Os anfíbios compõem o grupo mais primitivo de vertebrados. Seu nome significa “vida dupla” (anfi= ambos e bios= vida) e eles são animais ectotérmicos, ou seja, dependem de fontes externas de calor para controlar seu equilíbrio interno. Além disso, são amniotas, como os peixes. Isso significa que seus embriões não são envolvidos por uma membrana: o âmnio.
On the other hand, the evolution of amphibians and their passage from water to land occurred for millions of years. Their ancestors lived about 350 million years ago, at the end of the Devonian, and their bodies were robust, with wide, flattened legs and many fingers. It was the Acanthostega and Icthyostega, who were the ancestors of all the trapables we know today. Amphibians have a global distribution, although they are not present in desert regions, polar and Antarctic areas and some oceanic islands. Continue reading this peritoAnimal article and you will understand all the characteristics of amphibians, their peculiarities and their lifestyles.
- Amphibians are vertebrate tethrhipod animals.
- That is.
- They have bones and four limbs.
- It is a very special group of animals because they undergo a metamorphosis that allows them to move from the larval stage to the adult stage.
- Which also makes them.
- Throughout their lives.
- Have different breathing mechanisms.
There are three types of amphibians, classified as follows
Among the characteristics of amphibians are the following elements:
Amphibians have certain characteristics in their way of life. Unlike other titracpods, they undergo a process called metamorphosis, during which the larva, tadpole, transforms into an adult and goes from gill to pulmonary breathing. During this process there are countless structural and physiological changes, through which the organism prepares to move from aquatic to terrestrial life.
Amphibian eggs are deposited in water; therefore, when the larva hatches, it has gills to breathe, a tail and a circular mouth to eat. After a while in the water, she will be ready for metamorphosis, in which she will undergo dramatic changes ranging from the disappearance of the tail and gills, as in some salamanders (Urodelos), to profound changes in organic systems, as happens in frogs. (Ranas). The following also occurs:
However, some species of salamanders may not need metamorphosis and still reach adult status with larvae characteristics, such as the presence of gills, which make them look like a small adult. This process is called neothenia.
All modern amphibians, i.e. Urodelos or Caudata (salamanders), Anoures (ranas) and Gimnofiona (céciles), are jointly referred to as Lissanphibia, and this name derives from the fact that these animals do not have scales on the skin, so they are “naked”. . They have no other skin coating like other vertebrates, whether by hairs, feathers or scales, except for ceciles, whose skin is covered by a type of “skin dandruff”.
On the other hand, their skin is very thin, which facilitates their skin breathing, is permeable and has a rich vascularity, pigments and glands (in some cases toxic) that allow them to protect themselves from the abrasion of the environment and other individuals. , acting as your first line of defense.
Many species, such as dendrobatids (poisonous frogs), have very bright colors that allow them to give a “warning” to their predators, as they are very impressive, but this coloration is almost always associated with poison glands. This in nature is called animal aposmatism, which is essentially a warning coloration.
This group of animals has a great variation in terms of skeleton compared to other vertebrates. During their evolution, many bones of the anterior limbs have been lost and modified, but their size, on the other hand, is much more developed.
The front legs have four toes and five hind legs, and are elongated for jumping or swimming, with the exception of Cecilia, who has lost her hind legs due to her lifestyle. On the other hand, depending on the species, the hind legs can be adapted for jumping and swimming, but also for walking.
Amphibian mouths are characterized by the following characteristics
The amphibian tongue facilitates feeding and some species manage to project it outwards to capture prey.
Answering the question of what amphibians eat is a bit complicated, as the diet of amphibians varies with age and can feed on aquatic vegetation in the larval state and small invertebrates in adulthood, such as:
There are also predatory species that can feed on small vertebrates, such as fish and mammals. An example of this is the bull frog (found in the group of frogs), which are opportunistic hunters and can often even drown when they try to swallow too large a prey.
Amphibians have gills (in larval phase) and skin breathing, thanks to their fine, permeable skin, allowing them to exchange gases. However, adults also have pulmonary breathing and, in most species, combine the two modes of breathing throughout life.
On the other hand, some species of salamanders completely lack lung breathing, so they only use gas exchanges through the skin, which is usually bent, thus increasing the area of exchange.
Amphibians have separate sexes, i.e. they are dioetic and, in some cases, there is sexual dimorphism, which means that men and women are distinguishable. Fertilization is mainly external in anuras and internal in urodeles and gymnoids. They are oviparous animals and their eggs are deposited in water or in wet soils to avoid drought, but in the case of salamanders, the male leaves a packet of sperm in the substrate, called spermatophorus, to be collected later by the female.
Amphibian eggs are placed inside frothy masses produced by the parents and, in turn, can be protected by a gelatinous membrane that also protects them from pathogens and predators. Many species receive parental care, although it is rare, and this care is limited to transporting eggs in the mouth or tadpoles in the back, and changing them if there is a predator nearby.
In addition, they have sewer, like reptiles and birds, and it is by this channel that reproduction and excretion occurs.
In addition to the characteristics mentioned above, amphibians are also differentiated by the following:
If you would like to read articles similar to Amphibian Characteristics, we recommend that you visit our Curiosities section of the animal world.