Biodiversity General information Importance of biodiversity Threats to biodiversity Preserving biodiversity

General information Biodiversity refers to the variety of species in a specific area- measured by the number of species in an area Biodiversity varies from place to place on Earth ▫ biodiversity increases from the poles to the equator ▫ more stable conditions allow more specialization, and thus more species

General information A recent study (Aug 2011) estimated that Earth had 7.4 to 10.0 million species 80% of species are animals, 20% plants, fungi, protozoa 86% of land species and 91% of ocean species have yet to be discovered

Importance of biodiversity Biodiversity provides stability to ecosystems

Importance of biodiversity A single species can be critical to an ecosystem ▫ A “keystone” species Pacific coast sea otters ▫ Lived in kelp beds, eating shellfish and sea urchins ▫ Hunted throughout the 1800s for fur ▫ Reduction in sea otters allowed sea urchins to multiply, eating kelp anchors, destroying habitat. In 1937, surviving otters were discovered, with protection their population rebounded, sea urchin population was reduced, kelp beds re-established – otters-urchins-and-kelp/ otters-urchins-and-kelp/

Importance of biodiversity Biodiversity provides resources for future Nearly 40% of prescription drugs originated with living things – mainly from plants ▫ Vinblastine – rosy periwinkle – leukemia ▫ L-dopa – velvet bean – Parkinson’s disease Future foods may come from unknown plants ▫ World relies on three crops – corn, wheat, rice ▫ Vulnerable to diseases/pests – Ireland’s potato crop affected by fungus in 1840s, 2 million died

Threats to biodiversity The most common reason for decline in biodiversity (for accelerated extinction) is habitat destruction as humans use more land

Threats to biodiversity Habitat fragmentation – breaking up large habitat areas into smaller areas –also disrupts ecosystems, reducing biodiversity

Threats to biodiversity Biodiversity can also be threatened by habitat degradation (damage to a habitat by pollution) Air pollution can contribute to acid precipitation Water pollution from excess nutrients can cause algal blooms and subsequent loss of dissolved oxygen Land pollution from pesticides and other chemicals can disrupt food webs

Threats to biodiversity Exotic species – species introduced to areas in which they are not native Lacking natural predators, exotic species out- compete native ones Silver carp Snake head fish Kudzu

Preserving biodiversity The Endangered Species Act ▫ Endangered species – a species whose population is so low that extinction is possible if not protected ▫ Threatened species – a species that could become endangered if not protected Preservation of habitat has been found to be the best approach to protecting endangered and threatened species Conflict between human and wildlife needs can occur and are often very controversial

Preserving biodiversity Captive-breeding programs ▫ Some animals have responded to programs that breed them in zoos and wild- animal parks ▫ Best example – the California condor Botanical gardens and seed banks ▫ Plants, which are not affected by “captivity”, are easily preserved in gardens and seed banks Biodiversity “hotspots” ▫ Areas with unusually large numbers of species ▫ Recommended as focus of ecosystem conservation