Biodiversity : Glossary

There are 62 documents in this section.

  • Amphibian

    10 April 2001

    Common name for any animal of the vertebrate class lying between fishes and reptiles on the evolutionary scale. Emerging from the oceans almost 408 million years ago, amphibians were the first vertebrates (animals with a backbone) to live on land. The class, with about 4,400 existing species, includes three living orders: the tailed amphibians, consisting of the salamanders (including newts) and sirens; the tailless amphibians, which include frogs and toads; and the caecilians, which are worm-like amphibians that are limbless and blind.With their slender bodies and long tails, some amphibians, such as the salamanders, may be mistaken for lizards and other reptiles. Unlike reptiles, however, amphibians have no scales, and most must stay close to water to survive.

  • Animal

    10 April 2001

    Any member of the kingdom Animalia, which comprises all multicellular organisms that obtain energy by ingesting food and that have cells organized into tissues. Unlike plants, which manufacture nutrients from inorganic substances by means of photosynthesis, or fungi, which feed by absorbing organic matter in which they are usually embedded, animals actively acquire their food and digest it internally. Associated with this mode of nutrition are many of the additional features that readily distinguish most animals from other life forms. Specialized tissue systems permit animals to move about freely in search of food or, for those that are fixed in place during most of their lives (sessile animals), to draw the food towards themselves. The well-developed nervous systems and complex sense organs that have evolved in most animals enable them to monitor the environment and, in association with specialized movements, to respond rapidly and flexibly to changing stimuli.Almost all animal species, in contrast with plants, have a limited growth pattern and reach a characteristically well-defined shape and size at maturity. Reproduction is predominantly sexual, with the embryo passing through a blastula phase.

  • Mammal,

    10 April 2001

    Common name applied to any warm-blooded animal belonging to the class that includes human beings and all other animals that nourish their young with milk, are covered with varying amounts of hair, and possess a muscular diaphragm. The class Mammalia, which is represented by about 4,600 living species, is usually divided into three subclasses: the monotremes (egg-laying mammals), the marsupials (usually mammals with pouches), and the placental mammals. The majority of mammals are placental mammals. Mammals have the most highly developed nervous systems, including the brain, of all animals. Most members of the group have four appendages, usually legs. These may be adapted for use as swimming appendages, as in seals, or as wings, as in bats. Some types, however, have two limbs that have been reduced to small vestiges beneath the skin, as in whales, or have been lost altogether, as in sea cows. All mammals, except the monotremes, produce live young that undergo the early stages of development within the body cavity of the mother.

  • Endemic species

    16 March 2001

    Those species that are native to a certain region with restricted distributions and within in restricted range. Outside that restricted range (such as an ecosystem island, or within country boundaries) an endemic species is found nowhere else on earth.

  • Biodiversity loss (local)

    16 March 2001

    The loss of local breeding populations and/or their habitat, and thus the likely loss of genetic variations and reserve individuals.

  • Biological invasions

    16 March 2001

    Processes by which species become established in ecosystems to which they are not native. These species are commonly called biological invaders, invasive species or invading species. They are often weeds, pests and disease-causing organisms.

  • Breeding populations

    16 March 2001

    Groups of individual plants or animals that tend to reproduce among themselves and much less frequently with individuals from other members of the same species. As important sources of migrants and their genetic variability, these separated sub-populations can prove critical to the survival of a species as a whole.

  • Domestic species

    16 March 2001

    Species in which the evolutionary process has been manipulated by humans to meet human needs.

  • Habitat

    16 March 2001

    The particular environment (e.g. tropical moist forest) in which a species or breeding population naturally lives.

  • Precautionary principle

    16 March 2001

    The principle of prevention being better than cure, applied to potential environmental degradation.