Download - Bio 100 Chapter 40
Chapter 40Conservation
BiologyLecture Outline
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40.1 Conservation biology
Conservation biology
Goal of conserving natural resources for this generation and all future generations
Support of biodiversity for all species
Helps reduce extinctions of species
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Biodiversity & Extinction
Biodiversity – variety of life on Earth Between 10 and 50 million species may exist
Of the described species, nearly 1,200 in the United States and 40,000 worldwide are in danger of extinction
Endangered species is in peril of immediate extinction throughout all or most of its range
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Genetic & Ecosystem Diversity
Genetic diversity
Variations among the members of a population
The more diverse a population, the more likely they survive
Ecosystem diversity
Conserve species that play a critical role in an ecosystem
Saving an entire ecosystem can save many species
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Landscape diversity
Landscape diversity Ecosystems can be so fragmented that they are connected by
patches or strips of land that allow organisms to move from one ecosystem to the other
Distribution of Biodiversity Biodiversity is not evenly distributed throughout the biosphere
Some regions of the world are called biodiversity hotspots because they contain unusually large concentrations of species
Exs: Madagascar, Great Barrier Reef in Australia, rainforests
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Medicinal & Agricultural Value
Medicinal Value Most prescription drugs in the United States were
originally derived from living organisms Valued at over $200 billion
Agricultural Value Crops such as wheat, corn, and rice are derived from
wild plants
Biological pest controls (natural predators and parasites) are often preferable to chemical pesticides Ladybugs, bats
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Figure 40.3 Direct value of diverse wildlife (Cont.)
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Consumptive Use Value
Consumptive Use Value Most freshwater and marine harvests depend on the
catching of wild animals, such as crustaceans, mammals, and fishes
Provides a variety of other products that are sold in the marketplace worldwide, including wild fruits and vegetables, skins, fibers, beeswax, and seaweed
Many trees in the natural environment are still felled for their wood
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Ecological Value
Biogeochemical Cycles Dispose of Waste Biodiversity contributes to workings of water, carbon,
phosphorus, and nitrogen cycles
Natural Areas Provide Fresh Water, Prevent Soil Erosion, and Regulate Climate Water-holding capacity of forests and wetlands reduces the
possibility of flooding Forests improve climate because they take up carbon dioxide
Ecotourism Is Enjoyed by Many In U.S., people spend $4 billion each year on ecotourism
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Figure 40.4 Tourists (inset) love to visit natural ecosystems, such as this forest, which has indirect value because of its water-holding
capacity and its ability to take up carbon dioxide
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Habitat Loss & Extinctions
Of 1,880 threatened and endangered species in U.S., habitat loss was involved in 85% of cases
Other significant causes of extinction are introduction of alien species, pollution, overexploitation, and disease
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Figure 40.5A Macaws, Ara macao, and other species are
endangered for the reasons graphed here
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Habitat loss
Alien species
Pollution
Overexploitation
Disease
0 20 40 60 80 100
% Species Affected
© Gunter Ziesler/Peter Arnold/Photolibrary
Non-native Species
Alien species – nonnative members brought into new ecosystems Introduced by
Colonization – Europeans brought various familiar species with them when they colonized new places
Dandelions Horticulture and agriculture – Aliens now taking over vast tracts
of land have escaped from cultivated areas Kudzu is a vine from Japan that the U.S. Department of
Agriculture thought would help prevent soil erosion Accidental transport – Global trade and travel accidentally bring
many new species from one country to another Zebra mussels
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Figure 40.6A Kudzu, a vine from Japan, has displaced many native plants in the southern United States
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40.7 Pollution contributes to extinctions
Exs. of Pollution
Acid deposition – (or “Acid Rain”):Both sulfur dioxide from power plants and nitrogen oxides in automobile exhaust are converted to acids when they combine with water vapor in the atmosphere
Eutrophication – Lakes are also under stress due to over-enrichment (excess nitrogen and phosphorus) Algae blooms occur and upon death, the decomposers break
down the algae, but in so doing, they use up oxygen
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Ozone & Organic Chemicals
Ozone depletion – Ozone (O3) “shield” absorbs most of the wavelengths of harmful ultraviolet (UV) radiation so they do not strike the Earth Severe ozone shield depletion can impair crop and tree growth
