Great aukThe great auk (Pinguinus impennis) is a species of flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus Pinguinus. It is not closely related to the birds now known as penguins, which were discovered later by Europeans and so named by sailors because of their physical resemblance to the great auk. It bred on rocky, remote islands with easy access to the ocean and a plentiful food supply, a rarity in nature that provided only a few breeding sites for the great auks.
Punctuated equilibriumIn evolutionary biology, punctuated equilibrium (also called punctuated equilibria) is a theory that proposes that once a species appears in the fossil record, the population will become stable, showing little evolutionary change for most of its geological history. This state of little or no morphological change is called stasis. When significant evolutionary change occurs, the theory proposes that it is generally restricted to rare and geologically rapid events of branching speciation called cladogenesis.
GradualismGradualism, from the Latin gradus ("step"), is a hypothesis, a theory or a tenet assuming that change comes about gradually or that variation is gradual in nature and happens over time as opposed to in large steps. Uniformitarianism, incrementalism, and reformism are similar concepts. In the natural sciences, gradualism is the theory which holds that profound change is the cumulative product of slow but continuous processes, often contrasted with catastrophism.
DeerA deer (: deer) or true deer is a hoofed ruminant mammal of the family Cervidae. The two main groups of deer are the Cervinae, including muntjac, elk (wapiti), red deer, and fallow deer; and the Capreolinae, including reindeer (caribou), white-tailed deer, roe deer, and moose. Male deer of all species (except the water deer), as well as female reindeer, grow and shed new antlers each year. In this, they differ from permanently horned antelope, which are part of a different family (Bovidae) within the same order of even-toed ungulates (Artiodactyla).
CladeIn biological phylogenetics, a clade (), also known as a monophyletic group or natural group, is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. In the taxonomical literature, sometimes the Latin form cladus (plural cladi) is used rather than the English form. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches.
InbreedingInbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious recessive traits resulting from incestuous sexual relationships and consanguinity. Animals avoid incest only rarely. Inbreeding results in homozygosity, which can increase the chances of offspring being affected by recessive traits.
Red wolfThe red wolf (Canis rufus) is a canine native to the southeastern United States. Its size is intermediate between the coyote (Canis latrans) and gray wolf (Canis lupus). The red wolf's taxonomic classification as being a separate species has been contentious for nearly a century, being classified either as a subspecies of the gray wolf Canis lupus rufus, or a coywolf (a genetic admixture of wolf and coyote). Because of this, it is sometimes excluded from endangered species lists, despite its critically low numbers.
Introduced speciesAn introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there by human activity, directly or indirectly, and either deliberately or accidentally. Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are considered naturalized.
Genetic diversityGenetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment.
Blue whaleThe blue whale (Balaenoptera musculus) is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue dorsally and somewhat lighter underneath. Four subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, B.
