Bio 312, Fall 2017 Exam 2 ( 1 ) Name: KEY

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1 Is in this individual Is in this individual Bio 312, Fall 2017 Exam 2 ( 1 ) Name: KEY Please write the first letter of your last name in the box; 5 points will be deducted if your name is hard to read or the box does not contain the correct letter. Written answers should be concise and precise; answers typically have short correct answers. Regrade requests cannot be made for exams completed in pencil for any reason. The exam has 130 points total 1. RELATEDNESS. Depicted to the right is a pedigree (family tree) similar to the one in class, representing males (squares) and females (circles) that mate to produce offspring. Males Females Compute the probabilities of alleles being shared between two individuals due to the ancestry depicted and write these in the boxes in the two grids below. The probability you will calculate is the probability of an allele in the individual listed in the column being in the individual listed in the row. A B C D For the grid on the left assume the allele is on an autosome of the individual the column represents. For the grid on the right assume the allele is on an X chromosome of the individual the column represents. Provide all answers to nearest (1 pt ea) Allele is on an autosome Allele is on an X chromosome Probability that an allele in this individual Probability that an allele in this individual A B C D A B C D A B C D A B C D

2 Bio 312, Fall 2017 Exam 2 ( 2 ) Name: KEY 2. HOW WE STUDY EVOLUTION. We discussed four basic methods (three in detail) that researchers use when studying evolution. Name the three methods we discussed in detail, provide an example discussed in class of a study that used this method, and provide an advantage and disadvantage of each form of study method in the box below. (12 pts) Study method Example from class One advantage One disadvantage Observation Giraffes Mammal ear fossils Bat altruism No dmg. to environment Low cost Is relevant to nature Can t separate factors Can t study hidden things Variation may not exist Experiment Bird tails and mites Coral snake coloration Redwing blackbird territories Can separate factors Can create added variation Limited to the present. May dmg environment Comparative Primate testes size Bird color and parasites Digit loss Ant colony sex ratios Big data sets (many species) Applicable across wide range Can time changes (w/ phylogeny) Combining different data set may be hard. Hard to get data if not there already. Must take phylogeny into account. 3. INTRA-SEXUAL SELECTION IN MALES. In class we discussed three broad categories of intra-sexual selection in males and provided examples. Provide the category name, a verbal description and an example discussed in class for these below. (9 pts) Competition model Contest Description Males compete in explicit contests for social rank that provides more mating success. Example from class Giraffes. Deer. Babirusa. Bower birds Territories Males maintain territories and females within mate with the resident male. Redwing blackbird. Elephant seals (video) Bluegill sunfish Sperm competition Males compete at the level of sperm since multiple males may potentially mate with each female Many examples

3 Bio 312, Fall 2017 Exam 2 ( 3 ) Name: KEY 4. EVOLUTIONARY CONSTRAINTS. Malaria is a disease that kills millions of individuals worldwide. A single DNA mutation in hemoglobin causes the protein to have a single altered amino acid which provides immunity to the malaria parasite. However, this mutation also causes sickle cell anemia, a deadly disease, in people who inherit two copies. This side-effect prevents it from increasing in frequency and causing humans to be able to evolve malaria resistance by this route. (a, 2 pts) The malaria example described above is a classic example of an evolutionary constraint that fits perfectly into one of the 4 sub-categories describe in the lectures. What is the technical term for this type of constraint? pleiotropic (c, 6 pts) There were 3 other types of constraint s we considered, list them: developmental selective functional The figure to the right depicts the outlines of turkey vultures and hummingbirds - the bodies have been scaled to the same size to show differences in the relative sizes of the wings. (d, 3 pts) Given that this trend is a general one, what prediction would we make about the wings of even larger birds like the albatross? Their wings would be even larger relative to the size of their bodies. (b, 4 pts) Since wings are, to a large extent, made of flesh and blood, this results in a limit to the maximum size of flying creatures. Considering the four types of constraints you listed above, which best describes this scenario and describe how the constraint works? These types of constraints are called FUNCTIONAL CONSTRAINTS. The example discussed in class was the observation that as land animals get larger their limbs get proportionally thicker which limits the size of land animals in a manner that is not the case for aquatic animals (e.g., whales). For wings this would mean that as organisms get bigger more and more of their flesh would be in the wings until eventually they would be all wing and no body not a viable organism.

