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82 Cards in this Set
- Front
- Back
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How much of the earth's landscape has been completely altered, disturbed, or degraded by human activity?
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50%, or 83% excluding Antarctica and Greenland.
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Why has so much of the earth's landscape been altered by human activity?
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Due to filling in wetlands and creating crop fields and urban areas.
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What percentage of virgin forests (in the lower 48 states) have been logged?
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95% of virgin forests [in lower 48 states] have been logged.
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What percentage of the tall-grass prairies in the Midwest has disappeared?
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98% of tall-grass prairie in the Midwest have disappeared.
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What is one of the most important global issues?
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Maintaining biodiversity if one of the most important global issues.
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What two types of instrumental value does biodiversity have?
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Use value (economical goods and services).
Nonuse value. |
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What are three types of nonuse value?
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Existence value.
Aesthetic value. Bequest value. |
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What is existence value?
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Existence value: satisfaction knowing something continues to exist even if you never see it.
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What is aesthetic value?
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Aesthetic value: beauty.
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What is bequest value?
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Bequest value: saving for future generations.
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How does biodiversity help ecosystems?
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Biodiversity helps maintain structure and function of ecosystems.
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Why do we need to save species?
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a) because they provide us with a wide variety of economic goods.
b) because they are the source of our food crops c) because they contain a vast amount of genetic information that has evolved over millions of years d) because they are a source of a large percentage of our medicines e) because they are used in scientific studies throughout the world f) because they provide us with recreation (hunting, birding, fishing, photography) g) they are important for the ecotourism industry h) because all living things have a right to exist (intrinsic value) i) because they provide us with beauty and something to appreciate j) future generations of mankind have a right to appreciate and use them k) because they provide us with ecological services (photosynthesis, pollination) |
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What is the Theory of Island Biogeography?
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The Theory of Island Biogeography states that the larger an ecosystem or habitat is, the greater the biodiversity that it will support. Fragmenting habitats into small pieces reduces biodiversity.
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Describe the extinction event the earth is currently experiencing.
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Presently, the earth is experiencing its sixth great mass extinction event, caused not by volcanoes or asteroids as in the past, but by human activity.
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What are the worldwide percentages of major organism categories under the threat of extinction?
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Plants: 14%.
Fish: 34% of all fish, 51% of freshwater fish. Amphibians: 25% Reptiles: 20% Birds: 12% Mammals: 24% |
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About what percentage of the animal and plant species in the United States are vulnerable to premature extinction?
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About 33% of the animal and plant species in the US are vulnerable to premature extinction.
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How much of the original wetlands in the United States have been destroyed?
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Over 50% of the original wetlands in the US have been destroyed by human activities (91% in California).
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How many species are there on earth?
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There are probably somewhere between 5 to 20 million species on earth with about 1.4 to 1.8 million having been identified.
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What are the major causes of species extinction?
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a) habitat destruction or degradation
b) introduction of non-native, invasive species into ecosystems c) climate change - global warming d) illegal hunting, poaching, and collecting e) air, soil, and water pollution |
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What is the primary cause of extinction?
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Habitat destruction or degradation.
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What is the second leading cause of extinction?
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Introduction of non-native, invasive species into ecosystems.
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On what three levels can extinction take place?
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a) local extinction.
b) ecological extinction. c) biological extinction. |
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Describe local extinction.
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Local extinction - a species is extinct in a specific area but not worldwide.
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Describe ecological extinction.
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Ecological extinction - a species numbers have been reduced to the extent that it no longer plays a significant ecological role.
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Describe biological extinction.
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Biological extinction - all members of the species are gone worldwide.
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What is the estimated present worldwide extinction rate?
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Scientists estimate that the present worldwide extinction ranges between 1,000 to 75,000 species per year (3 to 200 species per day worldwide).
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According to the scarcity of its individual members, how can species be classified?
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Into the following five categories: common, rare, threatened, endangered, extinct.
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How much of the earth's total land area has been protected from development?
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5.9% of the earth's total land area has been protected from development.
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How much of the earth's tropical rainforests have been destroyed?
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50% of the earth's tropical rainforests have been destroyed; 15 to 20 million hectares per year continue to be lost.
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What are characteristics that make a species vulnerable to extinction?
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a) low production rates..
b) found only in one area, not widespread. c) specialized feeding habits (eats only one or two types of food). d) specialized breeding and reproduction areas. e) high trophic level feeders - animals at the top of the food chain. f) animals or plants that have a specialized niche. g) low population density which reduces mating activity. h) species that interfere with human activity. i) large size which can make a species a more visible target or more commercially valuable. |
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What actions can be taken to save species?
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a) save habitat by establishing or enlarging parks, wildlife preserves, and wilderness areas.
b) regulate privately owned land. c) pass laws to protect species. d) reduce human population growth and consumption. e) restore damaged habitats and reforest damaged forest areas. f) establish captive breeding programs and seed banks. g) educate the public on how to care for and protect the environment. h) reduce and control pollution. i) reduce the effects of global warming and ozone depletion. j) prevent the establishment of non-native, invasive species into ecosystems. |
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What are four important pieces of legislation that help to protect species?
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a) Endangered Species Act (1973)
b) C.I.T.E.S. Treaty (1975) c) Lacey Act (1900) d) Wilderness Act (1964) |
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Describe the Endangered Species Act.
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Endangered Species Act (1973) - protects species in danger of becoming extinct.
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Describe the C.I.T.E.S. Treaty.
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C.I.T.E.S. Treaty (1975) International treaty that protects species throughout the world.
