Phyletic dwarfism

Last updated

Phyletic dwarfism is the decrease in average size of animals of a species. There are a few circumstances that often lead to species doing this. Lack of predators of smaller creatures can allow smaller members of a species to survive. The lack of resources to sustain a large population of larger animals can pick off the largest specimens. Available resources being more beneficial for smaller creatures can also do so.

These circumstances are common on islands, making insular dwarfism the most common form of phyletic dwarfism. Examples of this are the Channel Island fox, extinct dwarf elephants of Crete, and Brookesia micra , a minuscule chameleon from Madagascar. An noninsular example is the evolution of dwarfed marmosets and tamarins among New World monkeys. [1] Phyletic dwarfism may have also helped give rise to birds from their much larger dinosaur ancestors.

Related Research Articles

<span class="mw-page-title-main">Hamster</span> Subfamily of rodents (Cricetinae)

Hamsters are rodents belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera. They have become established as popular small pets. The best-known species of hamster is the golden or Syrian hamster, which is the type most commonly kept as a pet. Other hamster species commonly kept as pets are the three species of dwarf hamster, Campbell's dwarf hamster, the winter white dwarf hamster and the Roborovski hamster.

<span class="mw-page-title-main">Antelope</span> Term referring to an even-toed ruminant

The term antelope is used to refer to numerous species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do not form a monophyletic group, as some antelopes are more closely related to other bovid groups, like bovines, goats, and sheep, than to other antelopes.

<i>Ex situ</i> conservation Preservation of plants or animals outside their natural habitats

Ex situ conservation literally means, "off-site conservation". It is the process of protecting an endangered species, variety or breed, of plant or animal outside its natural habitat; for example, by removing part of the population from a threatened habitat and placing it in a new location, an artificial environment which is similar to the natural habitat of the respective animal and within the care of humans, example are zoological parks and wildlife sanctuaries. The degree to which humans control or modify the natural dynamics of the managed population varies widely, and this may include alteration of living environments, reproductive patterns, access to resources, and protection from predation and mortality. Ex situ management can occur within or outside a species' natural geographic range. Individuals maintained ex situ exist outside an ecological niche. This means that they are not under the same selection pressures as wild populations, and they may undergo artificial selection if maintained ex situ for multiple generations.

<span class="mw-page-title-main">Parma wallaby</span> Species of marsupial

The parma wallaby is a small, hopping, kangaroo-like mammal native to forests of southeastern Australia. About the size of a stout cat, it lives in dense shrub and is only active at night to feed on grasses and small plants. It is the smallest of the wallabies and carries its young in a pouch like other marsupials. Shy and elusive, it was believed extinct until rediscovery in the 1960s. It is threatened by habitat loss and is easily killed by non-native foxes.

<span class="mw-page-title-main">Foster's rule</span> Ecogeographical rule in evolutionary biology

Foster's rule, also known as the island rule or the island effect, is an ecogeographical rule in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment. For example, it is known that pygmy mammoths evolved from normal mammoths on small islands. Similar evolutionary paths have been observed in elephants, hippopotamuses, boas, sloths, deer and humans. It is part of the more general phenomenon of island syndrome which describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts.

<span class="mw-page-title-main">Campbell's dwarf hamster</span> Species of mammal

Campbell's dwarf hamster is a species of hamster in the genus Phodopus. It was given its common name by Oldfield Thomas in honor of Charles William Campbell, who collected the first specimen in Mongolia on July 1, 1902. It is distinguished from the closely related Djungarian hamster as it has smaller ears and no dark fur on its crown. Campbell's dwarf hamster typically has a narrow dorsal stripe compared to the Djungarian hamster and grey fur on the stomach. This hamster may be raised in captivity and kept as a small pet.

<span class="mw-page-title-main">African dwarf frog</span> Genus of amphibians

African dwarf frog is the common name for members of Hymenochirus, a genus of aquatic frog native to parts of Equatorial Africa. They are common in the pet trade and are often mistaken for the African clawed frog, a similar-looking frog in the same family. African dwarf frogs are also known as dwarf clawed frogs. Their common name is obtained from their place of origin and the claws on their hind legs.

<span class="mw-page-title-main">Island gigantism</span> Evolutionary phenomena leading to an increase of the size of species with insularity

Island gigantism, or insular gigantism, is a biological phenomenon in which the size of an animal species isolated on an island increases dramatically in comparison to its mainland relatives. Island gigantism is one aspect of the more general "island effect" or "Foster's rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies. This is itself one aspect of the more general phenomenon of island syndrome which describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts. Following the arrival of humans and associated introduced predators, many giant as well as other island endemics have become extinct. A similar size increase, as well as increased woodiness, has been observed in some insular plants such as the Mapou tree in Mauritius which is also known as the "Mauritian baobab" although it is member of the grape family (Vitaceae).

Extraterrestrial is a British-American two-part television documentary miniseries, aired in 2005 in the UK by Channel 4, by the National Geographic Channel in the US on Monday, May 30, 2005 and produced by Big Wave Productions Ltd. The program focuses on the hypothetical and scientifically feasible evolution of alien life on extrasolar planets, providing model examples of two different fictional worlds, one in each of the series's two episodes.

