The name thyroid-stimulating hormone ( TSH ) has been given to a substance found in the anterior pituitary gland of all species of animal so tested for its presence.

With their often complex reproductive needs and permeable skins, amphibians are often ecological indicators and in recent decades there has been a dramatic decline in amphibian populations of many species around the globe.

A caecilian's skin has a large number of transverse folds and in some species contains tiny embedded dermal scales.

The development of the young of Ichthyophis glutinosus, a species from Sri Lanka, has been much studied.

A number of causes are believed to be involved, including habitat destruction and modification, over-exploitation, pollution, introduced species, climate change, endocrine-disrupting pollutants, destruction of the ozone layer ( ultraviolet radiation has shown to be especially damaging to the skin, eyes, and eggs of amphibians ), and diseases like chytridiomycosis.

By its inclusion the order has grown enormously in number of species.

The group has more than 23, 000 currently accepted species, spread across 1620 genera and 12 subfamilies.

Each abalone species has a typical number of holes in the selenizone which remain open.

Although the family ( Amaranthaceae ) is distinctive, the genus has few distinguishing characters among the 70 species included.

The species Amaranthus palmeri ( Palmer amaranth ) causes the greatest reduction in soybean yields and has the potential to reduce yields by 17-68 % in field experiments.

It has the capacity to get to large heights and can outcompete native plant species around it.

Ailanthus are capable of forming thick blankets of roots and heavy shade to the extent that native species are prevented from being able to reclaim an area that has been logged or deforested, as well as areas that have been heavily developed.

Widespread usage of antibacterial drugs in hospitals has also been associated with increases in bacterial strains and species that no longer respond to treatment with the most common antibacterials.

Although there were low levels of preexisting antibiotic-resistant bacteria before the widespread use of antibiotics, evolutionary pressure from their use has played a role in the development of muiltidrug resistance varieties and the spread of resistance between bacterial species.

Lastly, abiotic stress has enabled species to grow, develop, and evolve, furthering natural selection as it picks out the weakest of a group of organisms.

It has been observed through a variety of environments that as the level of abiotic stress increases, the number of species decreases.

Australia has several indigenous plants which are popular among modern ayahuasqueros there, such as various DMT-rich species of Acacia.

Moreover they argued that some species have been created for the purpose of being sacrificed and eaten by humans, that it is normal for animals to kill and eat other animals, that agriculture, too, inevitably leads to the death of many animals, that plants are living beings as well and must still be destroyed, that we unintentionally and unknowingly destroy life forms all the time, and that a hunted animal has a fair chance to survive by killing the hunter.

Acid rain has eliminated insect life and some fish species, including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United States.

It has not been definitively established whether the existence of these brainless species indicates that the earliest bilaterians lacked a brain, or whether their ancestors evolved in a way that led to the disappearance of a previously existing brain structure.

No modern species should be described as more " primitive " than others, strictly speaking, since each has an equally long evolutionary history — but the brains of modern hagfishes, lampreys, sharks, amphibians, reptiles, and mammals show a gradient of size and complexity that roughly follows the evolutionary sequence.

The relationship between brain size, body size and other variables has been studied across a wide range of vertebrate species.

The brain of a shark shows the basic components in a straightforward way, but in teleost fishes ( the great majority of existing fish species ), the forebrain has become " everted ", like a sock turned inside out.

* Bisexual species, in biology, one that has members of two different distinct sexes ( e. g. humans ), opposed to unisexual ( only one sex present, always females )

As a result of its relief and geographic situation, the Ubaye Valley has an " abundance of plant and animal species ".

A number of fossil cryptobranchids have been found but there are only three living species, the Chinese giant salamander ( Andrias davidianus ), the Japanese giant salamander ( Andrias japonicus ) and the hellbender ( Cryptobranchus alleganiensis ) from North America.

Altogether, over two hundred toxins have been isolated from the limited number of amphibian species that have been investigated.

Many species have an erect woody stem which is covered with persistent dried leaves unless there have been fires, topped by a crown of long thin leaves.

Abalone have long been a valuable food source for humans in every area of the world where a species is abundant.

Prohibitions on commercial and recreational harvest of this species have been in place since 1996.

By 1987 a comprehensive survey of the phylum was completed: in all, 4516 species and 339 genera had been named.

In the recent years, several of the apicomplexan species have been selected for genome sequencing.

Polyynes, a subset of this class of natural products, have been isolated from a wide variety of plant species, cultures of higher fungi, bacteria, marine sponges, and corals.

Both species of anoa have been classified as endangered since the 1960s, and the population continues to decrease.

Around 620 species have been recognised so far, with may more undescribed.

Some birds, especially corvids and parrots, are among the most intelligent animal species ; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.

In Thailand, many populations of one freshwater species have been wiped out by an introduced species of snail.

Chemicals extracted from a marine bryozoan species have been investigated for treatment of cancer and Alzheimer's Disease, but analyses have not been encouraging.

Two species are described in the literature: A. ramidus, which lived about 4. 4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5. 6 million years ago ( late Miocene ).

This fossil was originally described as a species of Australopithecus, but White and his colleagues later published a note in the same journal renaming the fossil under a new genus, Ardipithecus.

The number of species recognized worldwide ranges between 30 and 130 with over 200 species-level taxa described.

Other common names for the blue whale have included Sibbald's rorqual ( after Sibbald, who first described the species ), the great blue whale and the great northern rorqual.

Authorities classify the species into three or four subspecies: B. m. musculus, the northern blue whale consisting of the North Atlantic and North Pacific populations, B. m. intermedia, the southern blue whale of the Southern Ocean, B. m. brevicauda, the pygmy blue whale found in the Indian Ocean and South Pacific, and the more problematic B. m. indica, the great Indian rorqual, which is also found in the Indian Ocean and, although described earlier, may be the same subspecies as B. m. brevicauda.

The words at the administration of Communion which, in the prayer book of 1549 described the Eucharistic species as ' The body of our Lorde Jesus Christe ...', ' The blood of our Lorde Jesus Christe ...' were replaced with the words ' Take, eat, in remembrance that Christ died for thee ..' etc.

It was one of many species described by Linnaeus in his 18th-century work Systema Naturae ( 1735 ).

The genus Candida and species C. albicans were described by botanist Christine Marie Berkhout in her doctoral thesis at the University of Utrecht in 1923.

About 40 % of all described insect species are beetles ( about 400, 000 species ), and new species are discovered frequently.

Some estimates put the total number of species, described and undescribed, at as high as 100 million, but a figure of 1 million is more widely accepted.

Beetles are by far the largest orders of insects, with 350, 000 – 400, 000 species in four suborders ( Adephaga, Archostemata, Myxophaga, and Polyphaga ), making up about 40 % of all insect species described.

Based on estimates for all 165 families, more than 358, 000 species of beetles have been described and are considered valid.

Most species ( about 62 %) are in six extremely diverse families, each with at least 20, 000 described species: Curculionidae, Staphylinidae, Chrysomelidae, Carabidae, Scarabaeidae, and Cerambycidae.

The smaller families account for 22 % of the total species – 127 families with fewer than 1000 described species and 29 families with 1000 – 6000 described species.

Chimpanzees have been described as highly territorial and are known to kill other chimps, although Margaret Power wrote in her 1991 book The Egalitarians that the field studies from which the aggressive data came, Gombe and Mahale, use artificial feeding systems that increased aggression in the chimpanzee populations studied, so might not reflect innate characteristics of the species as a whole.