2. Species Resources and Biodiversity

Assessment of the number of different organisms that live on this planet is plagued with difficulties. Biologists lack a precise definition of what exactly defines a species. The concept of a species often refers to a population of physically similar individuals that can successfully mate between each other, but cannot produce fertile offspring with other organisms. However, many species are composed of a number of distinct populations that can interbreed even though they display physiological and anatomical differences.

The concept of biodiversity has been developed by biologists to overcome some of the difficulties of species concept. To accomplish this task, biodiversity describes the diversity of life at the following three biological levels:

Genetic Level or Genetic Diversity - Genetic diversity refers to the total number of genetic characteristics expressed and recessed in all of the individuals that comprise a particular species

Species Level or Species Diversity - Species diversity is the number of different species of living things living in an area. As mentioned above, a species is a group of plants or animals that are similar and able to breed and produce viable offspring under natural conditions.

Ecosystem Level or Ecosystem Diversity - Ecosystem diversity is the variation of habitats present in a given area. An ecosystem consists of all living and non-living things in a given area that interact with one another.

The biodiversity found on Earth today is the product of 3.5 billion years of evolution . In fact, the Earth supports more biodiversity today than in any other period in history.

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