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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