In areas of permafrost, stands of black spruce are frequently observed in the landscape, while other tree species are noticeably absent. Often these stands are referred to as "drunken forests" because many of the black spruce often "lean over" (that is, they are displaced from their normal vertical alignment). What is the most likely explanation for the unusual growth of these forests in this marginal habitat?

#Question id: 3273

#Unit 11. Evolution and Behavior

The number of forward mutations is equal to the number of reverse mutations then

a) Population is in equilibrium for forward and reverse mutation rates

b) The population is being in Hardy–Weinberg equilibrium

c) No further change in allelic frequency

#Question id: 3276

#Unit 11. Evolution and Behavior

Which of these conditions are always true of populations evolving due to natural selection?

Condition 1: The population must vary in traits that are heritable.

Condition 2: Some heritable traits must increase reproductive success.

Condition 3: Individuals pass on most traits that they acquire during their lifetime.

#Question id: 3277

#Unit 11. Evolution and Behavior

Which of the following describes the most likely order of events in allopatric speciation?

#Question id: 3278

#Unit 11. Evolution and Behavior

What does the biological species concept use as the primary criterion for determining species boundaries?

#Question id: 3279

#Unit 11. Evolution and Behavior

Which two of the following have operated to increase divergence between mosquito fish populations on island?

a. improved gene flow

b. bottleneck effect

c. sexual selection

d. founder effect

e. natural selection

#Question id: 3280

#Unit 11. Evolution and Behavior

Small populations are threatened by the loss of genetic diversity from

a. Inbreeding

b. Genetic drift

c. Limited mating