07 gene flow, macroevolution, speciation, macroevolution in context Flashcards
How are biological species defined?
Members have the potential to interbreed in nature and produce viable, fertile offspring.
[Match each of the following statements to the most appropriate pre- or post- zygotic barrier to gene flow.] You successfully cross Bengal and Siberian tigers, but the resulting offspring are sterile.
Reduced hybrid fertility
[Match each of the following statements to the most appropriate pre- or post- zygotic barrier to gene flow.]
Temporal isolation
[Match each of the following statements to the most appropriate pre- or post- zygotic barrier to gene flow.] Polar bears and grizzly bears can produce viable fertile hybrids, but rarely do so because polar bears live out on the ice and grizzly bears live on land.
Habitat isolation
[Match each of the following statements to the most appropriate pre- or post- zygotic barrier to gene flow.] Many species of coral broadcast spawn, releasing sperm and eggs into the environment. Although eggs and sperm of different species meet regularly, hybridization is rare because eggs “reject” the sperm from species that are not their own.
Gametic isolation
[Match each of the following statements to the most appropriate pre- or post- zygotic barrier to gene flow.] Arctic charr and brook charr (two closely related fish in the trout family) occasionally hybridize but the hybrids rarely survive winter.
Reduced hybrid viability
[Match each of the following statements to the most appropriate pre- or post- zygotic barrier to gene flow.] I saw three species of booby coexist on the same rock in Galapagos during mating season. The three species have very different mating dances.
Behavioral isolation
I discussed Diane Dodd’s famous fruit fly experiments in class. Which of the following best describes the main conclusion of her study?
Habitat isolation and natural selection led to decreased gene flow between the two test populations within 40 generations.
In the oceans on either side of the Isthmus of Panama are 30 species of snapping shrimp. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago. The oceans were completely separated by the isthmus about 3 million years ago. Which of the following statements about this system make it a good example of allopatric speciation?
Each Pacific species has a sister species on the Atlantic side
Based on our discussion of snakes on the Ohio and Ontario shores of Lake Erie, which of the following best describes the relationship between adaptation and gene flow?
Gene flow slows down adaption
Female gray tree frogs prefer to mate with males that make long calls. Biologists determined that the offspring of long-calling males reach metamorphosis faster than the offspring of short call males. Which of the following is most correct?
Call length is an indirect but honest indicator of a male’s genetic qualities.
Which of the following best describes HGT?
Transfer of alleles across normal mating barriers
Why does HGT pose a problem for the Biological Species Concept?
HGT causes gene flow between otherwise unrelated lineages of organisms
The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information?
Postzygotic isolation exists between the two frog species.
Macroevolution is
evolution above the species level
