Puberty - is a key component of post-embryonic development. Animals that have completed the embryonic development are not sexually mature, and there

Puberty in animals

Puberty — is a key component of post-embryonic development. Animals that have completed the embryonic development are not sexually mature, and therefore cannot reproduce. And many species at this stage of ontogenesis do not have sex organs at all. The ones, who already have such organs, still cannot use their functionality: it needs a certain period of development. Sexual maturity in males occurs at the beginning of spermatogenesis, and in females — at the first ovulation.

Sex determination

It turns out that in the early stages of post-embryonic development in many animals, even with the most sophisticated genetic methods, it is impossible to determine who is in front of you: the future female or male. It's all about the mechanism of sex determination. If the sex of the representatives of most groups of insects, birds and mammals is determined at the time of fertilization and depends only on the set of sex chromosomes in the zygote (one of the exceptions make Hymenoptera in which females come from fertilized eggs and males — from unfertilized), then in fish, amphibians and reptiles sex formation occurs in the period of post-embryonic development and is largely dependent on environmental conditions. It is known that a sharp rise in temperature of the water in which develop eggs of fish leads to the fact that only males may appear in the offspring. Moreover, the increase in the number of males in fish populations may be caused by any adverse environment change for development of larvae and young fish (salinity or pH of water, lack of food, and so on). In turtles, crocodiles, and snakes the sex of offspring is also dependent on the temperature of incubation of eggs. In some turtles low temperature leads to a male increase, high — females; males of other species appear at both low and at high temperatures, and females — at optimal moderate temperatures.

Puberty patterns

There are certain laws of puberty, which are valid only for specific groups of organisms. In particular, the following two patterns are found in mammals: Taken from http://worldofschool.org

  • females mature faster than males (food for thought: in fish, amphibians and reptiles, on the contrary, males mature earlier);
  • puberty occurs earlier than the body growth and maturation stop. As for the birth of healthy offspring the normal course of pregnancy is needed, as well as successful childbirth and stable feeding of milk, and thus only mature and strong organism can provide it, organisms have to avoid early pregnancies.

In plants, as well as in animals, puberty comes only after a sufficiently long period of growth. It is manifested in bloom — as in the flowers are “sexual organs” of plants: male (pollen sacks) and female (embryo sacs).

Questions:
  • Why physical maturation of human comes only after puberty?