Amphibians (class Amphibia), such as frogs Frogs are amphibians in the order Anura , formerly referred to as Salientia (Latin saltare, to jump). Most frogs are characterized by long hind legs, a short body, webbed digits (fingers or toes), protruding eyes and the absence of a tail. Frogs are widely known as exceptional jumpers, and many of the anatomical characteristics of frogs,, toads A toad can refer to a number of species of amphibians in the order Anura. A distinction is often made between frogs and toads by their appearance, prompted by the convergent adaptation among so-called "toads" to dry habitats. Many "toads" have leathery skin for better water retention, and brown coloration for camouflage. They, salamanders Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant species are grouped together as the Urodela. Most salamanders have four toes on their front, newts A newt is an amphibian of the Salamandridae family, although not all aquatic salamanders are considered newts. Newts are classified in the subfamily Pleurodelinae of the family Salamandridae, and are found in North America, Europe and Asia. Newts metamorphose through three distinct developmental life stages: aquatic larva, terrestrial juvenile ,, and caecilians The caecilians are an order (Gymnophiona or Apoda) of amphibians that superficially resemble earthworms or snakes. They mostly live hidden in the ground, which makes them the least explored order of amphibians, and widely unknown, are ectothermic Ectothermic, from the Greek ectos, "outside" and therme, "heat," refers to organisms that control body temperature through external means. As a result, organisms are dependent on environmental heat sources and have relatively low metabolic rates. For example, many reptiles regulate their body temperature by basking in the sun (or cold-blooded) animals that metamorphose from a juvenile water-breathing form, to an adult air-breathing form. Though amphibians typically have four limbs, the Caecilians The caecilians are an order (Gymnophiona or Apoda) of amphibians that superficially resemble earthworms or snakes. They mostly live hidden in the ground, which makes them the least explored order of amphibians, and widely unknown are notable for being limbless. Unlike other land animals (amniotes The amniotes are a group of tetrapod vertebrates that have a terrestrially adapted egg. They include mammals, birds and reptiles, as well as their fossil ancestors. Amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes. In humans, these membranes include the amniotic sac that), amphibians lay eggs in water. Amphibians are superficially similar to reptiles Reptiles, or members of the class Reptilia, are air-breathing, generally "cold-blooded" amniotes that generally have skin covered in scales or scutes. They are tetrapods (having or having descended from vertebrates with four limbs) and lay amniote eggs, whose embryos are surrounded by the amnion membrane. Modern reptiles inhabit every.
Amphibians are ecological indicators Ecological indicators are used to communicate information about ecosystems and the impact human activity has on ecosystems to groups such as the public or government policy makers. Ecosystems are complex and ecological indicators can help describe them in simpler terms that can be understood and used by non-scientists to make management decisions, and in recent decades there has been a dramatic decline in amphibian populations Dramatic declines in amphibian populations, including population crashes and mass localized extinctions, have been noted since the 1980s from locations all over the world. These declines are perceived as one of the most critical threats to global biodiversity, and several causes are believed to be involved, including disease, habitat destruction around the globe. Many species are now threatened or extinct.
Amphibians evolved in the Devonian Period The Devonian is a geologic period and system of the Paleozoic era spanning from 416 to 359.2 million years ago . It is named after Devon, England, where rocks from this period were first studied and were top predators in the Carboniferous The Carboniferous is a geologic period and system that extends from the end of the Devonian period, about 359.2 ± 2.5 Ma , to the beginning of the Permian period, about 299.0 ± 0.8 Ma (ICS, 2004) and Permian The Permian[note 1] is a geologic period and system characterized by widespread, diverse and maturing lifeforms which comes just after the Carboniferous and that extends from 299.0 ± 0.8 to 251.0 ± 0.4 Ma . It is the last period of the Paleozoic Era and famous for its ending epoch event, the largest mass extinction known to science. The Permian Periods, but many lineages were wiped out during the Permian-Triassic extinction The Permian–Triassic extinction event, informally known as the Great Dying, was an extinction event that occurred 251.4 million years ago, forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, with up to 96 percent of all marine species and 70 percent of terrestrial vertebrate. One group, the metoposaurs, remained important predators during the Triassic The Triassic is a geologic period and system that extends from about 251 to 199 Ma . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events. The extinction event that closed the Triassic period has recently been more, but as the world became drier during the Early Jurassic The Early Jurassic epoch (in chronostratigraphy corresponding to the Lower Jurassic series, originally the "Lias") is the earliest of three epochs of the Jurassic period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event (199.6 Ma (million years ago)) and ends at the start of the Middle Jurassic (175.6 Ma) they died out, leaving a handful of relict temnospondyls Temnospondyli are an important and extremely diverse taxon of small to giant primitive amphibians that flourished worldwide during the Carboniferous, Permian, and Triassic periods. A few stragglers continued into the Cretaceous. During their evolutionary history they adapted to a very wide range of habitats, including fresh-water aquatic, semi- like Koolasuchus Koolasuchus was a large Cretaceous amphibian that lived on the continent of Australia. It was a carnivore whose diet included turtles, clams and crayfish and the modern orders of Lissamphibia Extant amphibians fall into one of three orders—the Anura , the Caudata or Urodela (salamanders, including newts), and the Gymnophiona or Apoda (the limbless caecilians). Although the ancestry of each group is controversial, all share certain common characteristics, which indicates they evolved from a common ancestor and so form a clade. The.
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