In Class Assignment BiomesName:___________________ • ____________ contains widely scattered clumps of trees such as acacia which are covered with thorns, has warm temps year round, and alternating wet and dry seasons • _____________humans have converted much of this biome to farmland because its fertile soil is good for raising crops and grazing cattle • ______________ in this biome very little plant litter reaches the ground, nutrients that do reach the ground are soon leached from soil by constant rainfall, and 90% of plant nutrients released by decomposition are taken up and stored by plants • _______________ contain majority of world’s forests, host many endemic species, key in hydrologic cycle. • Coral is formed by ______________ . They are in a symbiotic relationship with __________________ algae. • ____________________ coastal forests with extensive root systems that often extend above the water. Can be found on some tropical coastlines.
13e ENVIRONMENTALSCIENCE CHAPTER 8:Sustaining Biodiversity: The Species Approach “In the end we will conserve only what we love. We love only what we understand. We will understand only what we are taught.” Baba Dioum
Core Case Study: Polar Bears and Projected Climate Change In Chapter 7 we discussed climate and biomes. What affect do you think climate change will have on arctic biomes? Fig. 8-1, p. 152
Polar bear video • http://www.youtube.com/watch?v=OwZH_aT0FGI&feature=related
Core Case Study: Polar Bears and Projected Climate Change • 20,000 – 25,000 polar bears in Arctic • Hunt seals on winter sea ice • Global warming is quickly reducing the amount of sea ice and how long it lasts in winter • Polar bears have less time to hunt and store fat for summer fasting
Polar Bear Case Study • Projected 30-35% decline of total polar bear population by 2050 • Potentially extinct from wild by 2100
Resource: San Diego Zoo Website • http://www.sandiegozoo.org/polarcam/gallery.html • http://blogs.sandiegozoo.org/category/default/polar-bears/ San Diego Zoo Global is an international conservation organization that has been saving species for over 95 years. Experts in scientifically based breeding, conservation, and reintroduction programs for endangered species.
What do you think • How have human activities affected natural extinction rates? • How are we likely to affect such rates in the next 50-100 years?
8-1 What Role Do Humans Play in the Premature Extinction of Species? • Concept 8-1 Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on earth, and by the end of this century, the extinction rate is expected be 10,000 times higher than the background rate.
Human Activities and Extinction • Background extinction rate- normal extinction of various species as a result of various changes in local environmental conditions • Current rate is 100-1,000 times background extinction • Rate likely to rise to 10,000times • Is a mass extinction coming? • Mass extinction- catastrophic, widespread often global event in which major groups of species are wiped out over a short time compared with normal (background) extinctions
Review of terms • Local extinction- • Biological extinction-
Review of terms • Local extinction- species is no longer found in one area it once inhabited but is found in other areas but is found elsewhere on earth • Biological extinction- species is no longer found anywhere on earth; biological extinction is forever! Irreversible
Current Extinction Rate Estimates Are Conservative • Rate of species loss and biodiversity losses will increase in next 50–100 years • Why? • Biodiversity hotspot rates higher than global average • We are eliminating, degrading, fragmenting and simplifying many biologically diverse environments that would serve as the sites for the emergence of new species
Some animal species that have become prematurely extinct largely because of human activities, mostly habitat destruction and overhunting. Fig. 8-2, p. 154
What are endangered and threatened species? • Endangered species: wild species with so few individual survivors that the species could soon become extinct in all or most of it’s natural range • Threatened species-wild species that is still abundant in its natural range but is likely to become endangered in the near future because of a decline in numbers • Edward O Wilson “The first animal species to go are the big, the slow, the tasty, and those with valuable parts such as tusks and skins” • Some behaviors make species prone to extinction: ex. Passenger pigeon, Key deer
Examples Characteristic Blue whale, giant panda, rhinoceros Low reproductive rate Characteristics of species that are prone to ecological and biological extinction. Critical Thinking Which of these characteristics might contribute to the premature extinction of the polar bear during this century? Blue whale, giant panda, Everglades kite Specialized niche Elephant seal, desert pupfish Narrow distribution Bengal tiger, bald eagle, grizzly bear Feeds at high trophic level Blue whale, whooping crane, sea turtle Fixed migratory patterns African violet, some orchids Rare Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Commercially valuable California condor, grizzly bear, Florida panther Large territories Fig. 8-4, p. 157
Case Study:Passenger Pigeon: Gone Forever • John James Audubon, 1813: took 3 days for a flock to pass over, flock so dense it darkened the skies • Yet by 1900, North America’s Passenger Pigeon, once one of the most abundant birds on earth, was extinct • Good to eat • Feathers good for pillows • Bones good for fertilizer • Easy to kill, flew in flocks and nested in colonies
Passenger Pigeon links • http://mnh.si.edu/onehundredyears/featured_objects/martha2.html • First link has short video clip • http://blogs.smithsonianmag.com/aroundthemall/2011/09/martha-the-worlds-last-passenger-pigeon/
Cincinnati Zoo Memorial to Martha and the Passenger Pigeons Critical Thinking: What difference does it make that the passenger pigeon is extinct?
