Exam 2. Principles of Ecology. March 25, Name

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1 Exam 2. Principles of Ecology. March 25, Name N t = N o λ t N t = N o e rt N t+1 = N t + r o N t (1-N t /K) N t = K/(1 + [(K N o )/N o ] * e rt ) dn/dt = rn(1-n/k) N captured and marked initially = N marked at recapture N total N total recaptured ds/dt = -BSI - ds di/dt = BSI vi di - αi dr/dt = vi dr - gr dv/dt = rv cvp dp/dt = acvp dp dn 1 /dt = r 1 N 1 (K 1 N 1 α 12 N 2 ) dn 2 /dt = r 2 N 2 (K 2 N 2 α 21 N 1 ) Provide precise descriptions of the four, easily observed characteristics of natural selection. (5 pts, -2 pts for 1 st wrong) a. b. c. d. Pick or provide the best answers. If you don t see the right answer, please provide it! [5 points each, 50 pts total] 1. If p = the proportion of the A 1 alleles in a one-locus, two-allele system, and the number of individuals that are A 1 A 1 = 20, A 1 A 2 = 40, and A 2 A 2 = 60, then p = a b c d e Provide the genotype frequencies as proportions of the population from the above example assuming random mating. The numbers you provide must be correct to get credit. After one generation (3 pts) A 1 A 1 = A 1 A 2 = A 2 A 2 = After two generations (2 pt) A 1 A 1 = A 1 A 2 = A 2 A 2 = 3. When we test whether the above population is in Hardy-Weinberg equilibrium we discover X 2 = 7.5. If the critical X 2 value = 5.99 then a. the population is in Hardy-Weinberg equilibrium because p b. the population is not in Hardy-Weinberg equilibrium because p b. the population is in Hardy-Weinberg equilibrium because p > b. the population is not in Hardy-Weinberg equilibrium because p > e. none of the above is true. 4. Andrewartha and Birch (1954) argued which of the following factor was least important in determining the size of the summer population of Thrips? a. winter temperature. b. amount of spring rainfall. c. spring temperature. d. size of overwintering population. e. none of the above, they re all equally important. 5. What s the approximate doubling time of a population growing geometrically if it changed from 20 to 21 individuals in one year? a. 14 years. b. 40 years. c. 79 years. d. 95 years. e. 100 years. Principles of Ecology, Exam 2 Page 1 of 8

2 6. Geometric growth and exponential growth models can yield equivalent mathematical results if a. λ = r b. λ = ln(r) c. r = ln(λ) d. ln(r) = e λ e. none of the above. 7. Provide a graph of data that would be consistent with the resource availability hypothesis. Be sure to label your axes clearly with appropriate units. 8. Estimate the population of feral cats in Geneseo using the mark-recapture technique. On the first capture you catch 80 cats and mark them with ear tags. On the second capture you get 50 cats and find 10 are marked. You then discover that there was a regional cat party in town where large numbers of cats came from neighboring towns. What is your original estimate of the population? Population estimate = (4 pts) Based on the new information about the party the above estimate is (1 pts) a. too high b. too low Principles of Ecology, Exam 2 Page 2 of 8

3 9. Which of the graphs to the right represents logistic growth? a. Graph A b. Graph B c. Graph C d. Graph D e. all of the above. f. none of the above. 10. The condition of a female failing to ovulate because of exceedingly low body fat is an example of a a. biotic, intrinsic regulating factor b. biotic, extrinsic regulating factor c. abiotic, intrinsic regulating factor d. abiotic, extrinsic regulating factor e. all of the above. Short answer question. (5 pts) 1. Provide the graph of a population growing according to the logistic growth equation with N o = 100, r = 0.1, K = 500. On the same graph do this with N o = 600, r = 0.2, K = 500. Identify everything and be sure to label your axes. Principles of Ecology, Exam 2 Page 3 of 8

4 Three Ecology Models (pred-prey, competition, and SIR). Answer TWO. (15 pts ea., 30 pts total) 1a. Analyze the points on the left graph below. (1 pt ea., 5 pts total) a. b. c. d. e. 1b. Identify the lines on the graph below. (1 pt ea., 4 pts total) f. g. h. i. 1c. The dark dot in the left graph represents the initial condition (starting place). On the left graph draw the trajectory over time until it reaches an equilibrium point. (4 pts) 1d. Draw this trajectory (from 1c above) until it reaches the equilibrium on the right. (2 pts) Principles of Ecology, Exam 2 Page 4 of 8

5 2a. Analyze the following labeled points of the left graph below. (1 pt ea., 5 pts total) a. b. c. d. e. 2b. Identify the four lines on the graph below. (1 pt ea., 4 pts total) f. g. h. i. 2c. The dark dot on the left graph represents the initial starting populations for species 1 and 2. On the left graph draw the trajectory over time for this point until it reaches an equilibrium point. (4 pts) 2d. Draw this trajectory (from 2d above) on the graph on the right. (2 pts) Principles of Ecology, Exam 2 Page 5 of 8

6 3. The following questions are based on the SIR model provided at the top of the first page of this exam. a. Provide a graph of an epidemic curve that is likely if a disease agent, such as the common cold, spreads through the SUNY Geneseo campus. Be sure to label axes, provide approximate units for scale, and anything else necessary on the graph to demonstrate your understanding. (5 pts) b. What is the mathematical representation of the threshold susceptible population (S T ) if a disease exhibits dynamics according to this model? (5 pts) c. You have five minutes to tell the governor of NY what to do in the event of a deadly disease (large α!) that is beginning to spread through NY State. Assume only that the disease spreads according to this model. In decreasing importance provide four recommendations based solely on your result from this model. (Number 1 below is the best strategy.) (5 pts) Principles of Ecology, Exam 2 Page 6 of 8

7 Answer the following question. (10 pts) If a population grows with the following Leslie matrix, what will be the population in each of the next three time steps (N 1, N 2, and N 3 )? The provided population is from time step zero. Show your work. (3 pts) (2 pts) (1 pt) Calculate λ for the following time (t) steps a. t o -t 1 (2 pts) b. t 1 -t 2 (1 pt) c. t 2 -t 3 (1 pt) Principles of Ecology, Exam 2 Page 7 of 8

8 Extra Credit 1. What species is pictured to the right? (2 pts) 2. What was studied using the two men? (2 pts) 3. Name the species being held by these happy people. (2 pts) 4. Why are they smiling (what was the news associated with this image)? (2 pts) Principles of Ecology, Exam 2 Page 8 of 8

Exam 2. Principles of Ecology. March 10, Name

Exam 2. Principles of Ecology. March 10, 2008. Name N t = N o λ t N t = N o e rt N t+1 = N t + r o N t (1-N t /K) N t = K/(1 + [(K N o )/N o ] * e rt ) dn/dt = rn(1-n/k) N captured and marked initially