Evolutionary Analysis Chapter 1 questions with correct answers

The pope said " (HIV) cannot be overcome by the distribution of condoms. On the contrary, they increase it" Is the popes first statement correct? How about his second statement? How do we know? Answer The Pope's first statement is that Africa's problem with HIV/AIDS "cannot be overcome by the distribution of condoms." The statement is true in that no single strategy will prevent the transmittal of HIV/AIDS. For instance, condoms provide some protection from sexually transmission of HIV/AIDS, but they would not prevent an infected mother from passing the virus to her babies via breast milk. The Pope's second statement is that the distribution of condoms actually increases the problem of HIV/AIDS transmission. We know this second statement could be argued against from numerous data collected in South Africa and elsewhere showing that consistent use of condoms reduces HIV infection significantly. There is no data to suggest the use of condoms increases the problem of HIV/AIDS transmission. Review the process by which the HIV population inside a human host evolves resistance to the drug AZT. What traits of HIV contribute to its rapid evolution? How might a similar scenario explain the evolution of antibiotic resistance in a population of bacteria? Answer HIV has a very high mutation rate, a rapid reproductive rate, and an enormous population size. This means that at any given time, a human infected with HIV is carrying tens of millions of HIV virions with millions of different random mutations. Inevitably, a mutation will occur that confers resistance to AZT. (This will typically be a mutation that causes greater selectivity in the active site of the reverse transcriptase enzyme.) Notice that the HIV population has heritable variation for resistance to AZT before exposure to AZT. However, at this stage the resistance to AZT occurs only in one or a few virions out of the billions. In the other examples of this type of evolution, such as in the evolution of microbial resistance to antibiotics, we expect similar outcomes. It would take longer for the evolution of the resistant strains of bacteria, when compared to evolution of the HIV virions, which might happen within an individual patient. However, bacteria easily share their anti