BIO 130 Review QuestionsLecture 5/6: Evolutionary ProcessesJanuary 30, 2014(Ch 26.3-6)In order to be prepared for Exam 1, you should be able to answer the following questions. You can expect to see short answer questions about some of these topics on the exam. Therefore, I highly recommend that you practice answering these questions in a clear, concise manner, as you would on an exam. 1. For each type of natural selection (directional, stabilizing, and disruptive), be able to describe how the distribution of traits and genetic variation in the population is affected.a. Directional – decreases variation, shifting whole hill right or leftb. Stabilizing – decreases variation, makes hill narrowerc. Disruptive – maintains/increase variation, causes double hill2. Sexual selection is a type of natural selection. How is it different from ‘normal’ natural selection? In other words, what makes sexual selection a special case of natural selection?a. Selection based off of courtship and obtaining matesb. Female choice or Male-Male competitionc. Natural selection is also acting on these traitsd. Trade off – best traits attract mates but also predators3. Sexual selection can result from female choice and male-male competition. Give examples of the kinds of traits you would expect to be selected in response to each different selection pressure.a. Female choice – feather color, song/call, danceb. Male-Male competition – larger antlers, bigger size overall, bigger teeth, fighting for mate4. Why do males exhibit more sexually selected traits than females?a. Males are the ones in competition for females; these traits indicate that they are a healthy, smart choice for a mate. Without this they will not reproduce. 5. Be able to describe how sexual selection could cause the evolution of a trait within a population. For example, explain how sexual selection could cause male cardinals to be bright red assuming the males of this species were originally brown like the females.a. Due to female cardinals favoring males with bright red feathers (an indicator of good health),females select to mate with these males versus brown-feathered males. Due to variation in the population of the feather phenotype color and the phenotype can be passed onto future generations, there will be a greater number of these phenotypes passed onto future generations. Due to sexual selection, there will be a gradual adaptation in the cardinal population of males from brown feathers to the more favorable red ones.6. Evolution can result from natural selection, genetic drift, gene flow, or mutation. For each of these, give a brief explanation of how the process causes changes allele frequencies, what effect eachhas on average fitness in the population, and how each affects genetic variation in the population.a. Natural selection – due to variation in alleles in the population that are heritable, more favorable traits are passed on over time. It increases fitness and results in adaptation. Its effect on genetic variation is varied but usually maintains it.b. Genetic drift – any random process that causes some individuals in a population to survive and reproduce but not others, thus random mortality can change allele frequencies. It has a random affect on fitness and causes a decrease in genetic variation. It can result in a loss or “fixation” of alleles, but this is most likely to occur in smaller populations.i. Founder Effect – when one part of a population moves to a new environment establishes a new population. By chance, this new population is likely to have a different allele frequency than its original population. ii. Population Bottleneck – when suddenly a large part of the population is randomly wiped out due to fire, flood, human activity, etc. The small group of individuals left is likely to have different allele frequencies than original population by chance.c. Gene Flow – When two distinct population mix. Gene flow homogenizes allele frequencies. High gene flow causes similar population to occur. It causes random effects on fitness and increases genetic variation in the recipient population.7. What effect does genetic drift have in small populations? What effect does it have in large populations?a. Genetic drift in small populations has a very large effect versus a large population is not affected as much. 8. Different mechanisms of evolution often influence one another. How can genetic drift affect the process of natural selection in populations? (Hint: Think about its effect on genetic variation in a population and why this might be important for natural selection.)a. Due to the random loss or gain of different alleles into an environment, more favorable traits may be introduced, thus natural selection will occur when reproduction increases with those who have this new trait.9. What is the Founder Effect and how does it influence variation in a population? Which evolutionary process is it an example of? a. The Founder Effect is part of genetic drift. It is essentially when a part of the population leaves and establishes a new population on its own. This new population most likely does not contain all the allele frequencies that the original population did, and for this new population only those specific individuals’ traits will be passed on in that population.10. What is a Population Bottleneck and how does it influence variation in a population? Which evolutionary process is it an example of?a. Population Bottleneck is part of genetic drift. It occurs when a fire, flood, human activity, etc. causes a random portion of the population to be killed off. Thus the allele frequency has changed in this population from the original population.11. What is the main effect that gene flow (between two populations) has on the genetic similarity between the populations.a. Gene flow between two populations increases genetic similarity between the populations.12. Explain how high levels of gene flow can influence the process of adaptation within a population. Give examples (real or hypothetical) to illustrate a situation in which gene flow aids adaptation and one in which gene flow inhibits adaptation, and explain WHY it aids or inhibits adaptation in each example.a. Aids adaptation: For a population of birds with a low allele frequency or diversity, gene flowcould randomly introduces alleles that increase the fitness of the species, thus helping the population.b. Inhibits adaptation: For the other