To reproduce, males and females must cooperate, and this difficult task cannot be accomplished by one party alone, not only humans, but all mammals in nature are the reproductive mode of participation of both sexes.
This mode of reproduction is also called sexual reproduction, through which both sexes each provide a germ cell that is, a gamete, which is fused into a zygote, and then forms an embryo and develops into a mature individual, so that a new life is born.
But among all the creatures on earth, there is not only this way of reproduction, there is also a way of reproduction called asexual reproduction, which does not require the cooperation of the two sexes, and a mature individual can give birth to offspring just by copying himself.
Asexual reproduction can be non-split reproduction, budding reproduction, spore reproduction, and vegetative reproduction. Dividing reproduction occurs in some single-celled microorganisms, which can divide, from one to two, two to four, and so on.
Sprout reproduction generally appears in relatively inferior animals, such as polyps, hydras, etc., in their mother can grow a bud body, the bud body relies on the mother's nutrient growth, and when it matures, it will fall off the mother body and become a complete and independent individual.
Spore reproduction often occurs in some inferior plants, fungi, and algae, and they directly produce asexual spore cells, which can directly develop into individuals like the mother without insemination.
Nutritious reproduction this way we are more familiar, generally appear on the body of plants, we can use the tuber of the plant, such as the common potato, plant it in the field can grow a complete individual;
There are also some plant stems and leaves, directly inserted in nutrient-rich soil, or water, can grow into new individuals, such as domestic green roses, and the grafting of plant branches, all of which belong to asexual reproduction.
Even in some organisms in nature, there is not only the ability to reproduce asexually, but also the ability to reproduce sexually, such as some reptiles, birds, their eggs can hatch offspring without insemination;
There are also hydras that use budding reproduction, they can also undergo sexual reproduction, once flooded in our country water hyacinth, this aquatic plant also retains two ways of reproduction.
We know that life on Earth has evolved for billions of years, and that the creatures that remain today are survivors of natural evolution, because life has undergone several mass extinction events before that, and many unsuitable life has become extinct in the process of evolution.
Therefore, now the living things on the earth are the best, and the characteristics retained in all living things have their own reasons for existence, and the same is true for asexual reproduction, since nature has been preserved, it shows that it has the advantage of existence.
Yes, asexual reproduction does have great merits, and the history of existence is very old.
At the time of the emergence of life on Earth, the reproductive method of all living things at that time was asexual reproduction, and sexual reproduction was a breeding method that emerged after at least 2 billion years of evolution.
Asexual reproduction has irreplaceable advantages over sexual reproduction, for example, the speed of asexual reproduction is fast, simple and convenient, directly splitting and copying oneself can be, there is no need to find a partner, so there is no need to waste time and energy.
And if you have sexual reproduction, if you want to breed offspring, you must first find the other half, which is a very headache for young people now, obviously this is very troublesome, and when you find the other half, you still need to pay a certain price to obtain the consent of the other half and your request to reproduce offspring.
The process of obtaining consent is actually the courtship process of creatures in nature, in which the male has to please the female by dressing herself, building beautiful nests, and even singing and dancing.
For human beings, a man needs to have a handsome appearance, a tall man, but also need a house, a car, a deposit to please a woman, the whole process is cumbersome, pay too much time and energy.
And the way of sexual reproduction is slow to reproduce, no cell division comes quickly, take humans, the process of reproduction is two to one, and bacteria are one to two.
Finally, the biggest disadvantage of sexual reproduction is that the genes of the offspring contain only half of your genes, which is a great loss to the genetic genes, and the offspring of asexual reproduction have a full set of parental genes.
If asexual reproduction is so good, why can't humans reproduce offspring through asexual reproduction? That is to say, there is no distinction between the sexes, everyone can produce a reproductive cell, and this cell can develop a mature individual?
First of all, we need to understand one thing, although the organisms on the earth now retain asexual reproduction, but more than 90% of the organisms that reproduce sexually.
Therefore, to answer this question, we need to know why sexual reproduction is so troublesome, but it is chosen by most animals.
The reason is very simple, sexual reproduction is a disadvantage, but its positive effect on the earth's creatures is greater than all its shortcomings, resulting in the vast majority of organisms would rather trouble, would rather waste energy, prefer to inherit only half of their own genes, make such a huge sacrifice to choose sexual reproduction.
Because sexual reproduction can speed up the pace of evolution of organisms, the genetic diversity of the offspring produced is higher; sexual reproduction is the process of the two sets of genes of the parents disrupting the recombination, and this recombination is completely random, so that no matter how many offspring the two parents have, each offspring's genes are different.
That's why our siblings, and even twins, though similar in appearance, are not exactly the same, and that such offspring are more resilient to their natural environment due to their high genetic diversity.
And the probability of mutation in the process of genetic recombination is relatively high, genetic mutation is the root of biological evolution, with genetic mutation plus environmental selection, organisms will evolve rapidly.
That's why life on Earth has been around for more than two billion years, but it has always been simple single-celled life, until the advent of sexual reproduction, when there was a big explosion of life on Earth, not only in terms of species, but also in number.
And sexual reproduction also ensures that genes between individual beings can be communicated, and a good gene can spread rapidly throughout the population, making individuals in the entire population more excellent;
This is the same as the current global trade, you have good things, good technology can be exported to my side, I have good things can be exported to your side, so mutual cooperation and exchanges, it has promoted the rapid development and progress of both sides.
Asexual reproduction, although fast and convenient, but the offspring genes they are born are exactly the same as their own, the rate of gene mutation is low, resulting in slow biological evolution, and due to poor genetic diversity, it will make the entire population vulnerable to a bad environment.
Asexual reproduction and no genetic exchange, this is like a closed world without navigation before, there is no communication between countries, the degree of development is different, and it affects the development of the entire human society in general.
Therefore, sexual reproduction has the incomparable advantage of asexual reproduction, although it is more troublesome, but organisms are willing to give time and energy to sexual reproduction.
But asexual reproduction also has its advantages, so in some inferior organisms now still retain the form of asexual reproduction, and even some retain two forms of reproduction, when the natural environment is good, they can use the advantages of asexual reproduction to copy themselves in large quantities and rapidly, and when the environment is harsh, they can use sexual reproduction to fight against natural selection.
Humans, as the highest living creatures on the earth, of course choose sexual reproduction, in nature, asexual reproduction, including mammals, is a taboo, but with the development of human biotechnology, it has broken through the barrier.
Cloning techniques have perfectly enabled asexual reproduction of mammals.