22. Darwin's main conclusions about the origin of species were _____.
(A) all organisms are descended with modification from common ancestors
(B) the mechanism for evolution was natural selection
(C) inheritance is generally particulate
(D) A and B
(E) B and C

18. How are species-area relationships traditionally plotted? (A) On a bar graph (B) On a log-log plot (C) On a semi-log plot (D) As a regular graph (E) As a pie chart

19. Which of the following properties of a river is the closest to the headwaters? (A) Channel depth (B) Mean flow velocity (C) Bed material grain size (D) Stream discharge volume (E) Volume of stored alluvium

20. If primary production increases in an ecosystem, it would be reasonable to expect that _____. (A) nutrients are a limiting factor (B) gross production would not increase (C) cellular respiration would decrease (D) the food web has become more complex (E) the biomass of herbivores would increase

21. If a forested area surrounding a stream is cleared of trees, what might happen? (A) Increased import of nutrients to the soil (B) Decreased rates of soil and rock weathering (C) Increased run-off of water (D) Decreased rates of chemical leaching (E) Increased denitrification

23. The Hardy-Weinberg equation states that p2 +2pq + q2 = 1; the genotype frequency of heterozygotes is represented by _____. (A) p2 (B) 2pq (C) q2 (D) p2 + q2 (E) p2 + 2pq

24. Populations are best defined as _____. (A) all members of a species (B) all organisms found in an environment (C) families (D) metacommunities (E) groups of interbreeding individuals

25. Which is NOT a feature of habitat destruction? (A) swamp drainage (B) deforestation (C) strip mining (D) overharvesting (E) river channelization

26. Hamilton's Rule is a calculation of the strength in a population of _____. (A) sexual selection (B) group selection (C) natural selection (D) genetic relatedness (E) kin selection

27. What is a major consequence for plants and animals if current predictions of global warming are accurate? (A) Rates of natural selection will increase at the same pace. (B) New continental land masses will appear. (C) Water will be more widely available for plants and animals. (D) Anticipated changes in climate will occur faster than many organisms can move or adapt. (E) Many plants and animals will become smaller.

28. Which type of plants keeps their stomata open at night, but closed in the day? (A) C3 (B) C4 (C) CAM (D) C3 and C4 (E) C4 and CAM