<span class="mw-page-title-main">Insular dwarfism</span> Form of phyletic dwarfism occurring on islands

Insular dwarfism, a form of phyletic dwarfism, is the process and condition of large animals evolving or having a reduced body size when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf breeds, called dwarfing. This process has occurred many times throughout evolutionary history, with examples including dinosaurs, like Europasaurus and Magyarosaurus dacus, and modern animals such as elephants and their relatives. This process, and other "island genetics" artifacts, can occur not only on islands, but also in other situations where an ecosystem is isolated from external resources and breeding. This can include caves, desert oases, isolated valleys and isolated mountains. Insular dwarfism is one aspect of the more general "island effect" or "Foster's rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies. This is itself one aspect of island syndrome, which describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts.

<span class="mw-page-title-main">Live food</span> Pet owner or zoo practice

Live food is living animals used as food for other carnivorous or omnivorous animals kept in captivity; in other words, small preys fed alive to larger predators kept either in a zoo or as a pet.

<span class="mw-page-title-main">Palawan stink badger</span> Species of carnivore

The Palawan stink badger, pantot or tuldo in the Batak language, is a carnivoran of the western Philippines named for its resemblance to badgers, its powerful smell, and the largest island to which it is native, Palawan. Like all stink badgers, the Palawan stink badger was once thought to share a more recent common ancestor with badgers than with skunks. Recent genetic evidence, however, has led to their re-classification as one of the Mephitidae, the skunk family of mammals. It is the size of a large skunk or small badger, and uses its badger-like body to dig by night for invertebrates in open areas near patches of brush. While it lacks the whitish dorsal patches typical of its closest relatives, predators and hunters generally avoid the powerful noxious chemicals it can spray from the specialized anal glands characteristic of mephitids.

<span class="mw-page-title-main">Hațeg Island</span> Prehistoric island

Hațeg Island was a large offshore island in the Tethys Sea which existed during the Late Cretaceous period, probably from the Cenomanian to the Maastrichtian ages. It was situated in an area corresponding to the region around modern-day Hațeg, Hunedoara County, Romania. Maastrichtian fossils of small-sized dinosaurs have been found in the island's rocks. It was formed mainly by tectonic uplift during the early Alpine orogeny, caused by the collision of the African and Eurasian plates towards the end of the Cretaceous. There is no real present-day analog, but overall, the island of Hainan is perhaps closest as regards climate, geology and topography, though still not a particularly good match. The vegetation, for example, was of course entirely distinct from today, as was the fauna.

<span class="mw-page-title-main">Cozumel raccoon</span> Species of critically endangered raccoon

The Cozumel raccoon is a critically endangered species of island raccoon endemic on Cozumel Island off the coast of the Yucatan Peninsula, Mexico. It is also called the pygmy raccoon, dwarf raccoon, Cozumel Island raccoon, and Cozumel raccoon bear.

<span class="mw-page-title-main">Malagasy hippopotamus</span> Extinct species of hippopotamus

Several species of Malagasy hippopotamus lived on the island of Madagascar but are now believed to be extinct. The animals were very similar to the extant hippopotamus and pygmy hippopotamus. The fossil record suggests that at least one species of hippopotamus lived until about 1,000 years ago and other evidence suggests that the species may have survived until much more recently. The taxonomy of these animals is not resolved and not widely studied.

Island ecology is the study of island organisms and their interactions with each other and the environment. Islands account for nearly 1/6 of earth’s total land area, yet the ecology of island ecosystems is vastly different from that of mainland communities. Their isolation and high availability of empty niches lead to increased speciation. As a result, island ecosystems comprise 30% of the world’s biodiversity hotspots, 50% of marine tropical diversity, and some of the most unusual and rare species. Many species still remain unknown.

<span class="mw-page-title-main">Vermin</span> Insects and animals that spread diseases or destroy crops or livestock

Vermin (colloquially varmint(s) or varmit(s)) are pests or nuisance animals that spread diseases or destroy crops, livestock, and property. Since the term is defined in relation to human activities, which species are included vary by region and enterprise.

Dwarf, dwarfs or dwarves may refer to:

<i>Balaur bondoc</i> Extinct genus of dinosaurs

Balaur is a genus of theropod dinosaur from the late Cretaceous period, in what is now Romania. It is the type species of the monotypic genus Balaur, after the balaur, a dragon of Romanian folklore. The specific name bondoc means "stocky", so Balaur bondoc means "stocky dragon" in Romanian. This name refers to the greater musculature that Balaur had compared to its relatives. The genus, which was first described by scientists in August 2010, is known from two partial skeletons.

<span class="mw-page-title-main">Island syndrome</span> Set of phenotypical features likely to occur in geographically-isolated populations

Island syndrome describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts. These differences evolve due to the different ecological pressures affecting insular species, including a paucity of large predators and herbivores as well as a consistently mild climate.

References

  1. Perelman, P.; et al. (2011). "A Molecular Phylogeny of Living Primates". PLOS Genetics. 7 (3): 1–17. doi: 10.1371/journal.pgen.1001342 . PMC   3060065 . PMID   21436896.