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Describe the Lacey Act.
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Lacey Act (1900) - prohibits transporting wild animals across state boundaries.
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What are the three most biologically productive and species rich areas on earth?
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The three most biologically productive and species rich areas on earth are the tropical rainforests, wetlands, and coral reefs.
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What percentage of all species are found in tropical rain forests?
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It is estimated that at least 40% of all species are found within the tropical rain forests.
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Why is it important that private land owners work with conservationists to save species and habitat?
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It is important that private land owners work with conservationists to save species and habitat because over 55% of the land in the U.S. is privately owned.
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Name some notable endangered species.
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Notable endangered species include: the California Condor, both Elephant species, Cheetahs, Indian Tiger, Black Rhino, Panda Bear, Mountain Gorilla, Desert Tortoise, Florida Manatee, Spotted Owl, Florida Panther, all Sea Turtles, and the Blue Whale.
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Name three types of forests.
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1. Old-Growth.
2. Second-Growth. 3. Tree plantation/Tree farm. |
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What are the types of forests based on?
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Based on age and structure.
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Describe an old-growth forest.
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Old-Growth: uncut or undisturbed for several hundred years.
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Describe a second-growth forest.
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Second-Growth: a stand of trees resulting from secondary succession (due to clear-cutting, crop land, or natural disaster).
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Describe a tree plantation/tree farm.
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Tree plantation/tree farm: a managed tract with uniformly aged trees of 1 or 2 genetically uniform species that are harvested when they become valuable ~ 30 years.
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In the world, what percentage of the forests are old-growth?
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22% are old-growth.
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In the world, what percentage of the forests are secondary-growth?
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63% are secondary-growth.
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In the world, what percentage of the forests are tree plantations?
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5% are tree plantations.
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Where are the old-growth forests?
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5 countries have 3/4 of all old-growth forest.
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Where are the tree plantations?
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5 countries have 2/3 of all tree plantations (U.S.).
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How much of earth's land is covered by forests?
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Forests currently cover 30% of earth's land.
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By how much have human activities reduced earth's original forest cover?
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Human activities have reduced earth's original forest cover by 50%.
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If deforestation rates continue, what will happen?
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If deforestation rates continue, 40% of remaining intact forest will be logged or converted within 20 years.
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What are the deforestation rates?
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0.2%-0.5%.
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What is most timber used for?
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Most timber is used for fuel (developing countries).
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What is the first step to harvesting trees?
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Step 1: Building Roads.
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What are some of the effects of building roads into forests?
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Building roads - increase erosion, sediment runoff, habitat fragmentation, and biodiversity loss.
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What are the three methods to harvesting trees?
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1. Selective cutting.
2. Clear-cut. 3. Strip-cutting. |
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Describe selective cutting.
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Selective cutting: mature trees cut singly or in small groups.
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What are some of the effects of selective cutting?
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Reduces crowding, removes diseased trees, maintains a stand of different species, and multipurpose forest.
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Describe clear-cutting.
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Clear-cut: all trees cut.
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Describe strip-cutting.
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Strip-cutting: more sustainable timber yield without widespread destruction. Cut strips along contours of landscape.
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*Every year more wood is grown in the US that cut.
*More old-growth and diverse secondary-growth cut. Explain how this takes place... |
While old-growth and diverse secondary-growth forests are cut down, more and more tree plantations are established and grown.
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What are the two types of forest fires?
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Surface fires.
Crown fires. |
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Describe surface fires.
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Surface fires: burns undergrowth.
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What are some effects of surface fires?
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Releases nutrients, stimulation germination, and reduces insects.
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Describe crown fires.
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Crown fires: extremely hot, burn everything.
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What are some of the sides of the controversy issue on the management of forest fires?
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-Smoky the Bear (fires bad).
-Surface fires reduce fuel. Slash - logging debris. -Prescribed fires. -Thinning forests around property. |
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What is the Healthy Forests Restoration Act?
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Healthy Forests Restoration Act (2003): TImber companies can cut 71% of national forests as long as they remove underbrush (may increase crown fires).
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What are some benefits of grasslands?
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Grasslands → soil formation, erosion control, nutrient cycling, carbon storing (atm), genetic diversity, provide habitat.
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Describe rangeland.
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Rangeland: unfenced grassland used for grazing (grass) and browsing (shrubs).
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How much of the world's grassland is used by humans?
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45% of the world's grassland used by humans.
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Describe pastures.
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Pastures: managed grassland/enclosed.
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Describe overgrazing.
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Overgrazing: animals exceed carrying capacity = degradation.
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What is a possible effect of undergrazing?
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Undergrazing: decreases NPP.
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What are some examples of managing used with grazing and grasslands?
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Managing - rotational grazing, riparian zones, etc.
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How much of the earth's land area is protected within nature reserves?
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12% (5% strictly) of earth's land area is protected.
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How much of the earth's land area needs to be protected in order to maintain biodiversity?
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20% needed to maintain biodiversity (Nature COnservancy).
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Describe some of the effects of establishing large reserves.
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Large = greater diversity, less fringe area, prone to large disturbances.
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Describe some of the effects of establishing medium reserves.
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Medium (+ habitat corridors) = greater variety of ecosystems, allow migration.
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What are two benefits of establishing nature preserves?
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1. Prevention of loss of biodiversity by identifying and pressserving "hot spots".
2. Sustain local biodiversity while providing local income. |
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Describe "hot spots".
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2% of land contains 52% of plants and 36% of vertebrates.
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Define wilderness.
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Wilderness: undeveloped land.
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