Biodiversity

Biodiversity is a term used to represent the total number of all life forms on our planet. This term includes all existent varieties of microbes, plants, animals, and fungi and all the genetic information they represent. Biodiversity entered into popular use with the publication of a volume edited by E. O. Wilson in 1988, titled Biodiversity, and is a contraction of the term biological diversity. While there is no comprehensive global database of all species, there are descriptions of between 1.4 million and 1.75 million documented species (depending on your source), with estimates of as few as 2 million to as many as 50 million more species yet to be identified and classified. While this disparity in estimates testifies to our limited understanding of the ultimate extent of biodiversity, it is even more surprising to note that some experts believe that as many as three species per hour are being lost largely due to human activity. Ecologists generally agree that species loss is happening at a historically unparalleled rate and could claim as many as one third of all organisms over the next 50 years. Given the estimates, it is possible that more species could be lost over the next century than are currently known and described. The awareness of our lack of deep knowledge of biodiversity raises many questions for humanity on both philosophical and practical levels.

Comprehension of biodiversity is critical to a proper understanding of the concept of sustainability (see entry) in the immediate and abstract sense. Biodiversity is an ecological demonstration of W. Ross Ashby's law of requisite variety, introduced in 1956, which states that the greater the variety possessed by a system the greater the number of disturbances that system can absorb without failure. Ashby observed that as variety is reduced below a requisite level, systems begin to fail. Because all life on the planet is part of the same biosphere, or interconnected ecological system or ecosystem, the variety of life-forms, or biodiversity, helps ensure the sustainability of all life on the planet by helping absorb the disturbances encountered within our ecological system. As has been observed and demonstrated, the existence of life helps create the conditions to support life, a notable example being the production of oxygen by trees and of carbon dioxide by animal respiration, each required to support life for the other.

As biodiversity decreases, the law of requisite variety predicts that the resilience of the ecosystem will also decrease until at some point the ecosystem will fail. In isolated regional ecosystems, such as island ecologies, this prediction has been demonstrated: As the biodiversity falls below the requisite variety, the ecosystem fails for life-forms related to that specific system, and especially harmed are those life-forms higher up on the food chain and therefore dependent on a greater number of other life-forms for their continued existence. Biodiversity has particular impact for human populations because our species is dependent on many other species of plants, animals, fungi, and microbes. At this point, scientists and ecologists have no clear idea of what number of other species constitutes the minimum requisite variety in terms of the global ecosystem's ability to provide ecological [Page 173]services to the global population of living creatures. The United Nations Environment Programme (UNEP) has estimated ecosystem services to be worth between $16 trillion and $54 trillion annually. What is clear is that the human population, and our ability to adapt to most biological niches, has made species survival for many other life-forms on this planet increasingly difficult. In the expert opinion of some scientists, our planet is experiencing the greatest rate of species extinction in 65 million years. By all indications, human activity is either directly or indirectly the cause of this massive reduction in biodiversity.

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