As the psychotherapist in the well-known film said, "Sigmund Freud died at the age of 83 without ever knowing the answer to one question: What do women want?". Analyzing the sexual behavior of animals, popular presenter Julia Timonova suggested the following version.
Evolution is expressed in two opposite processes: natural selection and sexual selection. Natural selection is aimed at survival, sexual selection is for reproduction.
To determine the maximum sexual adaptation of any biological species, it is enough to look at the female of this species. All that the male differs from the female, is necessary for him not so much to survive, as to make an impression on the female. A vivid example in this case can be a pair of peacocks, mandarin ducks, pheasants.
Often, "decoration" of males contradicts even the instinct of self-preservation, because they can interfere with normal movement or negate the possibility of camouflage. That is, in this case the desire to multiply is stronger than the desire to survive.
In this case, we are talking about secondary sexual characteristics, according to which the female determines the reproductive value of the male. These signs should be clearly visible to her.
The more vivid such secondary sexual characteristics, the greater the chances of offspring. Accordingly, "love" for this attribute will be fixed from generation to generation in females' "mind", and the attribute itself - in males' appearance, becoming more and more vivid. Thus, females not only act as "breeders", but also transfer their "knowledge" to the next generations of females as well as males pass the external signs to the next generations of males.
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For example, as a result of sexual selection, a male of Argus (Argusianus argus) has grown such feathers that it can not fly and, as a consequence, his life usually is half the life of a female.
The basic rule that operates in the field of sexual selection was formulated by Bateman: who provides parental care, sets the rules, since it is regarded as a limited resource. It should be noted that the principle of Bateman acts the same way for both females and males. Accordingly, in situations where parents take on an approximately equal responsibility for caring for the offspring, we do not see a bright external sexual differentiation. For example, the male of seahorse has a very modest color.
In human society, sexual selection also takes place. It is interesting that in modern human society the contribution to the parental care of men and women is not always in favor of women. Thus, the requirements are often reciprocal. This holds the whole industry associated with beauty: beauty salons, plastic surgery etc.