Problem 1
Species that have overlapping geographic ranges but do not interbreed in nature are said to be a. geographically isolated. b. reproductively isolated. c. influenced by genetic drift. d. hybrids.
Problem 2
Which of the following evolutionary mechanisms acts to slow down or prevent the evolution of reproductive isolation? a. natural selection b. gene flow c. mutation d. genetic drift
Problem 4
The time required for populations to diverge to form new species a. varies from a single generation to millions of years. b. is always greater in plants than in animals. c. is never less than 100,000 years. d. is rarely more than 1,000 years.
Problem 5
Adaptations a. match organisms closely to their environment. b. are often complex. c. help the organism accomplish important functions. d. all of the above
Problem 6
Prezygotic and postzygotic barriers to reproduction have the effect of a. reducing genetic differences between populations. b. increasing the chance of hybridization. c. preventing speciation. d. reducing or preventing gene flow between species.
Problem 7
Evidence suggests that sympatric speciation may have occurred or may be in progress in three of the following four cases. Select the exception. a. apple maggot fly b. squirrels on opposite sides of the Grand Canyon c. cichlid fishes d. polyploid plants (or their ancestors)
Problem 8
The diploid number of chromosomes in plant species A is 8 ; the diploid number in plant species \(\mathrm{B}\) is 16 . If plant species \(\mathrm{C}\) originated when a hybrid between \(\mathrm{A}\) and \(\mathrm{B}\) spontaneously doubled its chromosome number, what is the most likely number of diploid chromosomes in C? a. 8 b. 12 c. 24 d. 48
