Download Biodiversity

Humans in the Biosphere
Biodiversity
&
Charting a Course for the Future
Biodiversity
• Biodiversity = The sum total of all organisms
in the biosphere.
• Ecosystem diversity = all of the habitats,
communities, and ecological processes of the
living world.
• Species diversity = The number of different
species in the biosphere.
• Genetic diversity = Sum total of the genetic
information carried by all organisms.
Threats to Biodiversity
• Human activity
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Altering habitats
Hunting species to extinction
Introducing toxic compounds into the food web
Introducing foreign species into an environment
• Extinction=when a species disappears
• Endangered species = the population of a
species declines such that it puts the species
in danger of extinction.
Threats to Biodiversity Habitat Alteration
• Habitat fragmentation= the
development of land often splits
ecosystems into pieces.
– Splits species into “biological islands”
– The smaller the island the fewer the
species.
– The smaller the island the more vulnerable
species are to changes in their
environment.
Threats to Biodiversity Hunting
• Hunting can push a species to
extinction.
• Hunting laws are difficult to enforce.
Threats to Biodiversity - Pollution
• Example: DDT
– A pesticide
• Nonbiodegradable=never broken down by bacteria, plants or
animals
• When consumed by an organism it is never eliminated from
their body.
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When sprayed it drained into rivers and streams.
Aquatic plants picked up DDT from the water.
Herbivores eat many aquatic plants.
Carnivores eat the herbivores.
• Biological magnification = concentrations of a
harmful substance increase at higher trophic
levels in a food chain or food web.
Threats to Biodiversity Introduced Species
• Foreign species are introduced into
habitats.
• Invasive species=foreign species that
reproduce rapidly.
– No predators or parasites to control their
population
Water Hyacinth
Threats to Biodiversity Introduced Species
• Example
– Gypsy moths
– once contained in a research facility on the
east coast of the United States until they
escaped in 1869
– caused the destruction of entire forests by
eating the leaves off of the trees
Conserving Biodiversity
• Conservation=management of natural
resources, including the preservation of
habitats and wildlife.
• Captive breeding programs, protect land
as parks or reserves, marine
sanctuaries.