the key:

part 2

24 points

12 points for the three currencies with equations (or very clear sentences that include all the factors in the equations). Note that for rate minimization, this can be phrased in many ways.

12 points for the three clear examples (e.g., 4 points each).

Three different currencies that might be optimized include: 1) an individual optimization problem of Net E Gain/(handling+search time), where Net Gain is the total amount foraged minus energetic costs of the foraging activities, 2) a parental bird that is foraging not to enhanced their individual fitness but Energy returns to their progeny (e.g., starling) where the equation is:

and 3) a third currency might include efficiency:

where the less is spent on foraging the higher the currency (or the more that the animal gains per joule of effort).

Currency one is individual fitness optimization and both the foraging crow and the foraging oystercatchers used this as the basis of their maximization solution. Currency 2 is individual fitness optimization via the maximization of returns to progeny, which as stated above included starling parents and their chicks. An example of a level of selection would be colony fitness of honeybees (or social insects) where a premium is placed on longevity of the bees and thus, minimizing the amount of energy spent in foraging is a key parameter for the level of the hive (e.g., kin selection benefit but prolonging the lifespan of workers).

TOP THREE REASONS for loosing points (on part 2):

1) People didn't understand what a "currency" was, and mistook it as a unit that scientists use to quantify true currencies (i.e. time, cost, gain, etc)
2) People didn't read the instructions, and failed to provide adequate examples for each currency
3) When providing examples, some people just wrote the name of the organism... "i.e. oystercatchers"... needed to relate the example back to the question and provide some detail regarding the system in question

Part 1

1A: 3 points= 1 pt. for name + 2 pts. for effect on mean of phenotypic trait (if stated in general terms, without explicitly stating how the mean will change, half credit give-1 pt.)

1B: 3 points=1 pt. for graph (graph needed to show distribution before and after selection-red and blue graphs below) + 2 pts. for effect on variance (needed to explicitly state if the variance in phenotypic trait increases or decreases after selection)

1C: 2 points for example (needed to state a specific animal; if explanation correct, but animal wrong half credit.)

The three modes of selection are directional, stabilizing (or optimizing) and disruptive selection.

Effect on mean: no change for disruptive and stabilizing, but moves with directional, Effects on variance (decrease for directional, stabilizing), increase for disruptive. Note: All forms of directional selection, such as artificial selection deplete phenotypic variation (though not required but remember for your understanding, artificial selection may deplete additive genetic variation as it strips away phenotypic variation).

Directional selection moves the phenotypic trait in a single direction.	Stabilizing selection removes the extreme individuals from a phenotypic distribution, and reduces phenotypic variation.	Disruptive selection removes individuals from the center of the distribution and increases phenotypic variation.

Examples (note that examples need to be explained: If you state an example of direction selection is bull frogs, that is not sufficient, explain the principle of directional selection with the bull frog example).

An example of directional selection is shown in the next figure where male size in bull frogs enhances fitness in a linear fashion (in this case a sexually selected trait).

An example of stabilizing (or optimizing selection) is selection for birth weight in humans. An example of disruptive selection is the African seed-cracker finches. Individuals with intermediate beak sizes survive poorly. (Galapagos finches are NOT an example of disruptive selection because the finches are different species and selection occurs within species)