27. You are investigating the costs and benefits of group living. You observe different sized
herds of an antelope (prey) species and collect the data on the success of predators that hunt
them. The graph below shows different group sizes across the x-axis, and each bar is the percent
of attacks by predators that were successful (i.e. an antelope was killed). Use these data to
answer the following questions 100 90 80 F 70 F 60 50 F 40 30 - 20 10 1 2-10 11-20 21-30 31-
40 41-50 Number of prey individuals (1) Based on this graph, what is one possible cost to an
individual antelope of living in a group? Coptoc radc (2) The antelope usually live in groups of
31-40 individuals. How could you explain this behavior in light of part a? well! 00yur that Size is
a lot that size s ot aser for Predlos to D Pix oot Indivicbats in that grouP and t them cun
Solution
a. (1) The graph here shows a correlation between the no. of prey individuals on the X-axis and
the percent successful capture on the y-axis, where with an increase in prey individuals (Group
size) the chance of capture by predators also increases. Therefore, one of the possible cost to an
individual antelope living in a group would be that, the larger the group they live in the higher
the chances becomes to be captured by the predator for an individual prey but not as a group.
b. (2) Living in a large group has its advantages and disadvantages, the larger the group other
than the disadvantage mentioned above in part (a), provides safety for each individual in the
group. Larger group means more eyes and ears to look out for predators, it increases the
difficulty for the predator to pinpoint its prey among the herd during the hunt but more
importantly, it increases the survival chance as an individual prey in a group.
herds of an antelope (prey) species and collect the data on the success of predators that hunt
them. The graph below shows different group sizes across the x-axis, and each bar is the percent
of attacks by predators that were successful (i.e. an antelope was killed). Use these data to
answer the following questions 100 90 80 F 70 F 60 50 F 40 30 - 20 10 1 2-10 11-20 21-30 31-
40 41-50 Number of prey individuals (1) Based on this graph, what is one possible cost to an
individual antelope of living in a group? Coptoc radc (2) The antelope usually live in groups of
31-40 individuals. How could you explain this behavior in light of part a? well! 00yur that Size is
a lot that size s ot aser for Predlos to D Pix oot Indivicbats in that grouP and t them cun
Solution
a. (1) The graph here shows a correlation between the no. of prey individuals on the X-axis and
the percent successful capture on the y-axis, where with an increase in prey individuals (Group
size) the chance of capture by predators also increases. Therefore, one of the possible cost to an
individual antelope living in a group would be that, the larger the group they live in the higher
the chances becomes to be captured by the predator for an individual prey but not as a group.
b. (2) Living in a large group has its advantages and disadvantages, the larger the group other
than the disadvantage mentioned above in part (a), provides safety for each individual in the
group. Larger group means more eyes and ears to look out for predators, it increases the
difficulty for the predator to pinpoint its prey among the herd during the hunt but more
importantly, it increases the survival chance as an individual prey in a group.
