WHAT IS CROSS-FERTILIZATION? - BIOLOGY - 2025

The outcrossing or outcrossing explains fertilization occurs when in the same plant or animal species, the female reproductive cells are in an individual and the male reproductive cells in another individual.

Both cells are necessary to produce a new individual of the species, therefore, it is necessary that there is a union of the male and female gametes, although the reproductive organs are separated.

The concept is opposed to autogamy, which is the term that describes self-fertilization, when an individual reproduces without the need to obtain genetic material from another individual.

In this case, the result is a uniparental fertilization. For example, when a flower is fertilized with its own pollen.

Characteristics of cross-fertilization

Advantage

With cross-fertilization, genetic material from two individuals, mother and father, is recombined to maintain greater variety in natural selection and the ability to adapt to changes in the environment.

In this way it is possible to produce an offspring that is not subject to diseases or genetic disadvantages. The more genes an individual has, the more protected he is against the extinction of his species.

In other words, the result of cross-fertilization is stronger, healthier individuals with a lower propensity for birth defects and other conditions.

In aquatic animals

Cross-fertilization occurs in most animal species. In aquatic animals it happens that both the male and the female release their sex cells into the water and fertilize themselves outside their bodies.

That is, the sperm joins the egg in the external environment. Although internal fertilization also occurs in some fish and other aquatic species.

In terrestrial animals

In the terrestrial environment, fertilization occurs within the individual, that is, it is internal. Sperm, a set of male sex cells, is placed inside the body of the female individual.

Individuals that are born from this union of gametes from different parents are called biparentals, for example: cockroaches, frogs, reptiles, mammals, birds.

In plants

In plants, cross-fertilization means that one plant is fertilized with pollen from a different plant.

This happens, as it happens with animals, because they have the female and male organs in separate individuals.

In the most basic plants such as mosses and liverworts, sperm is released from one individual through a film of moisture, towards the egg-receiving structure of another individual.

In more advanced plants, cross-fertilization is achieved through pollination.

This occurs when the pollen grains, which make the sperm bloom, are transferred to the cones or flowers of another plant that has receptivity for eggs in those cones or flowers.

Pollination can occur by wind, as in conifers. It can also occur through symbiotic relationships with animals, such as bees, certain birds, and also bats, which carry pollen from one plant to another while feeding on the nectar.

References

1. Editors. (2014). Fertilization. 09/30/2017, from Biology Dictionary Website: biologydictionary.net
2. Editorial. (2012). Definition. 09/29/2017, from Cambridge Dictionary Website: dictionary.cambridge.org
3. Editor. (2017). Allogamy. 10/03/2017, from Biology on line Website: www.biology-online.org
4. Editor. (2012). Cross fertilization. 09/29/2017, from ACADEMIC Website: encyclopedia_universal.esacademic.com
5. cross-fertilization. (nd). In Collins English Dictionary. Retrieved September 30, 2017, from www.collinsdictionary.com