Biological diversity, or biodiversity, is the range of life on our planet. A more thorough definition is presented by botanist Peter H. Raven: “At the simplest level, biodiversity is the sum total of all the plants, animals, fungi and microorganisms in the world, or in a particular area; all of their individual variation; and all of the interactions between them. It is the set of living organisms that make up the fabric of the planet Earth and allow it to function as it does, by capturing energy from the sun and using it to drive all of life’s processes; by forming communities of organisms that have, through the several billion years of life’s history on Earth, altered the nature of the atmosphere, the soil and the water of our planet; and by making possible the sustainability of our planet through their life activities now” (Raven, 1994).

It is not known how many species occur on our planet. Presently, about 1.4 million species have been named. It has been estimated that there are perhaps 9 million more that have not been identified. What is known is that they are vanishing at an unprecedented rate. Reliable estimates show extinctions occurring at a rate several orders of magnitude above “background” in some ecological systems (Wilson, 1992; Hoose, 1981).

The reasons for protecting biological diversity are complex, but they fall into four major categories:

1. First, loss of diversity generally weakens entire natural systems. Healthy ecosystems tend to have many natural checks and balances. Every species plays a role in maintaining this system. When simplified by the loss of diversity, the system becomes more susceptible to natural and artificial perturbations. The chances of a system-wide collapse increase. In parts of the Midwestern United States, for example, it was only the remnant areas of natural prairie vegetation that kept soil intact during the dust bowl years of the 1930s (Roush, 1982).

Simplified ecosystems are almost always expensive to maintain. For example, when synthetic chemicals are relied upon to control pests, the target species are not the only ones affected. Their natural predators are almost always killed or driven away, exacerbating the pest problem. In the meantime, people are unintentionally breeding pesticide-resistant pests. A process has begun by which people become perpetual guardians of the affected area, thus requiring the expenditure of financial resources and human ingenuity to keep the system going.

2. A second reason for protecting biological diversity is that it represents one of our greatest untapped resources. Great benefits can be reaped from a single species. About 20 species provide 90% of the world’s food. Of these 20, just three—wheat, maize, and rice—supply over one-half of that food. American wheat farmers need new varieties every five to 15 years to compete with pests and diseases. Wild strains of wheat are critical genetic reservoirs for these new varieties. In 1970, for example, the U.S. corn crop was threatened by a new race of corn leaf blight that had reduced corn yields by 50% in many states. The gene that creates resistance to the blight was discovered in a wild strain of corn found only in Mexico. Without genetic variety within species, humans have much less potential to meet their own changing needs, and the species themselves have much less potential to adapt to changing environments. Further, every species is a potential source of human medicine. In 1980, a published report identified the market value of prescription drugs from higher plants at over $3 billion. Organic alkaloids, a class of chemical compounds used in medicines, are found in an estimated 20% of plant species. Yet only 2% of plant species have been screened for these compounds (Hoose, 1981).

3. The third reason for protecting diversity is that humans benefit from natural areas and depend on healthy ecosystems. The natural world supplies our air, our water, and our food and supports human economic activity. Further, humans are creatures that evolved in a diverse natural environment between forest and grasslands. People need to be reassured that such places remain. When people speak of “going to the country,” they generally mean more than getting out of town. For reasons of their own sanity and well being, they need a holistic, organic experience. Prolonged exposure to urban monotony produces neuroses, for which cultural and natural diversity is a cure.

Historically, the lack of attention to biological diversity and the ecological processes it supports has resulted in economic hardships for segments of the Great Lakes basin’s human population. The first Europeans who settled in the basin came in pursuit of fur-bearing animals, exhausted the populations, and were forced to move on to areas more rich in pelts. In the early 1800s, the virgin forests of the basin appeared to be without limit. They were harvested to support the building boom in the basin, often with a view to farming the cleared land. Frequently, poorer soils could not support agriculture after the forests were cleared, the farms failed, and the forests have yet to be fully regenerated. The Great Lakes commercial fishery reached its peak in the late 1800s. An entire industry, and the families it supported, suffered because of the introduction of exotic species, the over harvest of the lakes and pollution. Today, only pockets remain of the once large commercial fishery. (Botts and Krushelnicki, 1987)

4. The final reason for protecting biological diversity is that species and natural systems are intrinsically valuable. The above reasons have focused on the benefits of the natural world to humans. All things possess intrinsic value simply because they exist.

Source: Great Lakes Ecosystems: Conservation of Biological Diversity in the Great Lakes Basin Ecosystem: Issues and Opportunities. (September 2003). Chicago: U.S. Environmental Protection Agency. Great Lakes National Program Office. Retrieved April 16, 2005, from http://www.epa.gov/glnpo/ecopage/glbd/issues/intro.html#BiologicalDiversity

Biodiversity refers to the variety of life on Earth. It can be used to describe the diversity of life at different levels, including:

• Species Diversity: For example, eastern chipmunks, snapping turtles, American robins, humans, gray tree frogs, monarch butterfly, dandelions, and eastern white pine are all different species found in Michigan.

• Ecosystem Diversity: For example, forests, wetlands, coastal dunes, rivers, lakes, ponds, farmland, and urban areas are all ecosystems found in Michigan. Other types of ecosystems not found in Michigan include oceans, coral reefs, deserts, and tropical forests.

• Genetic Diversity: For example, no two people are exactly the same due to differences in their genes. This explains why people have different heights or hair color, and why some people are more or less resistant to certain diseases.