21. climate refers to the average conditions of which two abiotic factors over long periods of time?
a. latitude and longitude
b. greenhouse gases and sunlight
c. temperature and precipitation
d. greenhouse gases and temperature
carefully observe the image below:
22. the glass of a greenhouse allows light to enter but traps heat. which of the following functions
similarly to the glass of a greenhouse?
a. the earth’s surface
b. greenhouse gases
c. sunlight
d. outer space
23. plants in some biomes are adapted to low levels of precipitation. in which biome is extremely low
precipitation an abiotic factor?
a. grassland
b. coniferous forest
c. desert
d. tropical forest
24. according to the graph, which biome would be expected when rainfall ranges between 150 cm/year
and 200 cm/year?
a. tropical rain forest
b. grassland
c. tropical seasonal forest
d. savanna
25. according to the graph, which biome
extends across the largest temperature
variation?
a. temperate forest
b. taiga
c. grassland
d. desert

26. what may cause a species to become less genetically diverse?
a. isolation from members of its species
b. low population numbers
c. both a and b
d. none of the above
27. how are species diversity and genetic diversity different?
a. species diversity measures the number of species in the biosphere, while genetic diversity
measures the variety of genes in the biosphere, including genetic variation within species.
b. species diversity is evaluated only in ecosystems, while genetic diversity is evaluated in the
entire biosphere.
c. species diversity measures the number of individuals of a species, while genetic diversity
measures the total variety of species.
d. conservation biology is concerned with species diversity, but not with genetic diversity.
28. complete the sentence: loss of biodiversity
a. strengthens an ecosystem.
b. causes no change in an ecosystem.
c. weakens an ecosystem.
d. increases the variety of species in an ecosystem.
29. four different ecosystems each have the same number of organisms overall, but different numbers of
species. which ecosystem has the greatest chance of being devastated by a disease?
a. ecosystem i
b. ecosystem ii
c. ecosystem iii
d. ecosystem iv
30. which of the following is not a significant threat to biodiversity?
a. habitat fragmentation
b. emissions of pollution into food webs
c. introduction of invasive species
d. all of the above are significant threats to biodiversity
31. when would the size of a population of animals decrease?
a. when the number of births is less than the number of deaths
b. when the number of births is greater than the number of deaths
c. when the number of births is the same as the number of deaths
d. populations of animals are always decreasing.

use figure 1 to answer questions 32 and 33.
32. what is happening to the growth of the population shown at interval 2:
a. initial growth
b. steady state
c. decline
d. exponential growth
33. the dashed line represents
a. the birthrate of this population
b. the migration rate of this population
c. the carrying capacity of this population
d. the extinction rate of this population
34. which of the following is not a direct effect of deforestation?
a. decreased photosynthetic productivity of the ecosystem
b. soil erosion
c. biological magnification
d. habitat destruction
35. human beings are part of earth's ecosystems. thus, human activities can, deliberately or unintentionally,
alter the equilibrium in ecosystems. humans often change ecosystems as a result of population growth,
consumption, and technology. which of the following illustrates a way in which humans modify
ecosystems?
a. cutting down trees to build new buildings and roads
b. overfishing leads to dramatic declines in fish populations
c. factory and automotive emissions causing acid rain
d. all of these