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16 Cards in this Set

  • Front
  • Back
About what percentage of species known to science are extinct.
About what percentage of the world's biodiversity may be lost by the middle of the century?
Scientists estimate that no more than _____ percent of the world's eukaryotic organisms have been discovered.
What are megafauna?
Animals weighing more than 100 pounds.
Where have the majority of historic extinctions occurred?
What does it mean for a species to be endemic?
It is found naturally in one area and no place else.
What are hotspots?
Areas of high endemism. They seem to be disappearing at a rapid rate.
What are the three principle values of biodiversity?
1. Direct Economic Value (use plants for stuff), 2. Indirect Economic Value (plants in environment prevent bad stuff), 3. Ethical and Aesthetic Value (living things are pretty).
What was originally the major cause of extinction? What is it now? What ranks second?
Overexploitation. Habitat loss. Introduced species.
Why have declining amphibian populations been a concern for scientists?
1. They have gone extinct even in protected habitats, 2. Amphibians are good gauges of the state of the environment, and 3. No single cause is apparent.
What are the four types of habitat loss caused by humans?
1. Destruction, 2. Pollution, 3. Disruption, and 4. Habitat Fragmentation.
What causes populations' chances of survival to degrade after habitat fragmentation?
Edge effects like changes in microclimate and increased predation.
What two things cause an "extinction vortex"?
Demographic Factors and Lack of Genetic Variablility.
How can endangered environments and species be preserved?
Habitat restoration and captive breeding.
What are the types of habitat restoration?
Pristine (total reconstruction), Removal of Introduced Species, and Cleanup/Rehabilitation.
What are megareserves? How many have been established in Costa Rica?
Large areas of land containing a core of one or more undisturbed habitats. Eight.