Unformatted text preview: QUIZ 7 [5 pts] Name_______KEY__________________ BIOLOGY 325H
1. [2 pts] Hamilton's Rule states that for selection to favor genes which produce an altruistic behavior, that behavior must satisfy the equation 'rB > C'. Define the r and B variables in a few words, being careful to state whether the variable refers to the altruist or the recipient: r the degree of relatedness of the altruist and the recipient, e.g. if the altruist is a sibling of the recipient, their relatedness is 0.5 because they share 50% of their genes B the benefit the recipient gets from the help provided by the altruist, i.e., how much the recipient’s fitness is increased in terms of number of offspring 2. [2 pts] Why is survivorship plotted on a log scale when we use the cohort data from a life table? If there is a constant rate of survivorship (or death) per time period for a cohort, then plotting the data on a log scale will cause the trend to be linear. So we plot survivorship on a log scale to make it easier to see when there is a constant rate of survivorship. (See the example graphs below of the same data on normal and log scales.)
12,000 10,000 10,000 SUVIVORSHIP 1,000 8,000 6,000 100 4,000 2,000 10 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 TIME
3. [1 pt] Give two reasons why a population cannot increase exponentially indefinitely? There were many possible answers here. As long as you identified two limiting factors, e.g., food availability and suitable territories, you were given credit. ...
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