8. How did the Grants test their hypothesis that differences in birds' songs can keep finches from breeding with members of other species?
a. They watched which birds were mating with each other and listened for the songs the
birds were singing.
b. They recorded birds singing on the island of Daphne Major for an entire breeding
season to see which type of song was used more often by each species.
c. They played the songs of medium ground finches and cactus finches through a
loudspeaker at different times, when individuals from both species were present, to see which
species responded to each song,
d. They played the song of the medium ground finch to medium ground finch males
through a loudspeaker to see if they would respond; they then played the song of the cactus
finch to cactus finch males to see if they would respond.
9. Explain the evidence presented in the film for your answer in question #8 above.
a. Males only came to the loudspeaker when the song of their own species was being played.
b. The type of song used more often during the breeding season was also the song sung by the
most abundant species.
c. During mating, birds sang the song of their own species.