Biodiversity
Biodiversity exists at three interrelated levels: species diversity, genetic diversity, and community-level diversity. When we talk about plant biodiversity, we refer to the full range of plant species, the genetic variation found within those species, and the biological communities formed by those species. For vascular plants, biodiversity includes all species of ferns, gymnosperms, flowering plants, and related smaller groups such as clubmosses and horsetails. The genetic variation found within populations and among populations arises through the mutation of individual genes or chromosomes and is rearranged by genetic recombination during the sexual process. Genetic variation is important not only for the survival and evolution of species; it is also important to people for breeding improved crop plants with higher yields.
Biological diversity also refers to all biological communities, including temperate forests, tropical forests, grasslands, shrub lands, deserts, freshwater wetlands, and marine habitats. Each of these biological communities represents an adaptation of plants to particular regimes of climate, soil, and other aspects of the environment. This adaptation involves ecosystem interactions of each biological community with its physical and chemical environment. For example, the ability of a forest community to absorb rain water and slowly release the water into streams and the ability of a swamp to process and detoxify polluted water are both aspects of ecosystem-level biological diversity that are of central importance to human societies.
This page contains 201 words.

Biodiversity article
Read the rest of this article.
This article contains 2,812 words
(approx. 9 pages at 300 words per page).