Reactive and proactive aggression.

1. Biologists distinguish between reactive and proactive aggression.
   a. Describe this distinction (2 pts)
   b. Classify the following scenarios as either reactive or proactive: (5 pts)
   1) A lion stalks and kills a gazelle.
   2) A male baboon kills all of the juvenile baboons after taking control of a troop.
   3) A woman smothers her newborn infant because she has another infant who is still nursing.
   4) A serial killer claims his thirteenth victim.
   5) A man kills his wife after finding her in bed with his neighbor.
2. In evolutionary terms, a person’s life is valued according to the sum of his/her current reproduction and expected reproduction in the future.
   a. Explain why a newborn infant has a relatively low reproductive value. (2 pts)
   b. Explain why an infant in Somalia has a lower reproductive value than an infant in the United States. (2 pts)
   c. Explain why a 45-year old woman has a relatively low reproductive value. (2 pts)
   d. Explain why a 45-year old man could have a higher reproductive value than a 45-year old woman. (2 pts)
3. War represents an organized process by which two or more groups of people systematically kill each other’s members for access to resources. This
   behavior creates an opportunity for group selection.
   a. Explain the difference between group selection and the natural selection of organisms. Start by describing each process and then note the key
   difference(s). You may consult references outside of class, but your explanation must be in your own words. (4 pts)
   b. Give a historical example of a group whose reproductive success was amplified by war. (2 pts)
4. Setting aside serial killers, most killings make sense in evolutionary terms.
   a. Describe the most likely victim of a domestic murder perpetrated by a man. (2 pts)
   b. Describe the most likely victim of a domestic murder perpetrated by a woman. (2 pts)

Sample Solution