6–3 Biodiversity

Biological diversity, or biodiversity, is the sum of all the kinds of
organisms in the biosphere. There are several types of diversity:
• Ecosystem diversity is all of the habitats, communities, and
ecological processes in ecosystems.
• Species diversity is the number of different species in the
biosphere.
• Genetic diversity is the genetic information carried in all
living things on Earth.

Biodiversity is one of Earth’s great natural resources. Human
activity can reduce biodiversity by altering habitats, hunting
species to extinction, introducing pollution into food webs, or
introducing foreign species into new environments.
• As humans destroy habitats, the species living in those
habitats may die out. Development can split habitats, a
process called habitat fragmentation. The smaller the
pieces of habitat, the less likely its species can survive.
• Extinction is the disappearance of a species from all or part of
its range. An endangered species is one whose population
size is declining in a way that places it in danger of extinction.
• Toxic compounds build up in the tissues of organisms. These
concentrations get larger in living things at higher trophic
levels. This is called biological magnification.
• Plants and animals brought into an area from other places
can become invasive species. Invasive species can multiply
quickly if their new habitat lacks parasites and predators to
control their numbers.

Conservation is the wise management of natural resources.
Today, conservation efforts focus on protecting entire ecosystems
as well as single species. Protecting an ecosystem
will ensure that the natural habitats and the interactions of
many different species are preserved at the same time.

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