Name: _________________________
AP Environmental Science
Biodiversity Loss and Species Extinction
12 December 2013
Chapter 11 – pp 280-296
1. Read the Central Case Study: “Saving the Siberian Tiger.” List TWO factors that have contributed to the
decline in Siberian Tiger populations in the last century. List TWO practices that have helped to increase
tiger numbers and protect the population in recent years.
Factors that contribute to Siberian Tiger
decline
Practices that have increased Siberian Tiger
populations
2. Match the term in Column A with its description in Column B.
Column A
Column B
____ biological diversity
A. The variety of life across all levels of biological organization
____ species diversity
B. Differences in DNA composition among individuals
____ genetic diversity
C. Number or variety of species in a particular region
____ ecosystem diversity
D. Number or variety of ecosystems, communities, or habitats
in a particular area
3. A _____________________ is a distinct set of individual organisms that share certain characteristics and
can breed with one another and produce fertile offspring. _____________________ can arise by the
process of allopatric speciation that stops short of forming separate species.
4. Contrast species richness with species evenness. Which of these do you think matters more to the health of
a biological community?
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5. Why is low genetic diversity in a population of organisms of concern to biologists?
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Assessment Key: Know why measuring biodiversity is difficult.
6. List THREE reasons why estimating the actual number of species on our planet is difficult and remains
incomplete.
i.
_______________________________________________________________________________
ii.
_______________________________________________________________________________
iii.
_______________________________________________________________________________
Assessment Key: Understand the factors that contribute to the apparent latitudinal gradient of species
diversity that exists on the Earth.
_____ 7. The number of species in an ecosystem generally increases as one travels from the poles to the
equator. Which of the following does NOT support this latitudinal gradient in species richness?
A.
B.
C.
D.
E.
Terrestrial plant productivity, which supports food webs, is typically higher in tropical latitudes.
Climates are more stable in tropical latitudes which favor specialist species.
Previous glaciation events repeatedly displaced numerous species from higher latitudes.
Variable climates in temperate biomes favor more tolerant and more competitive generalists.
Habitats that are more structurally diverse or that exist in a patchwork have more ecotones that
favor greater local species diversity.
8. Explain the difference between extinction and extirpation.
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9. Read each statement. Mark it with ‘T’ if the statement is true. Mark it with ‘F‘ if the statement is false.
_____ a. Most extinctions in the past have occurred gradually one by one at a pace scientists call the
background rate of extinction.
_____ b. Mass extinctions are regular occurrences, happening approximately every 1,000 years or so.
_____ c. Scientists estimate that our planet has experienced five major mass extinction events over the past
440 million years.
_____ d. Dinosaurs perished during the most recent mass extinction at the end of the Cretaceous period, 65
million years ago.
_____ e. Many agree that our planet is poised to see the next, or sixth, mass extinction and that it has been
brought about by humans.
Assessment Key: Know the significance of the IUCN Red List and the Living Planet Index.
10. The International Union for Conservation of Nature (IUCN) maintains a ______________________, an
updated list of all species facing high risks of extinction.
11. What is the general trend in the United Nations Environment Programme’s Living Planet Index? Why is
this of concern?
______________________________________________________________________________________
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Assessment Key: Know the FIVE primary causes of population decline and species extinction. Be able to
give examples of each.
12. List the FIVE primary causes of population decline and species extinction. Define each.
i.
_______________________________________________________________________________
ii.
_______________________________________________________________________________
iii.
_______________________________________________________________________________
iv.
_______________________________________________________________________________
v.
_______________________________________________________________________________
13. What is the single greatest cause of biodiversity loss today? ___________________________________
14. Sudden elimination of habitat is uncommon; however, _______________ ______________________ is
far too routine as farming, logging, road building, and development gradually degrade habitats piecemeal.
15. Place the following steps of habitat degradation in order.
_____ a. A few, small isolated fragments of habitat remain; any species that cannot tolerate this patchy
distribution has been eliminated.
_____ b. As development proceeds, developed areas increase in size, gaps between original habitat widen,
and additional species are displaced.
_____ c. A continuous forest is home to a variety of plants and animals.
_____ d. Development and human land use form gaps that fragment the forest into smaller pieces; animals
and plants adapted to unbroken forest will be eliminated.
16. Your text mentions a number of severe and concerning pollution related impacts; however, it also notes
that pollution ‘tends to be less significant than public perception holds it to be.’ Why might this be so?
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17. Why are K-selected species more vulnerable to overharvesting than many other organisms?
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18. List THREE methods being employed to combat overharvesting.
i.
_______________________________________________________________________________
ii.
_______________________________________________________________________________
iii.
_______________________________________________________________________________