Image Source Wild Display at the Melbourne Museum.

It is important for biologists to classify living organisms so species can identified and organised into groups according to their common features. The National Science Foundation’s “Tree of Life” project estimates that there could be anywhere from 5 million to 100 million species on the planet, but science has only identified about 2 million. Of these two million, the IUCN red list estimates that over 17, 000 species are in one form or another threatened with extinction today. So as fast as taxonomists are identifying new specimens, we are losing known species to habitat loss, introduced pests, pollution, overkill and climate change.

We often hear about threatened extinction of some conspicuous animals or plants, but it is usually not realized that each large species is host to many species of parasites, some of them specific to that host species and therefore doomed to extinction with it. The human species, for example, is host to far more than 100 parasite species, quite a few of these only found in humans. Species have not evolved in isolation – think of the co-evolution of flowering plants and their pollinators, toxic plants and their predators and animal camouflage.

This Chapter of work includes the Linnaean system of naming organisms, binomial nomenclature (Genus species system), heirarchical grouping (Kingdom, Phylum, Class, Order, Family, Genus and Species), dichotomous keys and cladograms. This site has some interesting mnemonics to remember biological terms for your upcoming exams.