4 Bio 312, Fall 2017 Exam 2 ( 4 ) Name: KEY 5. SEMELPARITY AND ITEROPARITY. Cole (and Charnov and Schaffer) modeled the factors that influence the likelihood for an evolutionary switch between different types of reproductive strategies; a similar approach can model other types of adaptations. (a, 5 pts) Consider a population of wildtype individuals that reproduce over a number of consecutive years and a mutant that causes individuals to produce twice as many offspring, but they are less likely to survive to adulthood. By producing more offspring the adults also have 75% the usual probability of surviving each year. What would this mutant's juvenile survival probability (C m) need to be to experience a fitness value equal to the normal wildtype individuals? Express C m in the form of an equality in terms of b w, C w and P m where these terms represent the values in the wildtype individuals and mutants repectively. Show all the steps in your derivation and express your final answer clearly. Wildtype growth rate: N = (b wc w + P w) N Mutant growth rate: N = (b mc m + P m) N They will have equal fitness when: (b mc m + P m) N = (b wc w + P w) N Which is: b mc m + P m = b wc w + P w From above: This gives: b m = 2b w and P m = 0.75 P w 2b w C M P w = b wc w + P w 2b w C M = b wc w P w C m = ( b wc w P w) / 2 b w or Cm = Cw/2 + (1/8) (Pw/bw) Cm = 0.5 Cw (Pw/bw) (b, 5 pts) Consider a diferent situation in which a population is growing by 20% per season and adults have a 75% chance of surviving each season. If the juvenile survival rate is 50%, what must the birth rate be? (express this as a decimal number to the nearest 0.001). Show all the steps in your derivation and express your final answer clearly Adult survival P = 0.75 Juvenile survival C = 0.50 For a population to grow by 20% This is when is N = 1.2 N = 0.75 N + b (0.5) N 0.45 N = b (0.5) N 0.45 = b (0.5) 0.45 / 0.5 = b 0.9 = b B = 0.9

5 Bio 312, Fall 2017 Exam 2 ( 5 ) Name: KEY 6. EVOLUTION OF DISEASE. For many viral and bacterial diseases, the initial strains are very virulent and cause a variety of unpleasant and life-threatening symptoms. Later strains are often milder in their symptoms and severity. (a, 4 pts) Consider our discussion of levels of selection - describe how selection may be acting in opposition at 2 different levels to change the degree of a disease's virulence and severity. Describe which level of selection seems to be more influential and why. Selection at the level of individual disease organisms selects for increased virulence, but selection at the group level within a host selects for groups with less virulence (lest their hosts die too soon and they go extinct). Group selection seems to be more influential since virulence declines rather than increases with evolution. (b, 4 pts) The conditions under which the opposing selection forces balance one another can vary with different types of disease transmission mechanisms. Keeping this in mind, would you expect the reduction of virulence and unpleasant symptoms described above to be more or less pronounced in "disease A" which is spread by intimate sexual contact or "disease B" which is spread via contact with fecal material? Assume a host population with high degrees of personal freedom, but an environment with poor sanitation. Explain your reasoning. Disease A would have the fastest expected rate of virulence decline because compromised individuals cannot infect others whereas disease B can spread even if the host is very ill. 7. EVOLUTION OF MATING BEHAVIOR. Drosophila males court females with a series of dances and songs (seriously) and females choose which males they mate with. In the Hawaiian archipelago (a series of islands in the Pacific with islands as old as 60 million years, but many younger than 10 million years) the female Drosophila exhibit a wide range of choosiness levels, with females on younger islands exhibiting less choosiness than on the older islands. Why might this pattern be seen? Provide an evolutionary explanation for the loss of female choosiness over time in Hawaii. (4 pts) Any well described argument can receive credit, two examples include: When the flies initially colonize new islands, individuals are rare and finding mates may be difficult. Females that are choosy may therefore not mate because they never encounter a male that meets their standards whereas females that are less choosy would mate - this advantage to lower choosiness would drive the evolution of behavior toward reduced choosiness. Newer islands have fewer species so the hybridization avoidance benefit may not exist and females that are less choosy have more matings at no cost (i.e., risk of mating with the wrong species). This advantage to lower choosiness would drive the evolution of behavior toward reduced choosiness.

6 Bio 312, Fall 2017 Exam 2 ( 6 ) Name: KEY 8. CROSSWORD PUZZLE - 1 pt each. c a r t i l a g e p a l e t l m u l l e r i a n c b i o l o g i c a l i h p p p e b a t e s i a n a o t t e s s e n t i a l i s t r r y i n f e r e n c e p h e n e t i c a p o s e m a t i c a c n s d p a r a p a t r i c h r o r e u s o c i a l i t y y u y p a l t r u i s m g t s y m p a t r i c i s ACROSS 1 Meckel's develops into two of the mammalian ear bones. 5 Mimicry in which both species are unpalatable or dangerous. 6 Species concept that focuses on the abilities of members to interbreed. 8 Mimicry in which only one species is unpalatable or dangerous. 9 Species concept used by Linnaeus. 10 When we design multiple hypotheses, instead of just one, to test ideas we are using strong. 12 Species concept that focuses on the measurable physical attributes of members. 13 Term for coloration used to warn potential predators. 14 Speciation caused by local adaptation to environments along a cline. 16 Term for when some members of the species forgo mating entirely. 17 Term for a helpful behavior that is not explained by kin selection. 18 Speciation facilitated by adaptation of different groups to microenvironments. 19 When the two sexes in a species look very different we say the species exhibits sexual. DOWN 2 Muller's describes the inevitable process of genomic degradation due to the production of deleterious alleles. 3 Speciation caused by physical barriers between two large groups. 4 Speciation caused by the physical isolation of a small group from the main group. 7 Specific term for a mating system where one female mates with multiple males. 11 A equilibrium is one where each player has no advantage to changing their strategy, assuming everyone else remains the same 14 Specific term for a mating system where one male mates with multiple females. 15 Term for coloration used to hide from potential predators. n d i m o r p h i s m u c

