Homework- Biology 2010 Tree thinking exercise Recent analyses of genes called re
ID: 140803 • Letter: H
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Homework- Biology 2010 Tree thinking exercise Recent analyses of genes called retroposons support the hypothesis that there is a monophyletic group of mammals that originated and diversified in Africa. The data that support this conclusion, and the resulting tree, are shown here. The numbers across the top of the table identifly difflerent retroposons; the 1s and 0s for each species indicate that a particular retroposon is present (1) or absent (0). For each question, choose the single best answer. There are a total of 13 questions. Manatee Hyrax Tearec Elephant shrews Question 1 Sister groups (or species) are each others' closest relative-meaning that they share a most-recent common ancestor. For example, manatees and hyrax are sister groups on this tree, and elephant shrews are a sister group to aardvark + tenrec Based on the data given, when elephants are added to the tree they should be a sister group to: Manatee Hyrax Manatee +hyrax Aardvark Tenrec Aardvark + tenrec Elephant shrew Aardvark+tenrec+ elephant shrew Everyone (manatee + hyrax + aardvark + tenrec + elephant shrew)Explanation / Answer
Ans.1) When elephants are added to the tree they should be a sister group to Manatee+hyrax. Because of elephants and manatees+hyrax share, the most recent common ancestor and all these three are herbivorous in nature.
2.) The retrosposons 1-6 supports the hypothesis that all the species in the table are a part of a monophyletic group. because all the species having the common retrosponos 1-6.
3.) We would map the evolution of insect-eating species on the branch leading to Aadvark+tenrec+elephant shrew because only these three species are evolved as an insect-eating group whereas the other group is herbivorous in nature.
4.) The similarities between manatees and whales are due to homoplasy which means due to similarities in the underlying genetic and developmental processes. These similarities are the result of living in and adapting to the ocean environment.
5.) All of the species are alive today.
6.) The most primitive group is dependent on that which group will appear first in the fossil- the oldest one will be the most primitive. and which group is long lasting.
7.) The closest living relatives of elephant shrew are Aardvark and tenrec equally because all these three are having a recent common ancestor and all are insect-eating in nature.
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