Biodiversity Basics

What is Biodiversity?

All life on earth is part of one great, interdependent system. Living components interact with and depend on the non-living components of the planet: the atmosphere, oceans, freshwater, rocks and soils. Humans depend totally on this community of life, of which we are an integral part. Biological diversity, or biodiversity, is the variety of all life in Earth. It is the blanket term for the natural biological wealth that underlies life on Earth.

Biodiversity may be examined at three, interrelated levels:

Species biodiversity: The variety of species of plants and animals within a defined area (for example, a list of plant and animal species found within the Piedmont, or within a Brazilian rainforest)
Genetic diversity: The variety of genes within a species of plant or animal, or within a particular population of a species. Diversity within a species allows for adaptations of that species. Problems, such as interbreeding, can occur when too few individuals of a species are available. Reduced genetic diversity often yields troublesome traits such as lethal genes.
Ecosystem diversity: The variety of plant and animal communities within a defined area, such as a biome or ecoregion.

Other Important Terms

Habitat: the place and conditions that provide a species with whatever it needs to survive. The four components of habitat are food, water, shelter and space. These things must be available in the proper arrangement to meet a species’ needs.

Community: an area and all the species that live and interact within it.

Ecosystem: the sum of interactions between the living (biotic) and non-living (abiotic) components in a particular region. Biotic elements include plants and animals. Abiotic elements include soils, water and energy sources. An ecosystem can be small, such as a pond, or very large, such as a rainforest ecosystem. Some people consider the Earth itself to be an ecosystem.

Ecoregion: a geographically distinct area within a biome that is characterized by climate, vegetation, terrain, soils, and the types of communities that live there. For example, the Sonoran Desert constitutes an ecoregion.

Biome: a large region characterized by the types of plants that dominate the area. For example, deserts, forests, and grasslands are recognized as distinct biomes.

Ecological processes: processes that play an essential role in maintaining ecosystem integrity. Three fundamental ecological processes are water cycling, nutrient cycling and energy flow.

Why Do We Need Biodiversity?

We value biodiversity in many ways and for many reasons. Following are three major ways that we rely on biodiversity:

Ecosystem services

Water filtration (wetlands) and cycling
Soils formation and protection
Nutrient storage and cycling
Pollution breakdown and absorption
Contribution to climate stability
Recovery from events such as floods, droughts and hurricanes

Practical uses

Food
Medicine
Wood products
Breeding stocks and population reservoirs
Future resources such as food crops, medicines and fibers

Social uses

Consumptive recreation (hunting)
Non-consumptive recreation (hiking, birdwatching)

Cultural practices

Decorative uses (ornamental plants)

Major threats to biodiversity

Large-scale clearing and burning of forests
Overharvest of plants and animals
Indiscriminate use of pesticides
Draining and filling of wetlands
Air and water pollution
Conversion of wild lands to agricultural and urban uses

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