9.17–9.18: Communication and the design of signals evolve.

The challenge of communication is central to the evolution of animal behaviors.

Question 9.28

Relative to birds, more mammalian species are:

  • a) polygynous.
  • b) monogamous.
  • c) polyandrous.
  • d) hermaphroditic.
  • e) sexually monomorphic.

Question 9.29

In a species such as pigeons, in which males are almost indistinguishable in appearance from females, the most likely mating system is:

  • a) monomorphism.
  • b) monogamy.
  • c) polygyny.
  • d) polyandry.
  • e) It is impossible to predict the mating system with only this information.

Question 9.30

If you find a species of fish in which males are much more brightly colored and larger than females, what might you infer about their mating system?

  • a) The degree of sexual dimorphism does not give any information about the mating system.
  • b) They are simultaneous hermaphrodites.
  • c) They exhibit parallel monogamy.
  • d) They are serially monogamous.
  • e) They are polygynous.

Question 9.31

Polygynous species:

  • a) usually employ external fertilization.
  • b) are usually sexually dimorphic, with males larger and more highly ornamented.
  • c) are usually sexually dimorphic, with females larger and more highly ornamented.
  • d) usually have males and females that are physically indistinguishable.
  • e) are more commonly found among birds than among mammals.