- Biodiversity
Biological diversity, or "biodiversity," is the term used to describe the variety of life on earth. It encompasses all the animals, plants and microorganisms that exist on the planet, the genetic variety within these species and the variety of ecosystems they inhabit. Biodiversity can exist at three levels.
Species diversity is the variety of species of animals, plants and microorganisms on Earth or in a given area capable of reproducing fertile offspring.

Genetic diversity is the variety of genetic characteristics found within a species and among different species. Variations in hair and eye color, height and nose size are examples of genetic diversity found in humans.

Ecosystem diversity is the variety of natural systems found in a region, a country and on the planet. A farm field and a mountain are examples of two different ecosystems found in Kentucky.

Is biodiversity being threatened? (a state by state list)

The Earth's biodiversity has been in a constant state of change as long as life has existed on the planet. Periodic natural events such as volcanoes, meteor impacts and glaciers have disturbed ecosystems and led to extinction of species, thereby reducing biodiversity. As civilization developed, humans became an increasingly important influence. In today's world, biodiversity is threatened directly and indirectly by such human activity as:

Disturbance of ecosystems - Each of the world's ecosystems consists of a community of animals, plants and microorganisms and the sunlight, air, water, soil and minerals they need to survive. These systems exist in a delicate balance. Each component of the system has a special role. Any disruption of the balance can cause a ripple of disruptions, threatening parts or all of the ecosystem.

Pollutants dumped into the air, soil or water, introduction of nonnative species and atmospheric warming (the greenhouse effect) can harm biodiversity.

Destruction of habitat - Portions of ecosystems or entire ecosystems can be destroyed through the conversion of natural land and sea areas to other uses. This loss of animal and plant habitat leads directly to the loss of species. The conversion of Canadian wetlands to agricultural land is a good example of habitat destruction and loss of biodiversity.

Over-exploitation of animal and plant species - Many species are gathered by humans for fun, food, sources of medicine and raw materials for industry. Unwise use or over-exploitation can threaten the continued viability of individual species.

Agricultural and forestry practices - Today's farmers tend to cultivate a limited number of high-yield crop varieties and raise a limited number of breeds of livestock. Older varieties are in danger of disappearing as a result. These modern systems replace a more diverse natural ecosystem.

Imported exotic animals - These species are endangering the biodiversity of the North American continent. Exotic species -from non-native fish to various plants, bugs and shellfish - have found their way into the country in numerous ways, such as by clinging to ships, burrowing into wooden shipping crates, in food, aboard aircraft or in water discharged from foreign freighters. These unwanted pests “threaten to wreak major economic and environmental havoc” unless they are brought under control or kept out of the country altogether, U.S.Agriculture Secretary Dan Glickman said.

Is biodiversity important? Everything that lives in an ecosystem is part of the web of life, including humans. Each species of vegetation and each creature has a place on the earth and plays a vital role in the circle of life. Plant, animal, and insect species interact and depend upon one another for what each offers, such as food, shelter, oxygen, and soil enrichment.

Maintaining a wide diversity of species in each ecosystem is necessary to preserve the web of life that sustains all living things. In his 1992 bestseller, "The Diversity of Life," famed Harvard University biologist Edward O. Wilson -- known as the "father of biodiversity," -- said, "It is reckless to suppose that biodiversity can be diminished indefinitely without threatening humanity itself."

Protecting biodiversity is not free, saving animal and plant species can cost humans money, jobs, and even change the way we live. Recently several species of salmon which live in the Northwest U.S. were placed on the endangered species list. These fish are now protected by Federal regulations which will change the way the people in that area live. Decisions such as these can be made within a Cost/Benefit analysis framework. What is the cost to save an endangered species? What is the benefit in saving an endangered species? Is the cost proportional to the benefit? These are decisions you will have to make about your and your childrens' lives.

If we are to understand how we are changing the world's biodiversity, we must understand what biodiversity exists. Decisions must be made based scientific knowledge of the nature and importance of the biodiversity that surrounds us.

How much Biodiversity is there? The Five Kingdoms of Life.