Man and woman

In humans, as in the vast number of other living beings, there are two sexes, the connection which gives life to posterity. The role of the male and the female body and are similar and different.
The male body gives to the future being only their share of inheritance. In this respect he is equal with the female. The rest of the responsibility for the continuation of life-nature is laid on the female body. The egg - embryonic sexual cell in the female body is much larger than the sperm cell. It has not only an appropriate proportion of hereditary information, but also the necessary nutrients for the first days of the life of the embryo. After fertilization, the future of the living being is ripening in the bowels of the parent body.
By division, multiplication of germ cells in male and female organisms and the preparation of these cells to jump into the future they receive during the last dividing the only one, i.e. half, a set of chromosomes. The nature of detainees in its properties it is mixed. What does it mean?
All cells of the body, as already mentioned, have a double set of chromosomes from the father and the mother. When the last cell division, forming a reproductive cell, which will go on a meeting with the corresponding cell of the opposite sex, in each pair of chromosomes received from the father and the mother, the information is shared. After that, one of chromosomes, now how would a hybrid, is one of the formed two sex cells, the other is the same hybrid in another. These cells hybrid, but not identical. They are like a mirror: if, on any grounds, one of them has the gene father, another gene mother, and Vice versa. When one of these sex cells connected with the corresponding cell of the representative of the other sex, restore a double set of chromosomes that carry mosaic signs four individuals - both grandfathers and both grandparents. Of course, each of ancestors gets only a part of the features, but still a mixture produces a solid, natural selection is over what to work.
It is curious how different is the attitude of nature to the male and female organisms. In women during one menstrual-ovarian cycle (normally about 28 days) Matures, as a rule, only one egg. However, the mucous membrane of the uterus is prepared to accept the fertilized egg into his care, to become a kind of house to the fetus. If fertilization does not occur, the egg dies, mucous prepared to accept, reject, is menstruating, and it all starts again. Only in rare cases ripen simultaneously two egg. If fertilization develop and twins will be born, which may be a little similar to each other, even vary by sex. Such twins are called fraternal. If in the early stages of the development of one single fertilized egg after the first of a number of divisions will give the embryo, which will split into several independent parts which, of course, the same number of chromosomes, are developing so-called " identical twins. They are strikingly similar to each other. Again, it is in the female body the nature, as a rule, every time prepares only one egg. So what is this and is fertilized, then natural selection has no field of activity.
This is not the case in the male body. With each act of intercourse, is there ready to fertilize the egg or not (i.e., not yet or no longer exists), to the possibility of creating a new body rush huge amount of sperm up to 200 million In fact, it almost corresponds to the population of such countries as the Soviet Union or the United States. Right, then, was Walt Whitman, when, advertising live goods, shouted that the product that is the source of the public in the crowded". Saving on female embryonic material nature is very wasteful in relation to men. Here natural selection provides a wide field of activities. The selection process begins at the stage of sperm.
Providing all androgynous beings correspond two types of germ cells, nature was then take care of is that these cells could connect. The path here is very diverse.
In plants that do not have the ability to move, a very important role in the pollination pistils female flowers pollen from the stamen of male flowers play insects, in particular bees.
Animals, unlike plants, can move. Therefore, the mediator between the male and female gametes they do not need. In some cases, the embryo outside the body parents; for example, the female in the vast majority of fish spawning, male throws in a lot of eggs ROE. In other cases - and their vast majority - fertilization occurs in the genital tract of the female body. To do this nature had to solve two problems. First, when connecting, the male and female genitals anatomically and physiologically consistent with each other, were compatible; secondly - and more importantly, to male and female organisms were looking for connections. The solution of the latter problem, and was a strong sexual instinct, which exists in all androgynous animals. This instinct of nature to a high degree awarded and man. He received for these purposes feeling which we call love.
In love incorporate sincere sympathy and bodily desire. Only their unity and creates true love. Purely Platonic love, not aspiring to physical intimacy, and purely carnal love, no sympathy for the partner, is extremely defective ways of what nature has bestowed upon man.
Caring for the continuation of life, nature tried to make leading to it may be more attractive, a blissful. It is so compelling that people often divide it from the destination, what gave him the nature. It is impossible not to recall L. N. Tolstoy, who pointed out: "Sexual feeling in man and of all animals invested for the sacred cause of procreation, and deeply mistaken are those who believe that it is necessary to us for the fun of it".