A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura. The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar, but molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest. Frogs account for around 88% of extant amphibian species. They are also one of the five most diverse vertebrate orders. Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from taxonomy or evolutionary history.
Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology caused by teratogens. Teratogens are substances that may cause non-heritable birth defects via a toxic effect on an embryo or fetus. Defects include malformations, disruptions, deformations, and dysplasia that may cause stunted growth, delayed mental development, or other congenital disorders that lack structural malformations. The related term developmental toxicity includes all manifestations of abnormal development that are caused by environmental insult. The extent to which teratogens will impact an embryo is dependent on several factors, such as how long the embryo has been exposed, the stage of development the embryo was in when exposed, the genetic makeup of the embryo, and the transfer rate of the teratogen.
Hans-Hermann Hoppe is a German-American academic associated with Austrian School economics, anarcho-capitalism, right-wing libertarianism, and opposition to democracy. He is professor emeritus of economics at the University of Nevada, Las Vegas (UNLV), senior fellow of the Mises Institute think tank, and the founder and president of the Property and Freedom Society.
Since the 1980s, decreases in amphibian populations, including population decline and localized mass extinctions, have been observed in locations all over the world. This type of biodiversity loss is known as one of the most critical threats to global biodiversity. The possible causes include habitat destruction and modification, diseases, exploitation, pollution, pesticide use, introduced species, and ultraviolet-B radiation (UV-B). However, many of the causes of amphibian declines are still poorly understood, and the topic is currently a subject of ongoing research.
The Saint Louis River is a river in the U.S. states of Minnesota and Wisconsin that flows into Lake Superior. The largest U.S. river to flow into the lake, it is 192 miles (309 km) in length and starts 13 miles (21 km) east of Hoyt Lakes, Minnesota. The river's watershed covers 3,634 square miles (9,410 km2). Near the Twin Ports of Duluth, Minnesota and Superior, Wisconsin, the river becomes a freshwater estuary.
Poison dart frog is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are diurnal and often have brightly colored bodies. This bright coloration is correlated with the toxicity of the species, making them aposematic. Some species of the family Dendrobatidae exhibit extremely bright coloration along with high toxicity — a feature derived from their diet of ants, mites and termites— while species which eat a much larger variety of prey have cryptic coloration with minimal to no amount of observed toxicity. Many species of this family are threatened due to human infrastructure encroaching on their habitats.
The goliath frog, otherwise known commonly as the giant slippery frog and the goliath bullfrog, is a species of frog in the family Conrauidae. The goliath frog is the largest living frog. Specimens can grow up to 32 centimetres (12.6 in) in length from snout to vent, and weigh up to 3.25 kilograms (7.2 lb). This species has a relatively small habitat range in Cameroon and Equatorial Guinea. Its numbers are dwindling due to habitat destruction, collection for food, and the pet trade.
In 1938, the Austrian ethologist Karl von Frisch made his first report on the existence of the chemical alarm signal known as Schreckstoff in minnows. An alarm signal is a response produced by an individual, the "sender", reacting to a hazard that warns other animals, the receivers, of danger. This chemical alarm signal is released only when the sender incurs mechanical damage, such as when it has been caught by a predator, and is detected by the olfactory system. When this signal reaches the receivers, they perceive a greater predation risk and exhibit an antipredator response. Since populations of fish exhibiting this trait survive more successfully, the trait is maintained via natural selection. While the evolution of this signal was once a topic of great debate, recent evidence suggests schreckstoff evolved as a defense against environmental stressors such as pathogens, parasites, and UVB radiation and that it was later co-opted by predators and prey as a chemical signal.
A bioindicator is any species or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other small water crustaceans that are present in many water bodies can be monitored for changes that may indicate a problem within their ecosystem. Bioindicators can tell us about the cumulative effects of different pollutants in the ecosystem and about how long a problem may have been present, which physical and chemical testing cannot.