Considerations • Intrinsic (existence) value: each wild species has inherent right to exist regardless of its usefulnes to us • Stewardship viewpoint: we have an ethical responsibility to protect species from becoming prematurely extinct as a result of human activities and to prevent the degradation of the world’s ecosystems and its overall biodiversity • Instrumental value: species usefulness to us because of the many ecological and economic services they help provide as part of the earth’s natural capital
8-2 Why Should We Care about Preventing Species Extinction? • Concept 8-2 We should prevent the premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.
Value of Species • Instrumental value of BIODIVERSITY • Food crops • Genetic information • Medicine • Bioprospectors • Ecotourism • We do not know what we lose when species go extinct
Critically Endangered • According to the WWF, the 5 most endangered animals in the wild are the Javan rhino (70 left), whooping crane (250 left), mountain gorilla (600 left), Siberian tiger (700 left), and the California condor (336 left) • I was fortunate to learn more about the California condors last year when I went to San Diego and visited the San Diego Zoo and the San Diego Zoo Safari Park (Wild Animal Park)
San Diego Zoo Global International conservation organization that has been saving species for over 95 years Experts in scientifically based breeding, conservation, and reintroduction programs for endangered species
Case Study: Trying to Save the California Condor • Nearly extinct with only 22 condors remaining in the wild • Last 22 individuals captured, bred in captivity • Released a few at a time • 2009: 167 condors in the wild • Greatly threatened by lead poisoning from animal carcasses and gut piles
Condor Population reaches 100 in California The goal of the California Condor Recovery Plan is to establish two geographically separate populations, one in California and the other in Arizona, each with 150 birds and at least 15 breeding pairs. As the Recovery Program works toward this goal the number of release sites has grown. There are three active release sites in California, one in Arizona, and one in Baja, Mexico.
Condor hatching video • http://www.youtube.com/watch?v=XNkV02P8Ysc
San Diego Zoo Condor Cam • http://www.sandiegozooglobal.org/video/condor_cam
Condor video: Condor nest update • http://www.youtube.com/watch?v=nO8Ro94l5C4
Condor References • http://www.sandiegozoo.org/animalbytes/t-condor.html • http://content.usatoday.com/communities/sciencefair/post/2010/10/california-california-condor-population-reaches-100/1?csp=usat.me
Critical Thinking • What are some differences between the stories of the condor and the passenger pigeon that might give the condor a better chance of avoiding premature extinction than the passenger pigeon had?
Little Fish, Big ControversyThe Story of Snail Darter, the Endangered Species Act, TVA, and the Tellico Dam
The Snail Darter Story: Connection to History, Economics, Politics • In August of 1973, a University of Tennessee biologist discovered a small fish species, the snail darter, in the Little Tennessee River while conducting research involving a lawsuit around construction of the Tellico Dam. Creation of the Tellico Reservoir, to be created by the Tellico Dam, the scientist predicted, would alter the snail darter's habitat to the point of extirpation. Opponents of the dam used the snail darter as leverage in attempting to halt construction and invoked the Endangered Species Act to do so. The Tennessee Valley Authority argued that (1) since the Act was passed after the project began (December 1973) it did not apply and (2) after Congress passed the Endangered Species Act it continued to appropriate funds to Tellico; therefore, Congress did not intend for the ESA to apply to Tellico. • The Supreme Court's ruling in Tennessee Valley Authority vs. Hill (1978) was unprecedented. Speaking for the majority, Chief Justice Warren Burger announced the court's decision to rule in favor of the snail darter, halting construction on the Tellico Dam. Caution was taken not to say that Congress broke the law by funding the Dam. According to the ruling, the language and intended goals of the Endangered Species Act are clear: there are no exceptions for project like Tellico that were well under way when Congress passed the Act, and that Congress' intent was to slow, stop and reverse the trend toward species extinction—no matter the cost. • Soon after the ruling, Tennessee legislators in favor of the Tellico Dam began an appeals process which included sponsorship of an amendment to the Act that would form an investigative committee whenever controversy arose over a listing. Dubbed the "God Squad," even this committee deemed the Tellico Dam project “dangerous” to the snail darter and "economically not beneficial." Nonetheless, legislators appealed again, and the case reached President Jimmy Carter's desk in 1979. Although he wanted to veto the bill that would override the Supreme Court's decision, political realities and other pressing issues, like the Panama Canal Treaty, forced the President to sign it on September 25, 1979. As the gates closed on the Tellico Dam and the Tellico Resevoir formed in subsequent years, several other populations of the snail darter were found elsewhere around the country, and the species was delisted in the late 1980s. • The snail darter controversy not only illustrates the conflict between conservation biologists and economic interest groups, it also shows just how entwined science and politics are in conservation legislation. Biologists and politicians alike have suggested ways to mitigate the problems arising from this unhappy marriage, which will be discussed in later sections. • http://www.macalester.edu/environmentalstudies/students/projects/citizenscience2007/endangeredspecies/controversy.html
Homework Snail Darter • What were some of the objections to the Tellico dam project? • Why did the dam project get so far along before the environmentalists called for a halt to it? • What were the arguments for continuing with the project? • What ultimately happened to the snail darter? • What lessons can we learn from this controversy that will help us solve environmental, economic, legal problems in the future?
