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Frogs are valued as food by humans and also have many cultural roles in literature, symbolism and religion. They are also seen as environmental bellwethers, with declines in frog populations often viewed as early warning signs of environmental damage. Frog populations have declined significantly since the 1950s.
Adult frogs do not have tails and caecilians have only very short ones. [68] Didactic model of an amphibian heart. Salamanders use their tails in defence and some are prepared to jettison them to save their lives in a process known as autotomy. Certain species in the Plethodontidae have a weak zone at the base of the tail and use this strategy ...
Amniotes are distinguished from the other living tetrapod clade — the non-amniote lissamphibians (frogs/toads, salamanders, newts and caecilians) — by the development of three extraembryonic membranes (amnion for embryonic protection, chorion for gas exchange, and allantois for metabolic waste disposal or storage), thicker and keratinized ...
Ossea Batsch, 1788[2] Vertebrates (/ ˈvɜːrtəbrɪts, - ˌbreɪts /) [3] are deuterostomal animals with bony or cartilaginous axial endoskeleton — known as the vertebral column, spine or backbone — around and along the spinal cord, including all fish, amphibians, reptiles, birds and mammals.
Pig frogs (Lithobates grylio) are a species of frog that belong to the class Amphibia, the order Anura, the family Ranidae, and the genus Lithobates. They are part of the phylum Chordata, which includes animals with a notochord and a hollow nerve cord. Pig frogs are vertebrates, meaning they have a backbone, and they are tetrapods, meaning they ...
Each is a member of one of three monophylitic clades. All tunicate larvae have the standard chordate features, including long, tadpole-like tails. Their larva also have rudimentary brains, light sensors and tilt sensors. [28] The smallest of the three groups of tunicates is the Appendicularia. They retain tadpole-like shapes and active swimming ...
Tetrapod. A tetrapod (/ ˈtɛtrəˌpɒd /; [5] from Ancient Greek τετρα- (tetra-) 'four' and πούς (poús) 'foot') is any four- limbed vertebrate animal of the superclass Tetrapoda (/ tɛˈtræpədə /). [6] Tetrapods include all extant and extinct amphibians and amniotes, with the latter in turn evolving into two major clades, the ...
It is a paraphyletic grouping including all animals excluding the chordate subphylum Vertebrata, i.e. vertebrates. Well-known phyla of invertebrates include arthropods, mollusks, annelids, echinoderms, flatworms, cnidarians, and sponges. The majority of animal species are invertebrates; one estimate puts the figure at 97%. [1]