47.E: Conservation Biology and Biodiversity (Exercises)
47.1: The Biodiversity Crisis
Review Questions
With an extinction rate of 100 E/MSY and an estimated 10 million species, how many extinctions are expected to occur in a century?
- 100
- 10, 000
- 100, 000
- 1, 000, 000
- Answer
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C
An adaptive radiation is________.
- a burst of speciation
- a healthy level of UV radiation
- a hypothesized cause of a mass extinction
- evidence of an asteroid impact
- Answer
-
A
The number of currently described species on the planet is about ________.
- 17,000
- 150,000
- 1.5 million
- 10 million
- Answer
-
C
A mass extinction is defined as ________.
- a loss of 95 percent of species
- an asteroid impact
- a boundary between geological periods
- a loss of 50 percent of species
- Answer
-
D
Free Response
Describe the evidence for the cause of the Cretaceous–Paleogene (K–Pg) mass extinction.
- Answer
-
The hypothesized cause of the K–Pg extinction event is an asteroid impact. The first piece of evidence of the impact is a spike in iridium (an element that is rare on Earth, but common in meteors) in the geological layers that mark the K–Pg transition. The second piece of evidence is an impact crater off the Yucatán Peninsula that is the right size and age to have caused the extinction event.
Describe the two methods used to calculate contemporary extinction rates.
- Answer
-
Extinction rates are calculated based on the recorded extinction of species in the past 500 years. Adjustments are made for unobserved extinctions and undiscovered species. The second method is a calculation based on the amount of habitat destruction and species-area curves.
47.2: The Importance of Biodiversity to Human Life
Review Questions
A secondary plant compound might be used for which of the following?
- a new crop variety
- a new drug
- a soil nutrient
- a pest of a crop pest
- Answer
-
B
Pollination is an example of ________.
- a possible source of new drugs
- chemical diversity
- an ecosystem service
- crop pest control
- Answer
-
C
What is an ecosystem service that performs the same function as a pesticide?
- pollination
- secondary plant compounds
- crop diversity
- predators of pests
- Answer
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D
Free Response
Explain how biodiversity loss can impact crop diversity.
- Answer
-
Crop plants are derived from wild plants, and genes from wild relatives are frequently brought into crop varieties by plant breeders to add valued characteristics to the crops. If the wild species are lost, then this genetic variation would no longer be available.
Describe two types of compounds from living things that are used as medications.
- Answer
-
Secondary plant compounds are toxins produced by plants to kill predators trying to eat them; some of these compounds can be used as drugs. Animal toxins such as snake venom can also be used as drugs. (Alternate answer: antibiotics are compounds produced by bacteria and fungi which can be used to kill bacteria.)
47.3: Threats to Biodiversity
Review Questions
Which two extinction risks may be a direct result of the pet trade?
- climate change and exotic species introduction
- habitat loss and overharvesting
- overharvesting and exotic species introduction
- habitat loss and climate change
- Answer
-
C
Exotic species are especially threatening to what kind of ecosystem?
- deserts
- marine ecosystems
- islands
- tropical forests
- Answer
-
C
Free Response
Describe the mechanisms by which human population growth and resource use causes increased extinction rates.
- Answer
-
Human population growth leads to unsustainable resource use, which causes habitat destruction to build new human settlements, create agricultural fields, and so on. Larger human populations have also led to unsustainable fishing and hunting of wild animal populations. Excessive use of fossil fuels also leads to global warming.
Explain what extinction threats a frog living on a mountainside in Costa Rica might face.
- Answer
-
The frog is at risk from global warming shifting its preferred habitat up the mountain. In addition, it will be at risk from exotic species, either as a new predator or through the impact of transmitted diseases such as chytridiomycosis. It is also possible that habitat destruction will threaten the species.
47.4: Preserving Biodiversity
Review Questions
Certain parrot species cannot be brought to the United States to be sold as pets. What is the name of the legislation that makes this illegal?
- Red List
- Migratory Bird Act
- CITES
- Endangered Species Act (ESA)
- Answer
-
C
What was the name of the first international agreement on climate change?
- Red List
- Montreal Protocol
- International Union for the Conservation of Nature (IUCN)
- Kyoto Protocol
- Answer
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D
About what percentage of land on the planet is set aside as a preserve of some type?
- 1 percent
- 6 percent
- 11 percent
- 15 percent
- Answer
-
C
Free Response
Describe two considerations in conservation preserve design.
- Answer
-
Larger preserves will contain more species. Preserves should have a buffer around them to protect species from edge effects. Preserves that are round or square are better than preserves with many thin arms.
Describe what happens to an ecosystem when a keystone species is removed.
- Answer
-
When a keystone species is removed many species will disappear from the ecosystem.