All living beings on the planet must reproduce to perpetuate the species Despite this, not all of them succeed or, not necessarily, all members of a species reproduce. For example, animals that live in eusocieties are assigned a function within the group and only one or several individuals reproduce. In contrast, solitary animals will seek and fight for their right to reproduce and maintain their own genes.
Another large group of animals will carry out another reproductive strategy, in which they will not need the presence of the opposite sex to reproduce. We will talk about all of them in this article on our site. Do you want to know more about reproduction in animals? Continue reading!
What is reproduction in animals?
Reproduction in animals is a complex process of hormonal changes that cause physical and behavioral transformations in individuals to achieve a single goal: to create offspring.
The first change that must occur is sexual maturation of the animals. This fact occurs at a certain time in the life of each individual depending on its species. It all begins with the establishment of the sexual organs and the formation of gametes, which is called spermatogenesis in males and oogenesis in females. After this episode, part of the animals' lives is centered around the search for a mate in order to establish a bond that will lead them to reproduce.
However, there are animals that, despite having these organs, at certain times under specific conditions, do not use them. This is known as asexual reproduction in animals.
Types of animal reproduction
In nature there are several types of reproduction in animals. Each of them has defined characteristics that make them very different from each other. Broadly speaking, we could say that types of animal reproduction are:
- Sexual reproduction in animals
- Asexual reproduction in animals
- Alternate reproduction in animals
Next, we will talk and give examples of each of them.
Sexual reproduction in animals
Sexual reproduction in animals is characterized by two individuals being involved, a female and a maleThe female will produce ovules formed by oogenesis in her ovaries. On the other hand, the male creates sperm in his testicles, which are generally characterized by being small and very mobile. These sperm have the function of fertilizing the ovum and forming a zygote that, little by little, will develop until creating a complete individual.
Fertilization can take place inside or outside the female body. This is known as internal or external fertilization, depending on the species.
Internal fertilization in animals
During internal fertilization, the sperm travel through the female's reproductive system in search of the egg. The female will then be able to develop offspring inside, as occurs with viviparous animals, or outsideIf embryonic development takes place outside the female body, we would speak of oviparous animals, which lay eggs.
External fertilization in animals
On the contrary, animals with external fertilization, release their gametes into the environment (normally into the water), both eggs and sperm, fertilization occurring outside the body.
The most important characteristic of this type of reproduction is that the resulting individuals carry in their genome genetic material from both parents By Therefore, sexual reproduction increases the probability of long-term survival of a species thanks to the genetic variability it produces.
Asexual reproduction in animals
Asexual reproduction in animals is characterized by the absence of another individual of the opposite sex. Therefore, the offspring is identical to the reproducing individual.
In addition, asexual reproduction does not necessarily involve germ cells, that is, eggs and sperm; in most cases they are somatic cells with dividing capacity. Somatic cells are the normal cells of the body.
Types of asexual reproduction in animals
Next, we will see that there are several types of asexual reproduction in animals:
- Gemation or gemulation: it is the typical asexual reproduction of sea sponges. A specific type of cell accumulates food particles and, in the end, separates and creates a gemmule that gives rise to a new individual.
- Budding: In hydras, a specific type of cnidarian, asexual reproduction occurs by budding. On the surface of the animal, a specific group of cells begins to grow, forming a new individual that can separate or remain united.
- Fragmentation: is one of the types of reproduction carried out by animals such as starfish or planaria. Its body can be segmented into several pieces and each one gives a new individual.
- Parthenogenesis: In this type of asexual reproduction, a germ cell, the ovule, is involved. This, even if it is not fertilized, can develop and create a female individual identical to its mother.
- Gynogenesis: This is a rare case of asexual reproduction, occurring only in certain amphibians and bony fishes. The male donates his sperm, but this is only used as a stimulus for the development of the egg; it doesn't really contribute its genetic material.
Animals with asexual reproduction
Some of the animals with asexual reproduction that we can find are:
- Hydra
- Wasps
- Sea stars
- Sea Anemones
- Sea urchins
- Sea Cucumbers
- Sea sponges
- Amoebas
- Salamanders
For more information, you can consult this other article on Asexual reproduction in animals.
Alternate reproduction in animals
In animals, although it is not very common, we can find alternating reproduction. During this reproductive strategy, sexual reproduction is interspersed with asexual, although not necessarily.
This type of reproduction is very common in the plant world. In animals it is rare, but we can observe it in certain eusocieties, such as ants and bees, that is, in invertebrate animals.
The strategy of alternate reproduction in animals will depend on each species. For this reason, we advise you to read the following article on Alternate reproduction in animals for more detailed information.
