Biodiversity

Its Importance and Its Future

Biodiversity

Biodiversity

• The number and variety of different species in a given area

• Humans need to preserve biodiversity for our own survival

• Extinction of species leads to a decrease in biodiversity

• Humans don’t know which species are key to our survival on Mother earth

Benefits of Biodiversity

• Species and ecosystems are interconnected• Species and populations must survive• Humans are dependent on species for

medical, industrial, and agricultural uses• The are ethical, aesthetic and recreational

reasons to preserve species, ecotourism

Benefits of Biodiversity

• Keystone species: any species that must be present in a ecosystem for that ecosystem to survive

• When a species is removed, a strand of a food web is eliminated

Species versus populations

• In general, in any given area, the more species, the smaller the population

• And the less species, the larger the population• Always remember that an ecosystem is

healthiest when there are the gretest number of species

• When an ecosystem is healthy, it is less likely for any individual species to go extinct

Number of Species on Earth

• About 1.7 million known• Mostly insects• Vertebrates comprise the fewest species

Other types of Diversity

• Ecosystem diversity• Genetic diversity• Genetic diversity is a critical factor to a

species, the less genetically diverse a species, the more likely it is to go extinct

Population Bottleneck

Stop and Answer

• Describe the 3 levels of biodiversity• Explain how biodiversity is important to

ecosystems

Biodiversity at Risk

Mass Extinctions

Current Extinctions

• Between 1800 and 2000 up to 25% of all species may have gone extinct

• Endangered species: likely to become extinct if steps are not taken to preserve it

• Threatened species: has a declining population and is likely to become endangered if it is not protected

Mass Extinction

How do humans cause extinctions

• Habitat destruction and fragmentation– Fragmentation is breaking ecosystems into smaller

and smaller pieces– Example Ashburn

Humans and extinctions

• Introduction of invasive exotic species– An exotic species is not native to a region– An exotic species may become invasive if it has no

natural predators– Examples:• Fire ants• Killer bees• Kudzu• Canadian thistle

Humans and extinction

• Harvesting, hunting, poaching– Poaching is illegal hunting– Excess harvesting and hunting leads to species

decline

Humans and Extiction

• Pollution– Pesticides– Cleaning agents– Drugs

Areas of Critical Biodiversity

• Certain areas of the world contain a greater diversity of species than other areas

• They have a large portion of endemic species, that is species that are native to an area

• Example: in a tropical rain forest there may be 200 tree species in an acre, but in a temperate forest there is usually only about 25 endemic species per acre

Tropical Rain Forests

• Many of the plants in tropical rain forests have antibiotic or anti-cancer properies

• Tropical rainforests are at ever increasing risk as land is cleared for farming and grazing and trees are sold for timber or burned

Coral Reefs and Coastal Ecosystems

• These areas are the nurseries for most of the fish on Mother Earth

• Pollution is greatest along coasts worldwide because most of the big human cities are located along the coast

• Overdevelopment is also causing destruction of dunes and wetlands which protect the coast

• Overfishing is causing fish extinctions worldwide

Biodiversity Hot Spots

• Hot spots are the most threatened areas of high species diversity on Earthmost of the hotspots have lost 70% or more of their natural vegetation

• When the vegetation goes, so do the animals• Mostly tropical rainforests, coastal areas and

islands

Hotspot Losses

• Madagascar more than 80% of its 10,000 flowering plant species and 90% of its reptile species are endemic

• Most live no where else on Earth• All 33 species of lemur are found only in

Madagascar, this is 18% of all primate species on Earth

• Madagascar has lost 18% of its forests

HotSpots

Biodiversity in thUSA

• Contains 3 biodiversity hotspots– Florida Everglades– Hawaii– California coastal region• 3488 native plant species• 2124 are endemic• 565 threatened or endangered

Stop and Answer

• Describe 4 ways that species are threatened with extinction

• Define endangered species and threatened species