Ribeiroia is a genus of trematode parasites that sequentially infect freshwater snails in the family Planorbidae as first intermediate hosts, fish and larval amphibians as second intermediate hosts, and birds and mammals as definitive hosts. In North America, infection by Ribeiroia has been linked to amphibians with limb malformations. The connection between parasitic infection and limb malformations has generated questions about (a) whether parasite-induced malformations in amphibians are increasing, and (b) the consequences of such abnormalities for amphibian population conservation.
The pickerel frog is a small North American frog, characterized by the appearance of seemingly "hand-drawn" squares on its dorsal surface.
The mink frog is a small species of frog native to the United States and Canada. They are so named for their scent, which reportedly smells like a mink. The scent is more akin to that of rotting onions to those unfamiliar with mink. It is also sometimes referred to as the north frog.
Boana prasina is a species of frog in the family Hylidae. It is endemic to southeastern Brazil and is observed in many Brazilian states: Minas Gerais, Rio de Janeiro, and São Paulo, and possibly further south. The common name of Boana prasina is Burmeister's treefrog.
Ribeiroia ondatrae, or the frog-mutating flatworm is a parasite in the genus Ribeiroia which is believed to be responsible for many of the recent increases in amphibian limb malformations, particularly missing, malformed, and additional hind legs.
A pond is a small, still, land-based body of water formed by pooling inside a depression, either naturally or artificially. A pond is smaller than a lake and there are no official criteria distinguishing the two, although defining a pond to be less than 5 hectares in area, less than 5 metres (16 ft) in depth and with less than 30% with emergent vegetation helps in distinguishing the ecology of ponds from those of lakes and wetlands. Ponds can be created by a wide variety of natural processes, or they can simply be isolated depressions filled by runoff, groundwater, or precipitation, or all three of these. They can be further divided into four zones: vegetation zone, open water, bottom mud and surface film. The size and depth of ponds often varies greatly with the time of year; many ponds are produced by spring flooding from rivers. Ponds are usually freshwater but may be brackish in nature. Saltwater pools, with a direct connection to the sea to maintain full salinity, may sometimes be called 'ponds' but these are normally regarded as part of the marine environment. They do not support fresh or brackish water-based organisms, and are rather tidal pools or lagoons.
Pesticides in the United States are used predominantly by the agricultural sector, but approximately a quarter of them are used in houses, yards, parks, golf courses, and swimming pools.
The eastern mosquitofish was introduced to Australia in 1925, and had spread from the northeast coasts to New South Wales, southern Australia, and parts of Western Australia by 1934. By the 21st century, known populations of wild mosquitofish had occurred in every state and territory except the Northern Territory, found in swamps, lakes, billabongs, thermal springs, salt lakes, and ornamental ponds. Mosquitofish are considered a noxious pest, especially in New South Wales and Queensland, and it is illegal to release them into the wild or transport them live into any of the states or territories. Mosquitofish were introduced by military and local councils to control mosquito populations; however, there has been no evidence that Gambusia has had any effect in controlling mosquito populations or mosquito-borne diseases. Studies have shown that Gambusia can suffer mortalities if fed only on mosquito larvae, and survivors show poor growth and maturation. Gambusia typically eat zooplankton, beetles, mayflies, caddis flies, mites and other invertebrates; mosquito larvae make up only a small portion of their diet.
Developmental toxicity is any developmental malformation that is caused by the toxicity of a chemical or pathogen. It is the structural or functional alteration, reversible or irreversible, which interferes with homeostasis, normal growth, differentiation, development or behavior. Developmental toxicity is caused by environmental insult, which includes drugs, alcohol, diet, toxic chemicals, and physical factors.
Ectrodactyly, split hand, or cleft hand involves the deficiency or absence of one or more central digits of the hand or foot and is also known as split hand/split foot malformation (SHFM). The hands and feet of people with ectrodactyly (ectrodactyls) are often described as "claw-like" and may include only the thumb and one finger with similar abnormalities of the feet.
Strange Nature is a 2018 independent ecothriller film written and directed by special-effects artist Jim Ojala in his feature directorial debut.