7 Bio 312, Fall 2017 Exam 2 ( 7 ) Name: KEY FOR THE REMAINING QUESTIONS USE YOUR SCANTRON FORM, MULTIPLE CHOICE: (2 pts each). (1) Which of the following concepts or examples from class was NOT used to argue or support the argument that that group selection can sometimes be stronger than individual level selection? (A) Sexual reproduction allows the removal of deleterious alleles from populations whereas asexual reproduction does not. (B) Sexual reproduction generates more variation in the next generation than asexual reproduction. (C) Populations with excessively high frequencies of the t allele go extinct. (D)The rate of fixation of advantageous alleles is higher in populations in which meiosis can occur. (E) Populations with high degrees of altruistic behavior do better than ones with more selfish individuals. (2) The presence of sexual dimorphism is an indicator of which of the following factors (A) Intra-specific competition (D) Allopatry (B) Inter-specific competition (E) Parapatry (C) Environmental diversity (3) A researcher has proposed that a population previously thought to be a member of a recognized species be considered a new species based upon the fact that the new population possesses several DNA nucleotide variants that are unique to that population. Which species concept is this researcher using? (A) Biological (C) Phenetic (E) Typological (B) Nominalist (D) Phylogenetic (4) Which of the following best characterizes the relationship between environmental change, mutation and adaptive change? (A) Environmental change occurs and because of this, advantageous mutations arise that make the organism better adapted to the new environment. (B) Environmental change occurs and because of this, mutations arise that are both good and bad, the good ones are selected for and the bad ones selected against, this makes the organism better adapted to the new environment. (C) Mutations are always happening in populations (regardless of whether the environment changes or not) and some mutations are advantageous and selected for whereas some are deleterious and selected against. (D) Mutations are always happening in populations (regardless of whether the environment changes or not), but advantageous mutations that are selected for only arise when the organism needs to evolve or it will go extinct. (E) Mutations only arise when an organism needs to evolve or it will go extinct, if the organism is thriving well in the environment then mutations don't occur. (5) What was the major insight demonstrated by the analysis of the prisoner's dilemma game? (A) Actions that are beneficial for individuals can lead to systems detrimental for all in the group. (B) Hawks prey on doves because they fly more quickly. (C) Playing aggressively always results in better long-term success. (D) Playing conservatively always results in better long-term success. (E) When trapped, escape behaviors are more useful than combative ones.

8 Bio 312, Fall 2017 Exam 2 ( 8 ) Name: KEY (6) Which is the correct order of development of (most) vertebrate digits? (A) (C) (E) (B) (D) (7) Which type of selection is predicted to increase phenotypic variance? (A) Directional (C) Fecundity E) Viability (B) Disruptive (D) Stabilizing ( (8) The term for an organism that reproduces only once during its lifetime is? (A) Iteroparous (C) Semelparous (E) Xyloparous (B) Perennial (D) Uniparous (9) Which of the following is the term for when two distinct phenotypes can be produced by the same genotypes depending on environmental cues. (A) Acclimation (C) Antagonistic pleiotropy (E) Phenotypic plasticity (B) Adaptation (D) Inter-generational conflict (10) Why will manatees never evolve gills? (A) Gills are too energetically expensive for manatees to possess based on their diet. (B) Gills are unique to fish and manatees are not fish. (C) Gills make endothermy impossible and manatees are warm-blooded. (D) Gills make parasitic infections too easy in mammals. (E) The developmental processes of lungs prevent the development of gills The following 3 questions are based upon the videos you watched in preparation for this exam. (11) Which organism was this video about? (A) Anglerfish. (C) Elephant seals. (E) Sharks. (B) Birds of prey. (D) Fruit flies. (12) Isabella uses which terms to describe the group of females associated with a single male? (A) A bower. (C) A harem. (E) A mating pod. (B) A cluster. (D) A lek. (13) What did Isabella remark was so surprising about the mating act itself? (A) That it took place in the water. (B) That it was so boring and gentle. (C) That more than two individuals often participated. (D) That the females initiated the act. (E) That there was a high risk of female mortality during the act. (14) At the end of the video a danger to the animals shown was described, what was this danger? (A) Bacterial infection. (D) Discarded fishing nets. (B) Climate change. (E) Hunting from local fishermen. (C) Competition from killer whales.

9 Bio 312, Fall 2017 Exam 2 ( 9 ) Name: KEY

10 Bio 312, Fall 2017 Exam 2 ( 10 ) Name: KEY Extra credit: Jokes must be biology related for credit 3 points for best joke in class. 2 points for a unique joke. 1 point for a shared joke (2+ students with same or very similar joke). 0 points if not an actual joke/pun.