This involves making judgements about just how much variation is natural between individuals within a species, and how much represents differences between species. The taxonomist then gives formal names to newly recognised species, along with a description that emphasises attributes most useful to distinguish between species. To be accepted throughout the community of scientists, the names and descriptions must be published in one of a limited number of scientific journals, which subject manuscripts to peer review by other experts before accepting them for publication. While kangaroos are very familiar to Australians, it is necessary to inform scientists all over the world precisely how this species is related, not only to other kangaroos, but to all other living things as well. This list is like scientific shorthand.
Internal parasites can have major effects on their hosts.
A prime suspect is a mite that affects the breathing efficiency of heavily infected birds. Genetic Diversity Biodiversity exists within species as well as between species, at the level of genetic diversity. Within almost all species there exists extensive inherited variation that makes each individual organism genetically unique. This variation is important in several ways. In the short term, subtle differences among individuals or populations within a particular species may allow them to adapt to, and therefore exploit, a variety of different environments.