Concept explainers
(a)
To infer:
About the relative costs and benefits of large brains documented in the fossil records of certain lineages of humans and other animals.
Concept introduction:
Animals with larger brain size are considered as more intelligent and hence they are more successful than animals with smaller brain size. The larger brain size can also help an animal in obtaining mates and therefore can increase their survival.
The larger brain size involves a higher cost, but it is outweighed by the survival benefits that an animal gets.
(b)
To hypothesize:
In what way the natural selection might have favored the evolution of large brains despite their high maintenance costs.
Concept introduction:
Animals with larger brain size are considered as more intelligent and hence they are more successful than animals with smaller brain size. The larger brain size can also help an animal in obtaining mates and therefore can increase their survival.
The larger brain size involves a higher cost, but it is outweighed by the survival benefits that an animal gets.
(c)
To graph:
The data for 14 bird species and conclude about the relationship between brain size and mortality.
Concept introduction:
Animals with larger brain size are considered as more intelligent and hence they are more successful than animals with smaller brain size. The larger brain size can also help an animal in obtaining mates and therefore can increase their survival.
The larger brain size involves a higher cost, but it is outweighed by the survival benefits that an animal gets.
Graphical representation:
The graph between the mortality rate and deviation of brain size from expected is shown below:
Graph 1: Relationship between the mortality rate and deviation of brain size from the expected value. The x-axis represents the deviation of brain size from expected and the y-axis represents the mortality rate.
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Campbell Biology in Focus (2nd Edition)
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