Amphibian reproduction

Author: Peter Berry
Date Of Creation: 16 February 2021
Update Date: 21 November 2024
Anonim
Lecture 6: Amphibian Reproduction
Video: Lecture 6: Amphibian Reproduction

Content

One of the great aspects of evolution was the conquest of the terrestrial environment by animals. The passage from water to land was a unique event, without a doubt, that changed the development of life on the planet. This wonderful transition process left some animals with an intermediate body structure between water and land, which are fully adapted to terrestrial environments, but generally remain attached to water, mainly for their reproduction.

What was said above refers to amphibians, whose name precisely comes from their double life, aquatic and terrestrial, the only vertebrates that are currently capable of metamorphosis. Amphibians belong to the tetrapod group, are amniotes, that is, without amniotic sac, albeit with certain exceptions, and most breathe through gills in the larval stage and in a pulmonary manner after metamorphosis.


In this article by PeritoAnimal, we want you to know how these animals reproduce, since it is one of the aspects that keep them linked to the aqueous environment. Read on and learn about the amphibians reproduction.

Amphibian classification

At present, amphibians are grouped into Lissamphibia (lissamphibians) and this group, in turn, branches or divides into three:

  • gymnophiona: they are commonly known as caecilians and are characterized by being legless. Furthermore, they are the ones with the fewest species.
  • Tail (Tail): correspond to salamanders and newts.
  • Anura: corresponds to frogs and toads. However, it is noteworthy that these two terms do not have taxonomic validity, but are used to distinguish small animals with smooth and moist skin, from those with drier and more wrinkled skin.

For more information, we encourage you to read this other article on Amphibian Characteristics.


Type of reproduction of amphibians

All these animals have a type of sexual reproduction, however, they express a wide variety of reproductive strategies. On the other hand, although it is common to believe that all amphibians are oviparous, it is necessary to clarify this matter.

Are amphibians oviparous?

Cecilias have an internal fertilization, but they can be oviparous or viviparous. Salamanders, on the other hand, can have internal or external fertilization, and as for the embryonic development modality, they exhibit several ways depending on the species: some lay fertilized eggs that develop outside (oviparity), others keep the eggs inside the female's body, expelling when the larvae are formed (ovoviviparity) and in other cases they keep the larvae internally until they metamorphose, expelling the fully formed individuals (viviparity).


As for anurans, they are usually oviparous and with external fertilization, but there are also some species with internal fertilization and, additionally, cases of viviparity have been identified.

How is the reproduction process of amphibians?

We already know that amphibians express multiple reproductive forms, but let's know in more detail how amphibians reproduce.

Reproduction of caecilians

Male caecilians have a copulatory organ with which the females fertilize. Some species lay their eggs in wet areas or near water and the females take care of them. There are other cases where they are viviparous and keep the larvae all the time in their oviduct, on which they feed.

Reproduction of tails

As for the caudates, a reduced number of species express external fertilization, while most have internal fertilization. The male, after performing a courtship, leaves the sperm usually on some leaf or branch to be later taken by the female. Soon, the eggs will be fertilized inside the mother-to-be's body.

On the other hand, some species of salamanders lead an entirely aquatic life and the laying of their eggs takes place in this medium, placing them in mass or groups, and larvae emerge with gills and a fin-shaped tail. But other salamanders lead an adult terrestrial life after metamorphosis. The latter lay their eggs on the ground in the form of small bunches, usually under moist, soft soil or damp trunks.

Several species tend to keep their eggs for protection and, in these cases, the larval development it occurs totally inside the egg, therefore, individuals with a shape similar to that of adults hatch from it. Cases were also identified in which the female keeps the larvae during their complete development until the adult form, at which point they are expelled.

frog reproduction

The male frogs, as we mentioned before, usually fertilize the eggs abroad, although few species do it internally. They attract the females through the emission of their songs, and when she is ready, he approaches and the attachment occurs, which is the positioning of the male over the female, so that as she releases the eggs, the male will. fertilizing.

The ovoposition of these animals can occur in different ways: in some cases it is aquatic, which includes different ways of laying eggs, in others it occurs in foam nests over water and it can also be done in an arboreal or terrestrial way. There are also some cases in which larval development takes place on the mother's skin.

Why Water Is Necessary for Amphibian Breeding

Unlike reptiles and birds, amphibians produce eggs without the shell or hard covering that involves the embryo of these animals. This, in addition to allowing gas exchange with the outside because it is porous, offers high protection against a dry environment or a certain level of high temperature.

Amphibian embryonic development

Because of this, amphibian embryonic development must occur in a aqueous medium or in wet environments so that, in this way, the eggs are protected, mainly against the loss of moisture, which would be fatal to the embryo. But, as we already know, there are species of amphibians that don't put them in the water.

In these chaos, some strategies are to do it in damp places, underground or covered by vegetation. They can also produce quantities of eggs involved in a gelatinous mass, which gives them ideal conditions for development. Even species of anurans that carry water to the terrestrial place where they develop their eggs have been identified.

These vertebrates are a clear example that life seeks evolutionary mechanisms necessary to adapt and develop on Earth, which can be clearly seen in their varied ways of reproduction, which constitutes a wide range of strategies for the perpetuation of the group. .

Amphibian conservation status

Many amphibian species are cataloged in some degree of extinction danger, mainly due to their dependence on water bodies and how susceptible they can be to the massive changes that are currently taking place in rivers, lakes and wetlands in general.

In this sense, strong actions are needed to stop the deterioration to which these ecosystems are submitted, in order to conserve amphibians and the rest of the species that depend on these habitats.

If you want to read more articles similar to Amphibian reproduction, we recommend that you enter our Curiosities section of the animal world.