Presentation on theme: "Can – or should we – prevent extinctions?. Unknown Number of Species on Earth 1.7 million are documented – mostly insects (about 1,000,000) and plants."— Presentation transcript:
Unknown Number of Species on Earth 1.7 million are documented – mostly insects (about 1,000,000) and plants (250,000) 10 million are estimated – many in wildernesses, deep ocean, and in cities SPECIES DIVERSITY – Number of different species in an area. ECOSYSTEM DIVERSITY – The variety of habitats, communities, and ecological processes within and between ecosystems. GENETIC DIVERSITY – All the different genes within all members of a population (same species)
Benefits of Biodiversity 1. Humans use and benefit from the variety of life-forms on Earth. 2.Balanced cycles of energy and nutrients depend upon species that are part of the cycles. 3.When a species disappears from an ecosystem, a strand of the food web is removed. We often do not know the consequences until it is too late! 4.KEYSTONE SPECIES – a species that is critical to the functioning of an ecosystem (eg. Sea otter) When otters disappeared from Pacific coast, sea urchins multiplied and ate most of the kelp. When otters were re- introduced, kelp soon re-grew.
Genetic diversity within populations is critical to species survival. Diversity increases the chance that some members of a population will survive environmental changes. Small, isolated populations are less likely to survive changes. About 25% of all drugs prescribed in the U. S. are derived from plants. Almost all antibiotics come from chemicals found in fungi. Undiscovered – and understudied – plants may hold cures for many human diseases. Neostigmine – calabar bean – treats glaucoma Vincristine – rosy periwinkle – treats pediatric leukemia Bromelain – pineapple – treats tissue inflammation Taxol – Pacific yew – treats cancer Novacaine – coca plant – anesthetic Cortisone – wild yam – anti- inflammatory Reserpine – Indian snakeroot – treats high blood pressure
HUMANS BENEFIT FROM BIODIVERSITY AT EVERY MEAL! We eat fruits, vegetables, and meats from around the world – literally. Some vegetables that originally came from North, Central, or South America are: corn, tomato, beans, peanuts, potato, sweet potato, avocado, pumpkin, pineapple, cocoa, vanilla, and many peppers. Some foods originally from Africa, Central Asia, and the Near East: wheat, sesame, chickpea, fig, lentil, carrot, peas, okra, date, walnuts, coffee, cows, goats, pigs, and sheep From India, East Asia, and the Pacific Islands: soybeans, rice, banana, coconut, lemon, lime, orange, cucumber, eggplant, turnips, tea, black pepper, and chicken HYBRIDS are crops developed by combining genetic material from more than one population. These reduce the probability that a crop will be killed by disease.
Reasons for Preserving Biodiversity ETHICAL: Some believe species and ecosystems have a right to exist whether or not they have any other value. AESTHETICS: Others believe biodiversity provides beauty for personal enjoyment. RECREATION: Ecotourism is an important economy that supports the conservation and sustainable development of ecologically unique areas.
Biodiversity at Risk Mass extinctions have occurred 5 times in the last 500 million years – mostly from global climate change. From 1800 to 2100, about 25 percent of all species on Earth may become extinct. Humans are the primary cause of the extinctions. Species prone to extinction: small populations in limited areas, especially those that migrate, need large or special habitats, and those that are exploited by humans. An Endangered Species: likely to become extinct if protective measures are not taken immediately. A Threatened Species: population is declining and is likely to become endangered if it is not protected. An Exotic Species: Non-native species collected from the wild (often illegally) and used as pets or décor.
HUMANS AS CAUSE OF EXTINCTIONS As human population growth rate increases, so does the number of species extinctions. Causes of extinctions: Habitat destruction (75% of all extinctions) example – the Florida panther; Introduction of non-native species; Pollution; and Over-harvesting of species Non-native (exotic) species threaten native species that have no natural defenses against the invaders. (example: fire ants) Excessive harvesting (legally or illegally) causes many extinctions. (eg. passenger pigeons, bison, orange roughy) Pollution from pesticides, drugs, cleaners and other chemicals used by humans (eg. The bald eagle and DDT)
Areas of Critical Biodiversity Tropical Rain Forests – only 7% of Earth’s land – but contain over half of the world’s species. Coral Reefs – Occupy a small portion of oceans, but contain most of the biodiversity. Provide food, tourism revenue, protect coasts, sources of useful new chemicals. 60% are threatened by pollution and overfishing. Islands - Rise from the sea and are colonized by small numbers of species from the mainland. New species evolve, and are usually endemic (only found in that limited area) to the new island.
Gold Rush in the Rain Forests! Biologists are eager to work in rain forests because of the possibility of: 1) Discovering a new species that he might name 2) Adventure – like charting a new land 3) Economic gain – genetic material may be found that is useful in medicine and research. The Brazilian government has noticed all the interest in species around the Amazon – and now taxes or patents any genetic material harvested there. Natives to the area have vast knowledge of the rain forest – and share their knowledge of uses for plants, fungi, and animals.
BIODIVERSITY HOTSPOTS 25 areas recognized by environmentalists for their high numbers of endemic species that are threatened by humans. Most areas are tropical rainforests, coastal area, or islands. Hotspots in the U. S.: coastal California, Hawaii, the Everglades, midwestern prairie, and Pacific Northwest.
SECTION 3: The Future of Biodiversity Methods being used to save species and protect ecosystems: 1)CAPTIVE-BREEDING PROGRAMS (Calif. Condor) 2)PRESERVING GENETIC MATERIAL (Germ plasm banks store genetic material for future study) 3) ZOOS, AQUARIUMS, PARKS, and GARDENS 4) PROTECTING HABITATS OR ECOSYSTEMS OF ENDANGERED OR THREATENED SPECIES (shade-grown coffee) 5) LEGAL PROTECTION for SPECIES (U. S. Endangered Species Act of 1973 forbids harm, sale or purchase of any part of those species; forbids gov’t projects that jeopardize protected species)
6) Species Recovery Plans; Habitat Conservation Plans may be controversial when people cannot use their own land as they wish. (spotted owl in Pacific Northwest) 7) International Cooperation – IUCN and CITES and Biodiversity Treaties (ivory) 8) Private Conservation Efforts – often are more effective than governmental agencies. World Wildlife Fund, Natur e Conservancy, Conservation International, Greenpeace) (demonstrations, fund-raisers, lobbyists) Conflict arises when human interests (food or income) are counterpoint to preservation of biodiversity. Conservationists often see their most important role as education.