- What is the reproduction of living beings?
- Reproduction types
- Animal reproduction
- Human reproduction
- Importance of reproduction
We explain what reproduction is and the types that exist. In addition, animal and human reproduction and why it is so important.
What is the reproduction of living beings?
Reproduction is known as one of the stages of the life cycle of living beings, together with birth, growth and death. It is a biological process by which organisms living beings create new organisms, more or less similar to themselves, thus perpetuating the species and guaranteeing its survival in time.
All the living beings are trained in one way or another for reproduction, although not all carry it out successfully or not all wish to do so, in the case of humanity. In fact, the vital stage of species maturation involves reaching the necessary development to allow eventual reproduction. This stage is also known as sexual maturity, at least in animal species.
Reproduction involves a set from processes more or less complex, which at a broader level allow the generation of new individuals, but which also occurs when the cells of the body of the same individual are regenerated, that is, they are replaced by younger cells. It is in this way that tissues are repaired, for example.
Reproduction types
The reproduction of living beings, broadly speaking, can be of two types: sexual and asexual, taking into account the genetic information of the newly formed individuals.
- Asexual reproduction. This is the most primitive form of reproduction, typical of the single-celled organisms. In it, a mature individual, who has reached the ideal conditions and is in an environment conducive to reproduction, initiates some type of bipartition, fission or replication that results in a new, young individual, but whose genetic information is identical to the one. from his progenitor. This process allows little genetic variability, other than through mutations. Some examples of asexual reproduction are gemmation, bipartition, fragmentation, sporulation, and parthenogenesis.
- Sexual reproduction. Much more complex from a genetic point of view, this mode of reproduction allows genetic exchange and a high rate of variety, since it consists of the creation of reproductive cells or gametes, each of which has half of the complete genetic load of a mature parent. Two of these gametes must meet and unite (fertilization) to give rise to a new individual, whose Genetic information It is its own and unique, different from that of its parents. This mode of reproduction is called sexual because the parents must be sexed organisms: male and female respectively, in order to reproduce.
Animal reproduction
Of oviparous animals, the fertilized female produces eggs and lays them in a nest.
The animals, for the most part, they reproduce sexually, which is why they are born with a sexual distinction: males and females. This implies that there must be a courtship process, in which the males generally dispute a female and the right to mate with her, and then a copulation, in which the victor or the chosen one can join the female and fertilize her. In some cases, this fertilization is internal, that is, it takes place within the female's body, where then new individuals develop and are expelled at the proper time; in other cases, fertilization is external, that is, it takes place in the environment, either under the care of the parents, or not.
In cases where fertilization is internal, the species can be classified according to method used for the offspring to emerge from the maternal body, as follows:
- Oviparous animals. The fertilized female produces eggs that are then deposited in a nest or some suitable place, and generally guarded by her parents. Within them there is a process of change and the offspring eventually emerge, either in an incomplete stage (as in the case of the amphibians or insects, in which the young must then pass through a metamorphosis to become adults) or in a full stage (as in the case of reptiles, whose young are identical to the adults but smaller).
- Viviparous animals. Those in which the fertilized female gives birth to her already developed young, ready to exist independently, although under the custody of their parents. In these cases, no eggs are produced, but the offspring (s) are gestated within the mother's body until they are ready and then they are given birth.
However, in some cases, animals can alternate between sexual and asexual reproduction, depending on the conditions. This is the case, for example, of starfish, which can regenerate a complete individual from a large enough fragment of tissue, such as a severed limb.
Another such asexual process is budding, in which one parent produces a lump or bud, from which a complete and identical individual is formed. It is a common reproduction mechanism between sponges and corals.
Human reproduction
Human reproduction is exclusively of a sexual nature (unless artificial techniques such as cloning), so it always involves two parents: female and male. When they reach sexual maturity, each one produces its gametes or reproductive cells: ovules in the female case and sperm in the male case, each one with half of the total genetic load of the individual.
As fertilization is internal, intercourse must take place, during which the male sexual organ (penis) is inserted into the female (vagina) until reaching the appropriate level of excitement for the ejaculation of male gametes into the vagina. and the uterus, where they will meet the ovum and fertilization will take place, thus giving rise to a zygote: a fertilized ovum that goes through a series of rapid and multiple cell divisions, initiating pregnancy.
The human pregnancy takes 9 months to gestate new individuals, which feed on the maternal body through the umbilical cord. Once this time has elapsed, labor occurs, in which the uterus begins a series of contractions that move the fetus out, through the birth canal, which has widened to allow its exit. Once outside, the umbilical cord must be cut and the newborn will begin its independent existence.
Importance of reproduction
Reproduction is an indispensable vital stage, since death inevitably overtakes all living beings. Organisms grow, age and their chances of continuing to exist become less, but it can always reproduce and bring into the world another or other new individuals that will prolong the species when it has already disappeared, and that in turn will reproduce when the time comes, in a life cycle that never ends.
In addition, playback allows innovation genetics, either by the random combinatorial of sexual reproduction, or by the possibility of mutations, which introduces new elements to the genetic information of the species, thus promoting the possibility of evolution and favorable adaptations, which may well save the entire species or, eventually, give rise to a new and better adapted one in its place. Anyway, the life always goes on.