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 –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. –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.