Australia's threatened species
Glossary
biodiversity. A measure of the variety of life. It is usually calculated from the number of species of organisms – although genera, families, classes and phyla can all be counted too.
community. All organisms inhabiting a common environment and interacting with one another.
ecosystem. A term used to encompass all the organisms in a community, together with the associated physical environmental factors (living and non-living) with which they interact.
emblematic species. Species that are closely associated by the public with a particular region, nation or continent, or that seem to ‘sum up’ the region in question. For example, kangaroos for Australia, pandas for China, or kiwis for New Zealand.
endangered. Used to refer to species (or higher levels of classification) that are likely to become extinct unless the various threats and pressures affecting them cease.
endemic. Describes a species (or other unit of classification) that occurs in one particular region in all months of the year, and in all years. For example, the platypus is endemic to southeast Australia, and malaria is endemic to parts of Africa.
extinct. Occurring no more. The word is usually used for species but can apply to any level of classification. Recent extinctions are hard to prove, and an ‘official’ limit of 50 years with no recorded sightings of the species is now used.
genetic diversity. The variety of different types of genes in a species or population. Genetic diversity is really a form of biodiversity.
habitat. 1. The place normally occupied by a particular organism or population. 2. The sum of all the factors that determine the existence of a community (eg, the freshwater habitat).
invertebrates. Usually defined as animals without backbones, invertebrates make up the vast majority of all animal species. Only fish, amphibians, reptiles, birds and mammals are not invertebrates. Insects, spiders, worms, slaters and many marine creatures such as corals, sponges and jellyfish are examples of invertebrates.
macropod. Literally meaning ‘big foot’, the word is used to describe kangaroos, wallabies and rat kangaroos.
rare. Used to describe species with small populations or a very restricted distribution. Rarity may be a natural characteristic of some species, but it can also come about because of various pressures, and thus be a worrying sign about the future viability of a species. A rare species is more likely to become endangered or extinct, and so must should be treated carefully in management plans.
regression. A mathematical relationship between two variables (eg, the height and weight of women in Australia). For simplicity, the relationship is often taken to be a linear one (ie, a straight line when plotted), but it can also be a curve. When the regression relationship for the variables is known, we can predict the approximate value of one variable from the value of the other.
species. Living things of the same kind that are potentially capable of breeding and producing fertile offspring. Theoretically, plants or animals of different species cannot interbreed. However, occasionally this does not hold true.
variable. Something that takes on different values that can be measured or counted. If one variable can be controlled exactly (such as the selling price of apples) then it is called an 'independent variable', while the remaining variable (in this case the number of apples bought) is called a 'dependent variable'
vulnerable. Sometimes used synonymously with endangered, but also used to refer to species believed likely to move into the endangered category within the next 25 years if no action is taken.
Page updated August 2006.