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Several groups of tetrapods have undergone secondary aquatic adaptation, an evolutionary transition from being purely terrestrial to living at least part of the time in water. These animals are called "secondarily aquatic" because although their ancestors lived on land for hundreds of millions of years, they all originally descended from ...
The origins and evolutionary relationships between the three main groups of amphibians (apodans, urodeles and anurans) is a matter of debate.A 2005 molecular phylogeny, based on rDNA analysis, suggested that the first divergence between these three groups took place soon after they had branched from the lobe-finned fish in the Devonian (around 360 million years ago), and before the breakup of ...
The majority of amphibians — except the order Gymnophiona , which are mainly terrestrial burrowers — have a fully aquatic larval form known as tadpoles, but those from the order Anura (frogs and toads) and some of the order Urodela (salamanders) will metamorphosize into lung-bearing and sometimes skin-breathing terrestrial adults, and most ...
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
It is found in all major animal groups, including birds, mammals, fish, reptiles, amphibians, insects, and crustaceans. The cause of migration may be local climate, local availability of food, the season of the year or for mating.
The list below largely follows Darrel Frost's Amphibian Species of the World (ASW), Version 5.5 (31 January 2011). Another classification, which largely follows Frost, but deviates from it in part is the one of AmphibiaWeb , which is run by the California Academy of Sciences and several of universities.
The smallest amphibian (and vertebrate) in the world is a frog from New Guinea (Paedophryne amauensis) with a length of just 7.7 mm (0.30 in). The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander ( Andrias sligoi ), but this is dwarfed by prehistoric temnospondyls such as Mastodonsaurus which could reach up to 6 m ...
At least nine groups of vertebrate OR genes have been identified (α,β,γ,δ,ε,ζ,η, and θ), each of which derived from ancestral genes in the most common ancestor of tetrapods and fish. [5] Specifically, vertebrate OR genes convey an evolutionary pattern of three separate lineages: fish, amphibians, and mammals. [10]