and also kill plankton that sustain oceanic life
Organic chemicals – Organic chemicals are used in pesticides, dishwashing detergents, cosmetics & plastics Mimic the effects of hormones and, in that way, most likely harm
wildlife
Solid waste disposal – plastic floating in the ocean creates a danger to wildlife
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http://www.youtube.com/watch?v=tnUjTHB1lvM http://www.youtube.com/watch?v=J-gqJAsXiKQ
Figure 40.7 (Top) Normal coral reef. (Bottom) Bleaching of a coral reef. A temperature rise of only a few degrees causes coral reefs to “bleach” and become lifeless. As the
oceans warm and land recedes, coral reefs could move northward
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40.8 Overexploitation contributes to extinctions
Overexploitation occurs when the number of individuals taken from a wild population is so great that the population becomes severely reduced in number Overexploitation accounts for 17% of extinctions
U.N. Food and Agricultural Organization tells us that humans have now overexploited 11 of 15 major oceanic fishing areas
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40.9 Disease contributes to extinctions
Number of pathogens that cause diseases is on the rise, threatening human health as well as that of wildlife
Pollution can weaken organisms so that they are more susceptible to disease
Example: Almost half of sea otter deaths along the coast of California are now due to infectious diseases
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Figure 40.9The Harlequin toad is near extinction due to a fungal pathogen
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40.10 Habitat preservation: Keystone Species
Keystone species Species that influence the viability of a community,
although their numbers may not be excessively high
Extinction of a keystone species can lead to other extinctions and loss of biodiversity
Ex: Grizzly bears in northwestern US and Canada Berry seed distribution, control populations of other animals
Otters Keep populations of other species in check
Bats Essential pollinators 40-26
Figure 40.10A Landscape preservation will help grizzly bears, Ursus arctos horribilis, survive
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40.11 Restoration Ecology
Restoration ecology – seeks scientific ways to return ecosystems to former state
Three principles have so far emerged It is best to begin as soon as possible before remaining
fragments of the original habitat are lost Once the natural history is understood, it is best to use
biological techniques that mimic natural processes to bring about restoration
Goal is sustainable development, ability of an ecosystem to maintain itself while providing services to human beings
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The Everglades – southern Florida Vast sawgrass prairie, interrupted occasionally by a
hardwood tree island Beginning of 20th century, settlers began to drain land
to grow crops A restoration plan has been developed that will
sustain the Everglades ecosystem, while maintaining the services society requires
The Everglades is to receive a more natural flow of water from Lake Okeechobee
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Figure 40.11 A variety of
animals make their home in the Everglades
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Figure 40.12 These activities are characteristic of a sustainable society. Arrows point inward to signify that these activities increase the carrying capacity of the Earth
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
multi-use farming integrated pestmanagement
conservationof water
mass transit andenergy-efficienttransportation
recycling andcomposting
wetland, deltapreservation
and restoration
(farming): © Inga Spence/Visuals Unlimited; (wetland preservation):© Peter DeJong/AP Images; (recycling): © Jeffrey Greenberg/PhotResearchers, Inc.;(bus): Courtesy DaimlerChrysler; (drip irrigation): ©Inga Spence/Visuals Unlimited; (integrated pest management): Courtesy V.Jane Windsor, Division of Plant Industry, Florida Department of Agriculture &Consumer Services
40.13 Renewable Energy Sources
Traditional renewable energy sources Hydroelectric plants Geothermal energy Wind power Solar energy
In the future, biofuels may run power plants or your car
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Figure 40.13A Traditional sources of renewable energyCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Hydropower dams Wind power
Solar panels on roof-top Sun-tracking mirrors of a solarenergy plant
(dam): © David L. Pearson/Visuals Unlimited;(wind power): © S.K. Patrick/Visuals Unlimited; (solar panels, roof): © Argus Foto Archiv/Peter Arnold/Photolibrary; (solar energyplant): © Gerald and Buff Corsi/Visuals Unlimited
Connecting the Concepts:Chapter 40
Biodiversity includes genetic, ecosystem & landscape diversity
Organisms have medicinal, agricultural & ecological value Habitat loss & introduction of non-native species are
destructive Overexploitation, pollution & diseases contribute to
extinctions Importance of developing renewable energy sources Habitat preservation & restoration = sustainable
development
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