Biodiversity

Biodiversity Biological diversity or “Biodiversity” = the sum total of the genetically based variety of all organisms in the biosphere Our existence relies on a great variety of other organisms. Some branches within biodiversity: Ecosystem diversity = variety of habitats, communities, and ecological processes in the ecosystem Species diversity = number of different species in the system Genetic diversity = sum total of all the different forms of genetic information carried by all organisms present

Species Diversity Insects Protists Other Animals Plants Bacteria Fungi Section 6-3 Insects 54.4% Protists Other Animals 4.2% 19.7% Plants 18% Bacteria Fungi 0.3% 3.4% Go to Section:

Value of Biodiversity Biodiversity is one of Earth’s greatest natural resources providing us with food, industrial products, and medicines (painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs) When biodiversity is lost, potential sources of material with significant value to the biosphere and to humankind may be lost. Think of biodiversity as a library- lost species are essentially lost books that can’t be replaced.

Threats to Biodiversity Human activities can reduce biodiversity by: Habitat alteration Hunting species to extinction Extinction = occurs when a species disappears from all or part of its range Endangered species = species in danger of extinction with declining population sizes As the population declines, the species loses genetic diversity, making it more vulnerable to extinction Introducing toxic compounds (pollutants) into food webs Introducing foreign species to new environments

Habitat Alteration & Fragmentation When land is developed, natural habitats may be destroyed and the species that live in those habitats may vanish Habitat fragmentation = development of land that splits ecosystems into pieces resulting in biological “islands” with fewer species and smaller populations more vulnerable to further disturbances or climate changes Reduces habitat space Restricts movement Reduces diversity

Fragmentation

Hunting/Wildlife Products In the past, hunting for meat, fur, hides or other body parts caused the extinction of some species Today, endangered species are protected from hunting by laws in most of the world Endangered Species- species in danger of going extinct. Protected by international and local laws Poaching is still a major problem Bear gall bladders, ivory, shark fins, tiger bones, etc.

Pollution Pollution can threaten biodiversity, because toxic compounds accumulate in tissue of organisms Toxic wastes, sedimentation, thermal pollution Biological magnification = increasing concentrations of harmful substances in organisms at higher trophic levels in a food chain/web Entire food web is affected, but top-level carnivores are at highest risk

Biological Magnification of DDT Section 6-3 Magnification of DDT Concentration Fish-Eating Birds 10,000,000 Large Fish 1,000,000 100,000 Small Fish 10,000 Zooplankton 1000 Producers Water 1 Go to Section:

Thermal Pollution Thermal pollution: is the degradation of water quality by any process that changes ambient water temperature Power plants and industry using local water supplies to cool during manufacturing. The temperature of the discharge water is significantly warmer than normal Warmer water holds less Oxygen, supports less life

Introducing Foreign Species Biodiversity is also threatened by apparently harmless plants and animals that humans transport around the world either accidentally or intentionally Invasive species = organisms introduced into new habitats and reproduce rapidly (think exponential) lacking the parasites and predators that control population size in their native country They can displace native species driving them close to extinction Ex. Zebra Mussels

Invasive species Non-native species kudzu reduce diversity in ecosystem examples African honeybee (killer bees) gypsy moth zebra mussel purple loosestrife Phragmites gypsy moth phragmites kudzu

Purple loosestrife reduces diversity 1968 1978 reduces diversity loss of food & nesting sites for animals

Zebra mussel reduces diversity ~2 months ecological & economic damage reduces diversity loss of food & nesting sites for animals economic damage

Brown Tree Snakes, Guam This introduced snake has caused the extinction on Guam of 12 of 14 forest bird species, two of three bat species, and at least six lizard species. Grow up to 8-10 feet long. Hatch at 15 inches can grow to 3 feet in one year

Guam Bird Populations

Conserving Biodiversity Conservation = wise management of natural resources Preservation of habitats and wildlife to protect Earth’s biodiversity for future generations, however protected areas may not be enough Current conservation efforts focus on protecting individual species as well as entire ecosystems (to ensure natural habitats and interactions among different species are preserved). “Hot spots” = places around the world where everything possible is being done to conserve the ecosystem and species

World Wide Hotspots