Questions over Speciation 


1. In Alabama there are many species of treefrogs that breed at the same time. Sometimes a mistake happens and a male of one species fertilizes the eggs of a female belonging to another species. The hybrid youngster grows up and does well. When it becomes an adult other treefrogs don’t want to mate with it. This is an example of _________.

 

          a. temporal isolation 

          b. postzygotic isolation

          c. gametic isolation 

          d. mechanical isolation


2. Two closely related beetle species can produce hybrid offspring in the laboratory but in their natural environment they don’t. This is because the one species lives up in oak trees and the other species lives on the ground. Because they live in different parts of the environment the two species don’t come in contact with each other. This is an example of _________.

 

          a. temporal isolation 

          b. ecological isolation

          c. mechanical isolation 

          d. behavioral isolation


3. Which of these is an example of natural selection?

 

a. There is a species of moth that occurs in shades of gray that vary from very light gray to dark gray. This species often sits on the trunks of trees. The medium and dark gray moths blend in very well, but the very light gray moths are easy to see. As a result most of them get eaten by predators before they can reproduce. Over time, the number of light gray moths in the population has decreased and the number of darker moths has increased.

b. The ancestor of modern corn had a few, tiny kernels on each ear. Humans selected plants with the most and biggest kernels and used the seeds from these plants to plant their next year’s crops. Over a number of years of doing this corn plants were modified into what we know today.

c. The ancestor of the domestic dog was the wolf. Humans took wolves and bred those individuals which had certain desirable traits. After thousands of years of selectively breeding for certain traits we now have dog varieties that are as different as poodles and St. Bernards.

          d. All of these are examples of natural selection.


4. Which of these is an example of allopatric speciation?

 

a. A small group of fruit flies from the U.S. mainland somehow got to Hawaii. The fruit and climate in their new home was different than what they had experienced on the mainland. Over time this population of fruit flies on Hawaii adapted to the local environment. During the process a number of changes occurred in the Hawaiian fruit flies and they eventually became a new species.

b. A species of insect was accidently transported from South America to Australia. The transported insects did well in their new home and adapted to the local conditions. After many years they had changed sufficiently to be considered a different species than the insects in South America.

c. A small group of iguanid lizards from Ecuador made it out to the Galapagos islands. Once they made it to the islands they quit eating leaves and started eating seaweed. They became adapted for swimming in the ocean and made a number of other changes in their anatomy, behavior, and ecology. After many years, this group of lizards became a species that was quite different from its ancestors in Ecuador.

          d. All of these are examples of allopatric speciation.


5. Which of the following PREVENTS two populations from becoming different?

 

          a. gene flow 

          b. genetic drift 

          c. natural selection 

          d. nonrandom mating


 6. The ancestors of rabbits and deer had digestive tracts that were adapted for a generalized diet. As rabbits and deer became adapted for a strictly plant diet, changes occurred in their teeth and digestive tracts to allow them to survive as vegetarians. Over time the digestive tracts of rabbits and deer have become very similar. This is an example of __________.

 

          a. adaptive radiation 

          b. punctuated equilibrium

          c. convergent evolution 

          d. artificial selection


7. A population’s gene frequency should NOT change if ____________.

 

          a. the population is large    ` 

          b. there is random mating

          c. there is no natural selection 

          d. all of these


8. The modern dog is descended from wolves. Humans selected animals with particular traits and bred them. This is an example of __________.

 

          a. artificial selection 

          b. natural selection

          c. convergent evolution 

          d. adaptive radiation


9. Allopatric species ____________.

 

          a. occur in the same place 

          b. are closely related species

          c. are species that look alike 

          d. do not occur in the same place


10. Which of these is an example of a prezygotic isolating mechanism?

 

a. Two closely related species of insects occur in the same place, but one lives up in the trees and never spends time on the ground, the other species lives in the grass and never spends time in the trees.

b. Two species of closely related mice occur in the same area. One of the species is active and reproduces at night while the other species is active and reproduces during the day.

c. Several closely related salamander species that look very similar breed together in the same ponds. Each species has a unique set of courtship behaviors which prevent crossbreeding between related species.

          d. all of these


11. When the original finches reached the Galapagos Islands they survived and colonized all of the islands. The islands had different environments and as the birds adapted to these, changes occurred in the birds and eventually there were about a dozen species of finches that had come from the original ancestors. This is an example of ___________.

 

          a. convergent evolution 

          b. artificial selection

          c. adaptive radiation 

          d. hybridization


12. Use the Hardy-Weinberg Equation to answer the next questions. If you have a gene with two alleles and q = 0.3 what percent of the population is homozygous dominant?

 

          a. 30% 

          b. 70% 

          c. (0.3)(0.3) = 0.09 = 9% 

          d. (0.7)(0.7) = 0.49 = 49%


13. What percent of the population in the last question is heterozygous?


          a. 70%

          b. 42%

          c. 49%

          d. 21%


14. If 70% (= 0.7) of the alleles for height in a plant species are T and 30% are t, what percentage of the population is tt?

 

          a. 30% 

          b. 0.7 x 0.3 = 0.21 = 21%

          c. 0.3 + 0.3 = 0.6 = 60% 

          d. 0.3 x 0.3 = 0.09 = 9%