An Introduction to Biodiversity

Biodiversity can be defined as the variation of life at all levels of biological organisation, from genes to species to ecosystems.

Within biodiversity, there are three main categorisations: genetic, organismal and ecological. First of all, genetic diversity refers to variations in the genetic coding that determines an individual’s characteristics within and between species -with such diversity being vital for species survival, evolution and adaptation.


Organismal diversity, on the other hand, encompasses the taxonomic hierarchy from individuals, to species, to genera and so forth, with a species often used as the most fundamental unit of diversity. Lastly, ecological diversity refers to diversity at different scales, from populations up to ecosystems and biomes.


The importance of preserving biodiversity cannot be solely ascribed to its intrinsic value, but also due to the ecosystem services (see Figure 1 for examples) and life support mechanisms which it supports. However, in spite of such value, biodiversity loss has accelerated in the last 30,000 years as a result of human activity and climate change, with the current rate of extinction thought to be 1000 times that of background extinction. Consequently, there have been increasing effort directed towards conservation action and research.


Figure 1 – Diagram of the services provided by ecosystem functioning.

“Untitled”, 2018, Graphic, CGIAR Research Program on Water, Land and Ecosystems. Source: (18/01/19)


Key Terms:


Background extinction – The standard rate of extinction present before humanity’s increased contribution.


Biome – A large community of flora and fauna occupying a major habitat.


Ecosystem – A community of interdependent organisms and the physical/chemical environment in which they inhabit.


Ecosystem Services – The societal benefits obtained from ecosystems.


Evolution – The process of how different organisms have developed as a result of environmental pressures selecting individuals better suited to them.


Genes – A unit of hereditary passed from parent to offspring, determining an offspring’s characteristics.


Genus (plural Genera) – A major subdivision in a used when categorising organisms usually consisting of more than one species.


Species – A group of similar individuals that are able to share genetic information and inter-breed.


Taxonomic hierarchy – The relative order of grouping organisms from species as the smallest unit to domain as the largest.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.