The Tellico Dam and the Snail DarterConnections to history, politics, and economics • http://www.utc.edu/Faculty/John-Tucker/Courses/esc430/esc430mat/darter/tellico.html • http://bgpappa.hubpages.com/hub/The-Story-Of-The-Snail-Darter
Why should we care if plant species become extinct? Rauvolfia Rosy periwinkle Pacific yew Neem tree Foxglove Cinchona Cathranthus roseus, Madagascar Hodgkin's disease, lymphocytic leukemia Taxus brevifolia, Pacific Northwest Ovarian cancer Rauvolfia sepentina, Southeast Asia Anxiety, high blood pressure Azadirachta indica, India Treatment of many diseases, insecticide, spermicide Digitalis purpurea, Europe Digitalis for heart failure Cinchona ledogeriana, South America Quinine for malaria treatment Nature’s pharmacy. Part’s of these and a number of other plant and animal species (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer fighting chemicals come from tropical forests. Fig. 8-7, p. 158
Zoos and Aquariums for Protection • Collect species with long-term goal of returning them into habitat • Egg pulling • Captive breeding • 100–500 captive individuals to avoid extinction • 10,000 individuals to maintain capacity for biological evolution
8-3 How Do Humans AccelerateSpecies Extinction? • Concept 8-3 The greatest threats to any species are (in order) loss or degradation of its habitat, harmful invasive species, human population growth, pollution, climate change, and overexploitation.
Causes of Endangerment and Premature Extinction (HIPPCO) • Habitat destruction • Invasive species • Population growth • Pollution • Climate change • Overexploitation • know for exam
Review for exam Natural Capital Degradation Causes of Depletion and Premature Extinction of Wild Species Underlying Causes • Population growth • Rising resource use • Undervaluing natural capital • Poverty Direct Causes • Habitat loss • Habitat degradation and fragmentation • Introduction of nonnative species • Pollution • Climate change • Overfishing • Commercial hunting and poaching • Sale of exotic pets and decorative plants • Predator and pest control Fig. 8-8, p. 160
Habitat Loss • Deforestation of tropical areas greatest eliminator of species • Endemic species-species that is found in only one area • Habitat fragmentation- by roads, logging, agriculture, and urban development, occurs when a large, intact area of habitat is reduced in area and divided into smaller, more scattered, and isolated patches, or “habitat islands”
Reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and million of other species when the world’s human population doubles and per capita resource consumption rises sharply in the next few decades? Indian Tiger Black Rhino Range 100 years ago Range in 1700 Range today Range today African Elephant Asian or Indian Elephant Former range Probable range 1600 Range today Range today Stepped Art Fig. 8-9, p. 161
Case Study: Declining BirdSpecies (1) • Decline of ~70% of ~10,000 known species • 12% threatened with extinction • Birds around humans benefited, but forest species declined • Long-distance migrants – greatest decline
Case Study: Declining BirdSpecies (2) • Reasons • Habitat loss • Habitat fragmentation • Climate change • Birds are environmental indicators (species that serve as early warning that a community or ecosystem is being degraded) • Perform economic and ecological services
Species Introductions • Most beneficial – food crops, livestock, pest control • 500,000 alien invader species globally • 50,000 nonnative species in the U.S. • Some definitely not beneficial
Deliberately Introduced Species African honeybee (“Killer bee”) Salt cedar (Tamarisk) Purple loosestrife European starling Nutria Marine toad (Giant toad) European wild boar (Feral pig) Water hyacinth Hydrilla Japanese beetle Fig. 8-10, p. 163
Accidentally Introduced Species Eurasian ruffe Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Common pigeon (Rock dove) Zebra mussel Gypsy moth larvae Formosan termite Asian long-horned beetle Asian tiger mosquito Fig. 8-10, p. 163