Biodiversity biological diversity variety and variability of species

Biodiversity (biological diversity) -variety and variability of species, genes and ecosystems.

Species Diversity 9 million species have been classified Estimates are as high as 100 million “Species Scape” from E O Wilson. Relative number of diversity of major taxa

Species interactions, habitats, niches Diverse physical habitats, moderate disturbances, variations in temperature and precipitation, and many trophic interactions will increase biodiversity Niche - functional position in ecosystem Habitat – place or type of places where a species can live.

Symbiotic Relationships Competition: competition for same resources Competitive exclusion principle: 2 species with same requirements cannot coexist in exactly the same habitat; they will assume different niches. Symbiosis: living together 1. Mutualism - relationship beneficial to both - very common. 2. Commensalism- one species benefits from another without harming or helping it. 3. Parasitism benefits parasite, detrimental to host Predators kill and eat live prey

Values of Biodiversity 1. Variety of food sources for humans and other consumers. 2. Genetic Diversity/Health: Populations are kept in check by predator/prey relationship, lower disease rates. 1. Clean air, reduces flooding and erosion, healthy soil. 1. Resilience: many species provide greater guarantees that some will maintain functioning even if others fail; more resilient to disturbances. 5. Aesthetics-enjoying nature’s beauty

Ecosystem services Air purification Habitat Production for food webs Pollination Decomposition Biogeochemical cycling (C, N, H, O, P, S) Preservation of water and soil quality Population controls ( predators and competitors)

Threats to biodiversity The biggest threats to biodiversity: remember “HIPPO” Habitat loss- habitat destruction and fragmentation Invasive species- introduced species Pollution- degradation of habitat poison Population growth- Human population Over harvesting- overexploitation, over hunting/fishing

Habitat Fragmentation

Habitat Fragmentation

Invasive Species Exotic species - non-native, introduced (Stink Bugs, Kudzu) invasive species can outcompete native species. They are harmful to human health, environment, and/or economy

Definitions Endangered: species in immediate danger of extinction; giant panda, northern spotted owl, whooping crane, green pitcher plant

Threatened: experiencing a population decline, at risk of becoming endangered; African elephant, eastern indigo snake, green sea turtle Recovered species: have rebounded from the threat of extinction; includes brown pelican, bald eagle, peregrine falcon Eastern Indigo Snake

Extinction is a natural process 99% of all species that have ever lived are extinct. The fossil record shows 5 mass extinctions, followed by rapid radiations The average species lasts about 10 million years Extinction rate predicted by the species-area model, about 1 species/year Are current rates much higher? ? ? Are we in the “ 6 th Extinction? ”

Non-Human Causes Previous mass extinctions: asteroids, climate change, volcanic eruptions Natural catastrophes such as fires, floods, volcanoes, hurricanes Chance, especially for rare species or species with low genetic diversity, like Cheetahs

Human Causes THE MAJOR CAUSE: habitat destruction and fragmentation Introduction of exotic species: predators, parasites, competitors Pollution: pesticides, toxic chemicals, biomagnification Overhunting or overfishing, commercial sale of parts, pest control

Common Traits of Endangered species low reproductive rates, long lived, long generation time (kstrategists) large body size (blue whale, lion, elephant, rhino, bison) large home range (tigers) top of food chain (because of biomagnification) specialists in diet or habitat (Panda-bamboo)

Why save species? Ecological: species are essential to ecosystem function Utilitarian: useful to humans (crops, medicines, ecotourism, research) Aesthetic: beauty of nature, cultural value Moral: all species have a right to exist

How do we save species? Protect habitat, establish refuges, sanctuaries, make large preserves Control introduction of exotic species Zoos, aquariums, botanical gardens as temporary refuge Captive breeding programs, gene banks