Ch. 10 Biodiversity

Section 10-1: What is Biodiversity? Discussion Question: How do you define or describe biodiversity?

What is biodiversity? Biodiversity – number of different species in a given area Extinction – when last members of a species die 1.7 million known species (mostly insects) Another 8 million estimated unknown species -See the chart on page 259 for estimated numbers of species

Levels of diversity Species diversity - number of different species (most studied) Ecosystem diversity – variety of habitats, communities, and ecological processes within an ecosystem Genetic diversity – all the different genes within a population

Benefits of Biodiversity Healthy ecosystems depend on all of the species within them Maintains balanced cycles of energy and nutrients When too many species are taken from a food web it will collapse

Benefits of biodiversity, cont. Keystone species – critical to maintaining balance within an ecosystem, disproportional role in the health of an ecosystem Sea otter – eats sea urchins which eat kelp Sea otter is hunted almost to extinction, sea urchins overpopulate, kelp beds are eaten away

More benefits Recreation Ethics Species and population survival Ecotourism Ethics All species have a right to exist Species and population survival Genetic diversity within a species increases the chance that some individuals will survive environmental changes When populations shrink, genetic diversity shrinks Medical, industrial, agricultural use ¼ of prescribed drugs come from plants Antibiotics come from fungi Unknown uses for biological material Food

Pharmaceutical Benefits See Table 1 on p. 261 for a list of medicines derived from plants

Section 10-2: Risks to Biodiversity Discussion Question: In what ways do humans cause a decrease the earth’s biodiversity?

Extinctions Mass extinction – extinction of many species within a short period of time 65 million years ago: climate and environmental changes caused half of the species to die Millions of years to rebound from mass extinctions Current extinctions – we are in the midst of another mass extinction caused by humans 1800 -2100: 25% of species extinct (predicted)

Species prone to extinction Species at risk – small populations in small areas migrating species species that need large or special habitats those exploited by humans Endangered species – likely to become extinct if protective measures are not used Threatened species – declining population that will likely become endangered without protective measures See Table 3 on p. 264 for threatened and extinct species

How do humans cause extinctions? 1. Destruction of habitats – causes 75% of current extinction Habitat destroyed to build homes and to harvest resources Florida panther – down to less than 100 Introduction of nonnative species – exotic species threaten native species because they have no natural defenses

How do humans cause extinctions? 3. Pollution – pesticides, cleaning agents, drugs are making their way into food webs 4. Overharvesting species – through hunting, harvesting, and poaching Poaching – illegal hunting, fishing, harvesting and trading of wildlife

Areas of critical biodiversity Areas with large portion of endemic species (native to and found in limited area) Tropical Rainforests – cover 7% of the earth and contain over half of world’s species

Areas of critical biodiversity Coral Reefs and Coastal Ecosytems – small part of marine environment but contain the majority of species Poorly studied and not well protected, high tourism 60% are threatened serve as migration routes, thus provide link between aquatic and terrestrial ecosystems Islands – very distinct species that have evolved over time, not found anywhere else

Biodiversity Hotspots Biodiversity hotspots: the most threatened areas of high species diversity 25 areas around the world: see figure 9 on p. 268 Most have lost 75% of original vegetation Mostly tropical rainforests, coastal areas, and islands Examples: Madagascar, Phillippines, New Zealand

Biodiversity in the United States Wide variety of ecosystems Florida Everglades, the CA coast, Hawaii, Midwestern prairies, forests of the Pacific Northwest Unusually high numbers of freshwater fishes, mussels, snails, and crayfish See Figure 10 on p. 269 for at-risk species in the US

Section 10-3: The Future of Biodiversity Discussion Question: What are ways in which biodiversity is protected?

Ways to save species 1. Captive Breeding Programs – breeding in captivity and then reintroducing the population back into its natural habitat Example: California Condor (read about on p. 270) 2. Preserving Genetic Material – storing germ plasm (genetic materials of plants and animals) -use the germ plasm for future research or species recovery efforts -stored ad seeds, sperm, eggs, or pure DNA 3. Zoos, Aquariums, Parks and Gardens – often house the last remaining individuals of a species museums of the world’s biodiversity

Ways to save species Problems with these methods: 1. sometimes captive species don’t reproduce 2. small populations are vulnerable to genetic disorders from inbreeding 3. these methods should be a last resort

Preserving habitats and ecosystems Most effective way is to preserve habitats which often means preserving large areas of land But, some species live in very small habitats and could become extinct due to a single natural disaster

Preserving habitats and ecosystems Conservation strategies 1. Protect entire ecosystems rather than individual species 2. Focus on world’s “hotspots” More study needed 1. How large does a protected preserve have to be? 2. How much fragmentation can an ecosystem tolerate?

Legal Protections US Laws 1973 Endangered Species Act Established list of threatened and endangered species Protects any endangered species from human harm – guilty parties are fined Prevents the govt. from carrying out any project that threatens an endangered species Establish recovery plans

Legal Protections Recovery and Habitat Conservation Plans Under the Endangered Species Act, a recovery plan must be prepared for each species Controversial-usually compromises between human interests and species interests are made Real-estate developers may be prohibited from building on a desired site that is habitat for an endangered species=loss of income and jobs Habitat conservation plan – attempts to protect one or more species across large areas of land through trade-offs or cooperative agreements

International Cooperation 1. International Union for the Conservation of Nature and Natural Resources (IUCN): facilitates global efforts 2. International Trade and Poaching – CITES Treaty – placed ban on trade of ivory stopping the slaughter of African elephants (began in the 1970’s) successful 3. The Biodiversity Treaty – Created in Earth Summit (held in 1992 in Rio de Janeiro, Brazil) Preserve biodiversity and ensure the sustainable and fair use of genetic resources in all countries Some political groups object to due to impact on trade agreements

International Cooperation 4. Private Conservation Efforts – World Wildlife Fund: http://worldwildlife.org/ Nature Conservancy: www.nature.org/ Conservation International: www.conservation.org/ Greenpeace: www.greenpeace.org/

Balancing Human Needs Humans sometimes are not concerned with the conservation of certain species because: Sometimes endangered species are a food source or source of income Species may not be valued or understood Development of land for human use or economic use overrides the preservation of habitats