Name________________________________Bio 44 first exam. Weds, Feb. 18, 2009Answer all questions: 6 points each.1. In a population 51% of the individuals exhibit the dominant trait. Assuming the Hardy-Weinberg Equilibrium applies, what percentage of offspring of the population should be heterozygotes for the trait. P2 + 2pq = .51, q2 = .49, q = .7, p = .3 2pq = 2x3x7 = .422. It has been stated that college graduates are less fit than others in the population. Whatis the basis of this argument and what evidence would you need to show that it is true? If fitness is defined as having more offspring that survive to reproductive age – then college graduates are less fit. Need to know survival. Note: this does not imply that thereis a genetic difference. There need not be to define fitness. We are talking offspring, not genes. 3. If two populations of a species are isolated from each other yet in identical environments, can speciation occur? How? Given a long enough time period of separation, different mutations occurring in the two populations will eventually cause them to become different species.4. Is there a foolproof way to tell whether or not two individuals belong to the same species? What is it? The two individuals may be of the same sex or dead, and Chihuahuas don’t mate with st. bernards. Studying DNA similarity is the most foolproof way, but even here there is a chance for error.5. Why is absence of oxygen essential for the origin of life? Oxygen oxidizes = breaks down organic molecules. No accumulation possible in the presence of oxygen.6. Two islands are the same size yet one has many more species on it. Present three possible explanations for this. Recent hurricane on one island, recent connection to mainland of one, recent change in island size, one island tropical, one temperate. Extreme isolation of one island.7. Is competition with other organisms good or bad for a species? Discuss. Good in that it causes better adaptation to conditions = specialization. Bad if those conditions (food source, etc.) disappear. Also bad if you are the species that is outcompeted.8. How are mainland animals likely to change if they colonize an island. Is this good or bad for them? If island is empty, arriving animals are likely to become more generalized and loose fear of predators. Ok if nothing happens, but bad if someone brings predators or rats to the island. They may also change size, etc.9. How can an obviously deleterious trait exist in a population at a higher frequency thanit is produced by mutation? Give at least three mechanisms for this. As a recessive trait; , through pleiotropy where the gene does good things as well as bad.If in the past it was beneficial and the environment has recently changed so it is now harmful. If there is heterozygous superiority. If sexual selection favors it 10. A living fossil is a species that has not changed much through a long period of time. Present two reasons why this might occur. It lives in an environment that has not changed for a long time. During this time it has become perfectly adapted to this environment. It has evolved on the ‘inside’ (chemisty), just not in external appearance.11. If, over several generations, an allele frequency in a population changes from 20% to 80%, do we know that it was selected for? Why or why not? Drift in a small population could do this without selection12. How have the causes of the decrease in birth rate for the human population changed over the last 100 years? Early due to rural to urban movement, and education of women and working women. Today often due to microeconomics allowing women to see hope, and media showing a better life is possible. Also China and India = govt policy and advertizing campaigns.13. Are human activities likely to increase or decrease the rate of speciation of animals? How? Animals use Allopatric speciation which involves separation. Humans are fragmenting environment (increase of isolation) but also moving animals about (decrease isolation). We may cause extinction of species but this is not speciation We may cause conditions to change, and animals would have to evolve to survive, but the new conditions would need to be constant for a long time.14. Under what conditions is the ability to increase population rapidly good. Under what conditions is this either bad or not of any benefit? If an r species = need to increase rapidly to achieve carrying capacity after population crash. If a K species, already at carrying capacity, increase of no benefit.15. One of the effects of Darwin was a change away from an anthropocentric view of theworld. What does this mean? Anthopocentrism says humans were the ‘goal’ of evolution, and the world was created for us. Darwin says we are just one of a million species, each with equal evolutionary potential.16. It has been said that modern medicine and our social programs are subverting our evolution by keeping alive those who otherwise would die. Discuss whether this is true and whether or not it is good or bad for human evolution. Modern medicine is causing an increase in survival of genes that in the past would have been deleterious. This increases the variation in the gene pool. Medicine is part of our environment and as long as it is available, these genes are not harmful. Also, not known what future environments will be so not known which genes will prove beneficial17. What does ‘survival of the fittest’ mean? How do we define fitness? Fitness = having the most offspring that survive to reproduce = carry on the genes. Fitness does not mean having good genes, except in terms of