Amphibians differ from fish?

Fish and amphibians in the system of biological classification are classes (or paraphyletic groups) included in a higher taxonomic group – type vertebrate (chordate) animals. Amphibians differ from fish biologically? Consider using recent scientific data.

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Origin

Today it is established that life on Earth originated in the ocean. The long evolution of simple organisms gradually led to the complexity of their biological organization in the end to the appearance of fishes, the vertebrates, whose life is fully connected to water bodies. When plants emerged from the ocean to the land, the animals followed the food sources: first, «vegan», and then the predators. Fish gradually mutate, transformed into creatures more adapted to life in shallow water and adjacent to the shore land areas – so there were amphibians.

Unlike amphibians from fish in the first place is that they have adapted to breathing out of the ocean. However, a close relationship with the pond made to develop a combined breathing: in addition to the lungs (as all the inhabitants of the land), in amphibians, there is an additional respiratory organs – the gills, and some even breathe through the skin (called «cutaneous respiration»). However, some species have only light – for example, frogs, which live in drier environments than most amphibians.

to table of contents ↑the Difference between amphibians and fish

Taxonomically (i.e. the classification system) of fish and amphibians are equivalent classes of vertebrates. As we’ve established, amphibians evolved from fish in the process of adapting to the changed conditions of life. However, they have quite a large number of the same features of buildings, way of life and reproduction. What they have in common?

First, is reproduction, which is carried out using spawning. Of course, this rule has exceptions. There are viviparous fish (e.g. some sharks) and viviparous amphibians (several species of toads and salamanders). However, reproduction through spawning is also found in fish, amphibians and much more. The number of live births is rather an exception to the rule.

Second, both are cold-blooded animals, therefore, are highly dependent on the ambient temperature: if fish environment more comfortable – because the water does not cool below zero (they always have the ability to go from «coming» of ice on the depth), then in amphibians is not so good. When the temperature becomes too low for normal metabolism, they hibernate. It is interesting that almost all amphibians can’t live in salt water, while fishes are everywhere. This is due to skin respiration: through the sensitive skin dissolved in sea water the salt «pulls» the body of the animal moisture, which has a lower salinity, and it dies from dehydration – such a paradox! The exception is the South American toad-yeah, which is in the process of evolution has adapted to life in salt water.

to content ↑Comparative table

To summarize, the difference between amphibians and fish. In addition to the above, you can add that ikromechuschie amphibians during the breeding process there is a stage where you have no fish. This, for example, we all know the tadpoles are intermediate between the egg and the adult frog. By the way, studying its development, biologists could observe a kind of mini-evolution of amphibians. Tadpoles are born with external gills and tail but without legs. Gradually they have pulmonary breathing, falls off the tail and grow legs, and soon we see a full-fledged frog.

Amphibians
Fish

Classification
Class included in type of chordate animals
Class included in type of chordate animals

Food
Herbivorous, omnivorous, predators
Herbivorous, omnivorous, predators

Reproduction
Spawning, live birth. From tailless amphibians there is a stage of development between egg and adult fish – tadpoles
Spawning, live birth

Lifestyle
Cold-blooded animals, are highly dependent on the ambient temperature. When poliitikaga critical hibernate. Can only live in fresh water (with few exceptions)
Cold-blooded animals. When the temperature of the water reduces the life activity, but hibernate not to fall. Different species of fish have adapted to survival in both salt and fresh water. There are species that can live in fresh water and at sea

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