* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Four Blocks - Plain Local Schools
Survey
Document related concepts
Unified neutral theory of biodiversity wikipedia , lookup
Occupancy–abundance relationship wikipedia , lookup
Extinction debt wikipedia , lookup
Conservation biology wikipedia , lookup
Latitudinal gradients in species diversity wikipedia , lookup
Island restoration wikipedia , lookup
Biodiversity wikipedia , lookup
Pharmacognosy wikipedia , lookup
Biodiversity action plan wikipedia , lookup
Transcript
CH. 10 Biodiversity “…in the wilderness is the preservation of the world.” Henry David Thoreau American Writer and Naturalist Biodiversity at Risk • Mass extinctions (extinctions of many species in a short period of time) have occurred over the course of Earth’s history • Most famous is the extinction of the dinosaurs, which happened over 65 million years ago • Many worry that we are currently in another period of mass extinction in Earth’s history • This extinction is being caused directly by human activity • Species are disappearing at a rate 1000 times faster than at any time since the extinction of the dinosaur A World Rich in Biodiversity • Biodiversity – the number and variety of species on Earth • There are about 1.6 million species known to science • Most are insects • It is estimated that there are actually about 13 million different species on Earth altogether • Most have not been discovered yet • Tropical rain forests are the most diverse places on Earth How are Humans Causing Extinctions? • Population Growth • The human population is increasing at a rate of 220,000 a day • As humans take up more and more space and deplete more resources, we destroy the habitats of other species • Unregulated hunting and the introduction of nonnative species are contributing to extinctions Habitat Destruction • Habitat destruction is the leading cause today of species extinction (75%) • Ex: Florida panther, in 1994 only 30-50 remained in the wild; whooping crane • As human populations grow, we need more land to build homes and harvest resources. • Most extinctions are occurring in tropical rain forests Hunting • Unregulated hunting can lead to species extinction, too • Ex: early 1900’s, 2 billion American passenger pigeons were legally hunted to extinction; American buffalo was nearly hunted to extinction in the 1800’s (60 million in the 1800’s, 1906 only 300 remained) • Wildlife laws in the U.S. ensure only a certain number of game animals are killed each year; laws were established to protect certain animals and invoke heavy fines and possible jail time for poachers • In developing countries, poaching (illegal hunting), as a means for survival, still exists and threatens many species ex: African elephants Exotic species • Exotic species are species that are not native to a particular region, brought into an area where they never lived before, and have no natural defenses against them • Ex: Melaleuca tree in South Florida and the Kudzu plant which is invading the South and moving North The Value of Biodiversity • Extinction is a natural process – species appear, flourish for a time and then become extinct; 99% of all the species that have ever lived are now extinct • Protecting species on the verge of extinction is difficult and expensive Saving Species Preserves Ecosystems • Saving species preserves ecosystems • The balance of species keeps the flow of energy regulated and cycles nutrients properly • It’s impossible to accurately predict how the loss of certain species will affect an ecosystem…where is the breaking point? • Keystone species – a species who is so important to an ecosystem that its loss may cause a total collapse; ex: sea otter Practical Uses of Species • Forty (40%) percent of all prescription drugs originate from living species • Medicinal plants have been made to treat childhood leukemia, cancer, Parkinson’s disease • Loss of biodiversity may mean a loss in developing future medicines, finding potential food sources, and discovering naturally found plants resistant to pests and fungus. Ethical and Aesthetic Reasons • Many believe that humans have a responsibility to tend to the Earth’s organisms • People believe that loss of a species means a loss in beauty and wonderment • Time spent among other living things renews our sense of connection with life and our appreciation of the world in which we live 10.2 Public Policy • Biodiversity and public policy • The Endangered Species Act – this law is designed to protect plant and animal species in danger of extinction The Endangered Species Act • The U.S. fish and wildlife service must compile a list of all endangered and threatened species • • - an endangered species is one whose #’s have grown so low that it is likely to become extinct in the future - a threatened species is one that is likely to become endangered if it is not protected • Endangered and threatened animal species my not be caught or killed; plants on federal land may not be uprooted; no part of any endangered or threatened plant or animal my be sold or traded • The Federal government may not carry out any project that jeopardizes endangered species • The U.S. fish and wildlife service must prepare a species recovery plan for each endangered and threatened species • - the most effective way to save a species is through a protection of their habitat Developers vs. Environmentalists • Plans involving restriction of land use are sometimes controversial • From the developers viewpoint: • - may disrupt plans for development of an area • - may cost jobs for community members • - may cost investors a lot of money • From the environmentalists viewpoint: • - no money making venture is worth the extinction of a species • These standoff’s usually end up in court and then eventually in some sort of compromise Worldwide Efforts to Prevent Extinctions • Several international organizations work to protect species: • • • • • • The World Wildlife Fund The Nature Conservancy Conservation International Friends of the Earth Greenpeace International International Union for the Conservation of Nature and Natural Resources • The Convention on International Trade in Endangered Species (CITES) • The Biodiversity Treaty Prevention of Poaching • CITES, in 1989, proposed a total worldwide ban on all sales, imports and exports of ivory; hopes to put a stop to the slaughter of African elephants for their ivory tusks • Sale of ivory was completely banned in 1989; consequently, the poaching of elephants declined dramatically The Biodiversity Treaty • Earth Summit, in 1992, which took place in Rio de Janeiro, Brazil (100 world leaders and 30,000 participants) met to tackle environmental issues; result was the Biodiversity Treaty • Former president Bush did not sign, stating it was too vague; following year, former president Clinton signed it 10.3 The Future of Biodiversity • It is possible to slow the loss of species, but to do so we must develop new approaches to conservation and a sensitivity to human needs around the globe. Saving Individual Species • Legislation such as the Endangered Species Act and anti-poaching laws are attempts to save individual species. • Additional ways to save species are captive-breeding programs, botanical gardens and germ-plasm banks. Captive-Breeding Programs • Used by zoos and wild animal parks • Animals are protected and allowed to mate in captivity • If numbers climb high enough, some are released back into the wild • Ex: California condor Botanical Gardens • Places where rare and exotic plants are grown in order to protect biodiversity • Botanical Gardens house nearly 90,000 different species of plants worldwide • That still is not enough to protect most of the world’s endangered and threatened plants Germ-Plasm Banks • Stores endangered plants and animal genetic information in the form of plant seeds or the frozen sperm and eggs of endangered animals • This genetic information may be used if the plant or animal becomes critically endangered • This genetic information can last for many, many years The Ecosystem Approach • Protects entire ecosystems instead of individual organisms • Two reasons for the ecosystem approach: • - more species are in danger of extinction than can possibly be placed on official lists; so by protecting ecosystems we can save most of the species in an ecosystem instead of just one; we may also be protecting species that we are not even aware of • - preserving ecosystems protects the health of the biosphere • Many believe special consideration should be given to ecological hot spots • - areas with especially high biodiversity What About Human Needs? • We must find ways to meet the human needs and manage living resources at the same time • In poorer nations of the world, the conflict between human needs and biodiversity may even be a matter of life or death • Preserving these resources will most likely be the greatest challenge of the 21st century.