The word “Amphibian” is derived from the Ancient Greek term ἀμφίβιος (amphíbios), which means “both kinds of life”, ἀμφί meaning “of both kinds” and βιος meaning “life”. The term was initially used as a general adjective for animals that could live on land or in water, including seals and otters. Traditionally, the class Amphibia in its widest sense was divided into three subclasses, two of which are extinct. All modern amphibians include frogs, toads, salamanders, newts and caecilians.
Frogs and Toads: Order Anura….Jurassic to present–5,602 current species in 48 families
Salamanders/Newts: Order Caudata or Urodela….Jurassic to present –571 current species in 10 families
Caecilians: —-Caecilians are a legless, tailless tropical amphibian.They make up the order Gymnophiona, one of the three orders from the class Amphibia. Order Gymnophiona or Apoda….Jurassic to present—190 current species in 10 families.
The numbers of species shown above is approximately 7,000. Nearly 90% are frogs.
This information comes from:
http://en.wikipedia.org/wiki/Amphibian
Frogs:
Most people are surprised to hear that all Toads are actually Frogs! But frogs of any kind are not toads. Generally speaking, when we think of frogs, the information is referring to “True Frogs”….members of the family Ranidae which contains more than 400 species. These frogs have the characteristics of: two bulging eyes; strong, long, webbed hind feet that are adapted for leaping and swimming; smooth or slimy skin (generally, frogs tend to like moister environments) and frogs tend to lay eggs in clusters. Frogs from this family can be found on every continent except Antarctica. They are referred to as the “true frogs” because of their generalized body form and life history. Then there is the so-called generic frog: Members of this family include the bullfrog, common frog, green frog, leopard frog, marsh frog, pickerel frog, and wood frog.
Toads:
The term toads tends to refer to “True Toads”….members of the family Bufonidae, containing more than 300 species. These types of frogs are characterized by: stubby bodies with short hind legs (for walking instead of hopping) warty and dry skin (usually preferring dryer climates) paratoid (or poison) glands behind the eyes. The chest cartilage of toads is different also. Toads tend to lay eggs in long chains. There are some toads (genera Nectophrynoides), however, that are the only types of *anurans* to bear live young! True Toads can be found worldwide except in Australasia, polar regions, Madagascar, and Polynesia, though Bufo marinus has been artificially introduced into Australia and some South Pacific islands. Besides Bufo, the family includes 25 genera, all of which, like the frogs, are anura! The physical distinctions, however, can easily get blurred because sometimes the features appear mixed or less obvious, and certain species even legitimately fall into both categories. It is not uncommon, for example, to find a warty skinned frog that isn’t a toad, or even a slimy toad! Even the more invisible stuff like cartilage structure has been found to sometimes fit both categories!
*anuran: [From New Latin Anra, order of frogs and toads : a- + Greek our, tail; see ors- in Indo-European roots.]*
Salamander:
A common name for the order of Caudata of which 8 are found in North America.
Although lizard-like in external appearance, you can tell the difference between salamanders (Amphibians) and lizards (Reptiles) because salamanders do not have scales or claws. Salamanders can be differentiated from other amphibians (frogs and caecilians) by the presence of a tail in all larvae, juveniles, and adults, and by the fact that their forelimbs and hindlimbs typically are of about the same size (sirens lack hindlimbs) and are set at right angles to the body (Larson et al. 2006.)
Salamanders not only provide benefit to their ecosystem through their role in food webs, but also provide benefit to humans beings. They help to control pest species, such as mosquitoes, are model organisms in medical and genetic research, and provide aesthetic benefits in art, literature, and simply through increasing the human enjoyment of nature.
Salamanders generally have a biphasic life cycle, typified by an aquatic larval stage with external gills and a terrestrial adult form that utilizes lungs or breathes through moist skin (Larson et al. 2006). However, some species are aquatic throughout life, not undergoing metamorphosis to a terrestrial, air-breathing adult, and some are terrestrial throughout life, hatching on land and lacking the larval aquatic stage. Furthermore, some aquatic forms lack gills and use lungs.
Newt:
A common name which applies to certain members of the salamander family that are also in the order of Caudata. Newts, however, are aquatic salamanders, which have no hind limbs. Salamanders consist of 350 species out of the 4000 or so known species of amphibians. So, Newts are Salamanders but Salamanders are not Newts. Just like a Toad is a Frog but a Frog is not a Toad.
Newts are also known as an eft. They too are an aquatic amphibian of the family Salamandridae, 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 (called an eft[1]), and adult. Adult newts have lizard-like bodies and may be either fully aquatic, living permanently in the water, or semi-aquatic, living terrestrially but returning to the water each year to breed.
This information about frogs/toads is from: http://allaboutfrogs.org/weird/general/frogtoad.html
http://allaboutfrogs.org/weird/weird.html
http://en.wikipedia.org/wiki/Newt*anuran definition is from:http://www.thefreedictionary.com/anuran
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Amphibians are among the first species to be affected by environmental stressors, so when they show declines in the wild, it is a warning to other species, including humans. Their population declines and extinctions signal that changes are occurring in the environment that will also negatively impact humans. Amphibians are dying in alarming numbers. About 122 species are believed to have become extinct since 1980. About half of the world’s 6,000 species could become extinct within our lifetime with at least 500 species facing imminent extinction. This rate of extinction is unprecedented since the demise of the dinosaurs. Destruction of habitat, invasive species (plant and animal), pollution, global warming and other human influences threaten many species throughout the animal and plant kingdom.
In addition to these challenges, amphibians are being attacked by a lethal disease that has caused unprecedented and unexpected losses, called chytrid fungus. Chytrid quickly and quietly destroys entire species when introduced to new populations in the wild. Chytrid fungus has now been identified in association with amphibian die-offs on every amphibian-inhabited continent. This disease has decimated or wiped out species that had not been considered critically endangered. It happens so quickly that species disappear before anyone realizes they are in trouble. Amphibian chytrid is a disease that infects the skin of amphibians, a vital organ through which many drink and breathe. It was discovered a decade ago; dozens of frog species have already vanished because of it. In environments where it thrives, the fungus can kill 80 percent of the native amphibians within months. Currently, it is unstoppable and untreatable in the wild, even in ‘protected’ areas. Amphibian chytrid is believed to have originated in Africa. The export of African clawed frogs (likely resistant carriers of the fungus) around the world for human pregnancy testing and lab studies spread this disease worldwide. Recently, the food and pet trades may have contributed to the problem as well. The chytrid’s spread and effects may be exacerbated by climate change – warmer temperatures dry the moist areas where amphibians live, causing stress that may lead to greater susceptibility to the disease.
For amphibians, the potential impact of chytrid fungus across all species is probably underestimated, and a significant number of amphibian species that have been described are too rare and too poorly known to assess their level of endangerment.
While there are 2,000 to 3,000 threatened amphibian species, many suffer from threats that we have the ability to mitigate in the wild, such as habitat destruction and over-collection.
This information came from:
http://www.amphibianark.org/education/what-are-amphibians/
http://www.amphibianark.org/about-us/aark-activities/planning-workshops/
(this link is about a program that helps track the amphibians in need of help and aids in helping them.)
To Continue To Frog Identification:
https://mayerimentgardens.wordpress.com/frogstoads/frog-identification/
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