Bio 360X—Toepfer
Exam II
Answer any FOUR of the following eight questions (20 points each).
1. Let’s say that a lion pride typically consists of 10 reproductively mature females. Imagine that a male
working by himself has a 30 percent chance of acquiring and defending a pride for 1 year. However, a pair
of males has an 80 percent chance of holding a pride for the same period. (1) Assuming that all the females
mate with the male of males that control their pride and produce one youngster apiece during the year, and
that both males in a two-male pride sire an equal number of young, should two unrelated males get together
to secure this harem of females? (2) What if the males are cousins? (3) Now imagine that the males are
half-brothers, but the dominant male manages to get 80 percent of all matings, and so 80 percent of the
offspring are his. Should the subordinate join a coalition with his dominant half-brother? In all your
calculations (yes, this requires some actual math) of inclusive fitness, identify the direct and indirect fitness
components.1
2. In a small African antelope called Kirk’s dik-dik, most males and females live in monogamous pairs.
Evaluate alternative hypotheses for monogamy in this species in light of the following evidence: the
presence of males does not affect the survival of their offspring; males conceal the female’s estrous
condition by scent-marking over all odors deposited by their mates in the pair’s territory; males sire their
social partner’s offspring; females left unaccompanied wander from the pair’s territory; some territories
contain five time the food resources of others; the few polygynous associations observed do not occupy
larger, or richer, territories than monogamous pairs of dik-diks.1
3. During reproduction, the best strategies for males and females are often conflicting. Discuss at least
three examples from mate selection or mating systems material in which the adaptive strategies differ. In
your discussion you should be considering the basics of how the strategies differ and why they are adaptive
for each gender. In addition, however, you should also describe situations in which one strategy might
“win” or describes how differing circumstances might change the “winner.”
4. When we observe foraging behavior we often find examples that seem to be maladaptive in which the
forager does not seem to be maximizing the amount of energy that could be consumed. Fully explain three
examples from class or from other sources. You should describe why the example appears at first to be
maladaptive and then explain how the behavior can be reinterpreted as an adaptation. If experimental
evidence is available, be sure to include it.
5. Many species were assumed to be monogamous because of strong social bonding between the partners.
With advances in genetic analyses, however, we are finding that many socially monogamous partners are
actually participating in extra-pair copulations (EPCs). Discuss the benefits to both males and females that
participate in EPCs.
6. Discuss the benefits of deceit in at least three different categories of behavior (e.g., mating). For each
category, use examples from lecture, the textbooks, or other sources. Why is deceit still so successful in
many of these cases even though we would expect that organisms might evolve the ability to better
discriminate between honest and deceitful message?
7. Let’s say that you have been hired to produce a weekly newspaper column covering the wonders of
animal behavior. Choose one of the articles that we discussed during this unit of material or another
relevant article from your book (there are a few more that touch on the topics that we covered). Write a
summary of that article that would be suitable for a general audience AND effectively explains the
behavior in ways that would make it educating and interesting to a non-scientist.
1
Questions modified from Alcock, J. 2005. Animal Behavior, 8 th ed. Sunderland: Sinauer Associates,
Inc. 564 pp.
8. In studying the courtship behavior of the empid flies, E.L. Kessel was amazed to find a species, Hilara
sartor, in which males gathered together to hover in swarms, carrying empty silken balloons. Females flew
to the swarm, approached a male, and received a balloon, which they held while mating occurred. In the
overwhelming majority of fly species, including some other empid flies, courtship does not involve the
transfer of any object from male to female. But in addition to (1) the empty balloon gifts of H. sartor and
(2) the “no courtship gifts” of some empids, males of other species in the group courted by (3) gifts of an
edible food item (a freshly killed dead insect), (4) gifts of a dried insect fragment wrapped in a silken
covering, or (5) gifts of an edible prey insect wrapped in silk. Suggest a sequence that minimizes the
transitions from a possible ancestral pattern to the empty balloon gift-giving behavior and explain your
reasoning for that sequence. How would you test your hypothesis? 2
2
Questions modified from Alcock, J. 2005. Animal Behavior, 8th ed. Sunderland: Sinauer Associates,
Inc., 564 pp.