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Biodiversity

Miss Napolitano & Mrs. RodriguezEnvironmental Science

+Biodiversity

Biodiversity: the number of different species in a given area Short for “biological diversity”

There are ~1.7 million species on Earth Most are insects – yuck! Not all species are known (collected/described

scientifically)

+Keystone vs. Flagship Species

Keystone species: species that are critical to the functioning of an ecosystem Ex: sea otter – loss leads to loss of kelp beds

Flagship species: well-known, popular species Usually used to attract support for conservation

Keystone species are not necessarily the best-known species in the environment!

+Benefits of Biodiversity

Genetic diversity increases the chance that some members will survive environmental changes

Variety of organisms used for food, clothing, shelter, & medicine ¼ of prescription drugs derived from plants

*Wild Pharmacy!

+Endangered vs. Threatened Species

There have been 5 mass extinctions in Earth’s history Takes millions of years for biodiversity to come back after

a mass extinction

Large populations that easily adapt are less likely to become extinct Ex: cockroaches, rats

Threatened species: species with a declining population

Endangered species: species that is likely to become extinct if protective measures not taken

+Humans & Extinction

Humans accelerate rate of extinction due to habitat destruction, pollution, & overharvesting of species

Introduce exotic species – species that are not native to a particular area

Continue poaching – illegal hunting, fishing, harvesting, or trading of wildlife

+Areas of Critical Biodiversity

Different parts of the world have different amounts of species diversity

Lots of endemic species: native species found within a limited area

~1/2 of Earth’s species live in tropical rain forests Only make up ~7% of Earth’s land surface Most species have never been described

Coral reefs very diverse but ~60% are threatened by human activities Ex: overfishing, pollution

Organisms on islands become isolated, adapt to surroundings, & evolve into new species

+Biodiversity Hotspots

Biodiversity hotspots: the most threatened areas of high species diversity

Have high numbers of endemic species but threatened by human activities

Most have lost at least 70% of original vegetation

3 hotspots in the US: California floristic province, Caribbean, & Polynesia/Micronesia

Lots of biodiversity in the US because many different types of environments & ecosystems

+The Future of Biodiversity – Conservation Efforts

Captive-Breeding Programs Breeding species in captivity & reintroducing into natural

habitats

Preserving genetic material in germ-plasm banks

Zoos, aquariums, parks, & gardens

Problems with captive species: Organisms have more difficulty surviving or reproducing in

wild Vulnerable to infectious disease Small populations at risk of genetic disorders from inbreeding

Focus is now on conserving ecosystems instead of individual species, especially hotspots.

+Legal Protection for Species – Endangered Species Act (1973)

US Fish & Wildlife Service (USFWS) compiles list of all endangered & threatened species – 1, 272 species in 2005

Anyone who harms, buys, or sells any part of listed species is subject to fines

Federal government cannot carry out projects that jeopardizes listed species

Recovery plan developed for each listed species Protect/restore habitats Controversial – does not always benefit humans Habitat conservation plan: protects species through

trade-offs or cooperation agreements

+International Cooperation

International Union for the Conservation of Nature and Natural Resources (IUCN): conservation on international level Red Lists of species in danger of extinction developed Advises governments on how to manage natural

resources

United Nations Conference on Environment and Development (1992) AKA Earth Summit 100 world leaders with 30,000 other participants Biodiversity Treaty: preserves biodiversity &

ensures sustainable & fair use of genetic resources in all countries

+Ecotourism

Ecotourism: tourism that supports the conservation and sustainable development of ecologically unique areas