EVOLUTION
7.6 Questions 6-9
6)All dolphin species have hundreds of defective genes that are involved with olfactory function in other mammals. There is no evidence to believe that mutations occur any more frequently in dolphins than in other species. If this is true, why are there not many of the same defective genes in land mammal.
Olfactory is basically a fancy word for smell. It's because dolphins don’t really require the sense of smell since they are in the ocean so it really isn't used. It isn't a harmful mutation if the sense of smell were to disappear and the dolphin would still be able to reproduce normally without it. On the other hand, the sense of smell in humans and other mammals is essential to survive. It would be difficult to remain "fit" without a sense of smell and most mammals wouldn’t live long enough to reproduce without a sense of smell. No sense of smell in mammals is a harmful mutation and harmful mutations aren't always passed on to future generations.
7) Modern lemurs are found only on Madagascar Island off the east coast of Africa. However, fossils of ancient lemurs have been found thousands of kilometers away in India, where there are no lemurs. Consult figure 7 on page 312 and provide a possible explanation for this finding.
This is possible because back when the Earth was in the Pangea state, the east coast of Africa and Madagascar were really close to India. That way Lemurs from Madagascar could have easily went to India however over time as the continents began to move apart the Lemurs in India died off but the Lemurs in Madagascar thrived.
8) Copy the following DNA base sequences into your notebook. They are all short samples taken from what appear to be matching chromosomes in closely related species. Compare the sequence in Species A with that of Species B, and then compare the sequence of Species A with that of Species C.
Species A : GGTAA AACAG CCTTA AGCGCC
Species B: GGTAA CAACA GCCTT AAGCGC
Species C: GCTAA AACAG CCCCA AGCGGC
Species A and B
Species A : GGTAA AACAG CCTTA AGCGCC
Species B: GGTAA CAACA GCCTT AAGCGC
A, C was inserted
Species A and Species C
Species A : GGTAA AACAG CCTTA AGCGCC
Species C: GCTAA AACAG CCCCA AGCGGC
C was changed to B
a) Is there any evidence that one species experienced a single base "insertion" Mutation? Explain.
Yes, species B had a single base insertion because a Mutation C was inserted
b) Which two species are probably more closely related?
Species A and C are more closely related
9) Humans are one of a small number of mammals that are unable to synthesize vitamin C. Instead, we obtain vitamin C in our diet. Humans have a pseudogene that is homologous to a gene involved in vitamin C synthesis in other mammals.
a) Is the presence of this gene surprising? Why or why not?
This Is not surprising because synthesising it means creating. Humans don’t need to create it because we take in a lot of Vitamin C through our diet. We eat a lot of food such as oranges that contain Vitamin C and take it in through our diet. So creating Vitamin C isn't necessary.
b) What does it suggest about human evolution?
It means humans have had an ancestor that was able to synthesize Vitamin C. However that gene wasn’t necessary as humans evolved and it became a pseudogene.