Published online by Cambridge University Press: 05 June 2012
What is biodiversity?
Biodiversity is the variety of life at all levels of its organization, including genes, species, ecosystems, and their interactions. The description of every component of biodiversity yields a hierarchical structure (Figure 9.1). At the finest level of resolution are genes and their different forms (i.e., alleles) found by the thousands to millions within the nucleus of each and every cell of every individual organism. Scaling up we would see morphological variation among individuals of the same species, which is the physical expression of each individual's underlying genetic constitution. Groups of individuals are distinguished by shared genetic traits distinct from those shared by other such groups. These groups, typically called evolutionary significant units or ESUs, are less likely to breed with members of other such groups usually because of some kind of barrier, such as a mountain range (Ryder 1986). ESUs often are the precursors to new species, which are groups of individuals that are incapable of successfully interbreeding due to physical or behavioral incompatibilities (Mayr 1963). Species assemble into communities, which are groups of species that predictably occur together, and are linked to one another through energy/nutrient transfer, competition, mutualisms, predation, and other interactions. These linkages can be extremely tight (e.g., mutualisms) or very diffuse (e.g., species that simply occur at the same place and time but do not effectively interact). Finally, a biome encompasses all communities found within a larger region, and represents the highest level of the biodiversity hierarchy.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.