Question

Could someone please check my answers?

1. A researcher uncovers a fossil in South America that looks quite similar to a species that currently lives in Africa but does not resemble other South American species. The climate and vegetation in the two locations are very different. What is the MOST likely explanation?

A. The fossil must have been transported across the ocean during storms.

B. The species are probably not closely related due to convergent evolution.

C. There was probably an aquatic common ancestor to both species that was capable of migrating from one location to the other and that preferred conditions in Africa, so it was more common there.

D. A common ancestor of the species was found in both places when the continents were closer together, and its descendants went extinct in South America.

(I think it's D)

2. You are interested in trying to work out whether adaptive radiation in mollusks occurred after the Cretaceous extinction. What sort of data would you need to collect?

A. You would need to work out the total number of species present in different locations at the present time.

B. You would need to examine the number of species present before the extinction event with the number present after the extinction event.

C. You would need to determine the number of species present before the extinction event and the number present today.

D. You would need to work out the number of species present immediately after the extinction only.

(I think it's B)

3. Which of the following gives the BEST example of data that you could use to determine whether a mutation in a developmental gene was responsible for speciation in a particular group of animals?

A. You could only use standard techniques to sequence the gene and see whether it differed in different species.

B. You could compare the sequence of the gene in different species and see the effects of different forms of the gene in genetically modified organisms.

C. You could use genetic engineering to turn the developmental gene on and off to determine what it does within the group of animals that interests you.

D. You could examine closely related groups of species to see whether they have the identical gene.

(I think it's D)

4. From a lifetime of observation, you know that birds have feathers. What is the MOST likely explanation for how feathers evolved?

A. Feathers evolved because of their value for flight.

B. Feathers evolved because it is not possible to fly without them, so wings would not have evolved it feathers had not developed first.

C. Feathers developed from a random mutation in a developmental gene, which allowed a full wing to form once it was turned on and fully expressed.

D. Feathers evolved because they helped to insulate birds and served other functions, then were later helpful in flying and became more specialized for that purpose.

(Umm I thiiink it's D..?)

5. Adaptive radiation often occurs after a mass extinction. If you were examining fossil beds and found evidence of the rapid appearance of new species in an apparent adaptive radiation event, could you conclude that a mass extinction had occurred?

A. yes because the presence of adaptive radiation means that there must have been newly vacated niches to fill

B. yes because the appearance of new species always means that adaptive radiation has occurred, and no further data is needed to answer that particular question

C. no because speciation and adaptive radiation can occur for other reasons, such as substantial environmental changes; you would need to examine earlier fossils to know more

D. no because there is not enough evidence to know whether speciation occurred

(I think it's C)

Thank you sooo much for your help in advance. I really appreciate it :D

Answer 1

All of the above answers seem correct.

1. D. A common ancestor of the species was found in both places when the continents were closer together, and its descendants went extinct in South America.

2. B. You would need to examine the number of species present before the extinction event with the number present after the extinction event. (to compare you need data of before and after extinction).

3. D. You could examine closely related groups of species to see whether they have the identical gene. but the option C. (You could use genetic engineering to turn the developmental gene on and off to determine what it does within the group of animals that interests you.) can give you a more accurate results.

4. D. Feathers evolved because they helped to insulate birds and served other functions, then were later helpful in flying and became more specialized for that purpose. (yes it is correct).

5. C. no because speciation and adaptive radiation can occur for other reasons, such as substantial environmental changes; you would need to examine earlier fossils to know more.