What is the reproduction of living beings? Reproduction is known as one of the stages of the life cycle of living beings, along with birth, growth and death.
What is the reproduction of living beings? |
Reproduction is known as one of the stages of the life cycle of living beings, along with birth, growth and death.
It is a biological process through which living organisms create new organisms, more or less similar to themselves, thus perpetuating the species and guaranteeing its survival over time.
All 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 the maturation of the species implies reaching the necessary development to allow eventual reproduction. This stage is also known as sexual maturity, at least in animal species.
Reproduction implies a set of more or less complex processes, which at a broader level allow the generation of new individuals, but also occurs when the cells of the body of the same individual regenerate, that is, they are replaced by younger cells. It is in this way that the tissues are repaired, for example.
Types of reproduction
Asexual reproduction is typical of unicellular organisms.
The reproduction of living beings, in broad strokes, 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 unicellular 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 from his father. This process allows little genetic variability, except through mutations. Some examples of asexual reproduction are budding, 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 in the creation of reproductive cells or gametes, each of which has half the full genetic load from a mature parent. Two of these gametes must meet and unite (fertilization) to give rise to a new individual, whose genetic information is their own and unique, different from that of their 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 the oviparous animals, the fertilized female produces eggs and deposits them in a nest.
The animals, mostly reproduce sexually way, so born with sexual distinction: males and females. This implies that there must be a process of courtship, in which the males generally dispute a female and the right to mate with her, and then a copulation, in which the winner or the chosen one can join the female and fertilize her.
In some cases this fertilization is internal, that is, it takes place inside the female's body, where new individuals then develop and are expelled at the right time; in other cases, fertilization is external, that is, it takes place in the environment, whether under the care of the parents, or not.
In cases where fertilization is internal, the species can be classified according to the 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 their parents. Within them there is a process of change and the offspring eventually emerge, either in an incomplete stage (as in the case of amphibians or insects, in which the offspring must then go through a metamorphosis to become adults) or in a stage complete (as in the case of reptiles, whose offspring are identical to adults but smaller).
- Viviparous animals. Those in which the fertilized female gives birth to her already developed offspring, ready to exist independently, although in the custody of their parents. In these cases, eggs are not produced, but the offspring or babies are born inside the mother's body until they are ready and then they are calved.
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 sufficiently large fragment of tissue, such as a severed limb.
Another similar asexual process is the budding, in which a parent produces a lump or yolk , from which a complete and identical individual is formed. It is a usual reproduction mechanism between sponges and corals.
Human reproduction
Human reproduction is exclusively of the sexual type (unless artificial techniques such as cloning are considered within “reproduction”), 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 with half the total genetic load of the individual.
As fertilization is internal, intercourse should occur, during which the male sexual organ (penis) is introduced into the female (vagina) until the level of excitation is reached for ejaculation of male gametes inside the vagina and the uterus, where they will meet the ovule and fertilization will occur, thus giving rise to a zygote: a fertilized egg that goes through a series of rapid and multiple cell divisions, beginning pregnancy.
Human pregnancy takes 9 months to gestate new individuals, which feed on the maternal body through the umbilical cord. Once this time has elapsed, childbirth occurs, in which the uterus begins a series of contractions that move the fetus outward, through the birth canal, which has widened to allow its exit. Once outside, the umbilical cord should be cut and the newborn will begin its independent existence.
Importance of reproduction
Reproduction is an indispensable vital stage, given that all living beings inevitably survive death.
The organisms grow, age and their chances of continuing to exist become smaller, but they can always reproduce and bring to the world another or other new individuals that will prolong the species when it has already disappeared, and which in turn will reproduce when the time comes, in A life cycle that never ends.
In addition, reproduction allows genetic innovation, either by the random combinatorial of sexual reproduction, or through 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 instead. In any case, life always continue
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