Biology 14
Third Essay Assignment
Due: Tuesday, April 12, 11:30 AM
Drawing upon what you have learned in Biology 14 up through the section on Human Physical
Evolution, write an essay of 5 typewritten, double spaced pages on what you consider to be the most
important ideas in each of the two books about the origin and evolution of human behavior by
Richard Wrangham, Demonic Males: Apes and the Origins of Human Violence, and Catching Fire:
How Cooking Made Us Human. It would be best to read Demonic Males first, then Catching Fire,
and it will be important background to those books to take in the related films, lectures, handouts and
readings on ape social evolution, human physical evolution and human social evolution up to
wherever we are in lectures the Thursday (April 7) before the before the essay is due.
Richard Wrangham was trained as an evolutionary biologist and behavioral ecologist, and he did his
PhD thesis research on the behavioral ecology of chimpanzees at Jane Goodall’s Gombe Research
station on the shores of Lake Tanganyika. You already have a pretty good idea of the evolutionary
social theory he brought to his study of chimp behavioral ecology at Gombe and to his analysis of ape
social evolution in general. From our brief forays into animal behavior and population biology you
have an idea about what” behavioral ecology” is about: the study of how an animal’s behavior is
adapted to the environment in which it lives. To spell this out a little more, “behavioral ecology” is
the study of how an animal’s behavior is adapted to/ correlated with its source of food (its nutritional
value, energy content, distribution in time and space, time required to procure, process and digest); its
mating system (polygynous, monogamous, polyandrous, promiscuous); its size, mobility and
nutritional needs; differences between the sexes in size, nutritional requirements, mobility and
strength; its schedule of birth, maturation, reproduction and senescence; its predators (by members of
its own social group; how often predators are encountered; its ability to escape or defend itself, either
alone or with the help of others); the nature, distribution and transmissibility of disease pathogens;
the costs and benefits of individual and coalitional aggression and cooperation within a social group;
and the costs and benefits of intergroup aggression. This all may seem like a bit much, but the
upcoming lectures, films and handouts will show you how many of these factors come together in
effecting and affecting social evolution in general and in apes and humans in particular.
You will find in these two books that Wrangham draws upon most of these interrelated factors in
trying to figure out (=develop testable hypotheses for) why the very different mating systems and
social behaviors of apes have evolved to be the way they are, what influence the interaction of these
factors had in the unique physical and social evolution of humans (Demonic Males) and how these
factors further interacted with the discovery of the use of fire in cooking 2 million years ago in
causing the evolution of the first members of the genus Homo (Catching Fire). The idea that the use
of fire for cooking had a transformative effect on human physical and social evolution is a brand new
and (to some workers in the field) radical theory of human origins. Like all good theories, though, it
explains quite a lot and it makes lots of predictions that can be tested in many ways (by archaeology,
paleontology, physiology and molecular genetics). And this is what makes Catching Fire so exciting
to read, especially as a sequel to Demonic Males.