You Are Studying Directional Selection on Neck Length in Two

question 17

Essay

You are studying directional selection on neck length in two giraffe populations. Below you can see data on neck length (in inches) of the whole population and breeding parents for each of the two populations. $$\begin{array} { | c | c | c | c | } \hline \begin{array} { c } \text { Neck length of individuals } \\\text { in population 1 }\end{array} & \begin{array} { c } \text { Neck length of breeders } \\\text { in population 1 }\end{array} & \begin{array} { c } \text { Neck length of } \\\text { individuals in } \\\text { population 2 }\end{array} & \begin{array} { c } \text { Neck length of } \\\text { breeders in } \\\text { population 2 }\end{array} \\\hline 50 & 90 & 55 & 90 \\\hline 80 & 80 & 75 & 60 \\\hline 90 & 75 & 45 & 70 \\\hline 45 & 95 & 60 & 75 \\\hline 60 & 60 & 40 & 80\\\hline 35 & & 90 & \\\hline 95 & & 45 & \\\hline 40 & & 70 & \\\hline 75 & & 80 & \\\hline\end{array}$$ (a) Calculate the selection differential for each population. Show your work.
You also have data on the length of necks for parents and their offspring (offspring corresponding to each midparent listed in the adjacent cell). $$\begin{array} { | l | l | l | l | } \hline \text { Midparent pop 1 } & \text { Midoffspring pop 1 } & \text { Midparent pop 2 } & \text { Midoffspring pop 2 } \\\hline 85 & 84 & 80 & 65 \\\hline 90 & 88 & 75 & 90 \\\hline 75 & 75 & 85 & 55 \\\hline 65 & 62 & 65 & 75 \\\hline 70 & 69 & 70 & 85 \\\hline 80 & 82 & 95 & 75 \\\hline 95 & 94 & 60 & 80 \\\hline\end{array}$$ (b) Describe how you would use this data to calculate narrow sense heritability.
(c) Based on parts a and b, in which population would you expect to see the largest evolutionary change in neck length in the next generation? Explain your answer.

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