Meaning of Sexual Reproduction
What is sexual reproduction:
Sexual reproduction is a process carried out by plants and animals, common in multicellular organisms, in order to procreate new living beings as offspring.
Two beings participate in sexual reproduction, one female and the other male, of which the new living being takes on genetic and physical characteristics. Therefore, it is considered a complex process.
Process of sexual reproduction
After sexual reproduction, a new living being is generated that inherits a series of characteristics from its parents, and so on. This is possible because the process of sexual reproduction begins with meiosis.
Meiosis is a specialized cell division process from which gametes are obtained. Gametes are the sex cells, that is, the ovules (female) and the sperm (male), which are provided by each of the parents and which contain half of the genetic information that the new living being will inherit.
The fusion of both gametes is known as fertilization, from which a cell called a zygote is created.
The zygote contains the genetic material of both gametes that, after genetic recombination, DNA, the homologous chromosome sequences are aligned and genetic information is shared. That is, the embryo begins to develop.
Then, two other cell divisions are carried out, from which four daughter cells are obtained that contain half the number of chromosomes of each original cell, and the same number of chromosomes that the parents have.
See also Chromosome.
In this way, the new living being obtains genetic information from both parents, so it will not be exactly the same as either of them, but it will be similar, even in the case of two or more offspring.That is, the new living being is unique.
This is also known as the cost of sexual reproduction, since the new living being only obtains 50% of the genes from its parents, from which it inherits what is considered both positive and negative, that is, a physical trait, a skill, a disease or syndrome, among others.
Types of sexual reproduction
Two types of sexual reproduction are distinguished according to the morphological and functional characteristics of the gametes.
Anisogamic sexual reproduction
Anisogamic sexual reproduction is the most frequent and used by multicellular organisms, that is, plants and animals.
In this type of sexual reproduction, gametes can be differentiated by their morphology and physiology. The male gamete or microgamete is small and mobile, it is called sperm. For its part, the female gamete or macrogamete is large and sedentary, it is called an ovum.
Therefore, anisogamous sexual reproduction occurs when both gametes unite and recombine their DNA, from which a new living being is created with characteristics of its parents.
Isogamic sexual reproduction
Isogamic sexual reproduction is that which occurs in some types of lower fungi, algae and protozoa. This type of reproduction is carried out by single-celled organisms.
Its main characteristics are that its gametes have the same morphology, that is, the same size and physiology.
For this reason, their gametes cannot be differentiated as female or male, however, to establish a difference the symbols (+) or (-) are used according to their behavior.
In this type of reproduction, after the union of cells, the genetic material is exchanged and the new living being is formed.