogs that attract bats and bloodsucking flies).
The evident question that follows these observations is: How could such deficiencies be the result of natural selection? Charles Darwin was very worried about this question because in fact it could show a failure in his natural selection theory.
An observation will bring Darwin on the way of the answer: only males suffer from this type of elaborate trait. This is why we call them sexual dimorphism. We need to understand now how does it come sexual dimorphism to exist. The explanation of Darwin is that these traits aren't the result of a natural selection for survival, but a sexual selection in order to increase the chances of mating. In other words, the goal of these dimorphism is obviously not to increase the survival potential of an animal, but the reproductivity of this one.
There are two forms of sexual selection. The first one is the direct competition of the males, while the other is the female choosiness.
Direct competition of the males The direct competition of the males is nothing more than a real struggle which has for prize reproduction.
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