Behavior Chapter 51 U104PP

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Behavior- Chapter 51 U104PP
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• Concept 51.5 Natural selection favors behaviors
  that increase survival and reproductive success
• The genetic components of behavior evolve through
  natural selection
• Behavior can affect fitness
• Through its influence on foraging (a component of
  survival) and mate choice (a component of
  reproduction)

Remember Fitness is a measure of reproductive
success
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Foraging Behavior

• Optimal foraging theory
• Views foraging behavior as a compromise between
  the benefits of nutrition and the costs of
  obtaining food
• Natural selection should optimize foraging
  behavior (reduce the cost of foraging per
  benefits)

Fitness SURVIVAL reproduction
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Energy Costs and Benefits

• Reto Zach
• Conducted a cost-benefit analysis of feeding
  behavior in crows
• The crows eat molluscs called whelks
• But must drop them from the air to crack the
  shells

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• Zach determined that the optimal flight height in
  foraging behavior
• Correlated with a fewer number of drops,
  indicating a trade-off between energy gained
  (food) and energy expended

Total flight height (number of drops ? drop
height)
Height of drop (m)
Figure 51.22
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• In bluegill sunfish
• Prey selection behavior is related to prey density

At high prey density, the sunfish were choosy and
focused on larger prey more energy benefit per
cost
At low prey density, the sunfish needed all prey
for resources and were therefore less selective
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Risk of Predation

• Research on mule deer populations
• Has shown that predation risk affects where the
  deer choose to feed

Optimal foraging theory predicts prey will forage
in ways to minimize predation risk. Since they
are more vulnerable to mountain lion attacks in
the forest edge, they use that habitat the least.
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Mating Behavior and Mate Choice

• Mating behavior
• Is the product of a form of natural selection
  called sexual selection

Fitness survival REPRODUCTION
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Courtship Behavior

• Animals produce signals to communicate with
  potential mates (and with members of their own
  sex)
• A stimulus-response change often occurs, in which
  the behavior of one individual releases a
  behavior by another
• Signals can be visual, chemical (pheromones),
  auditory, tactile, electrical.
• Signals are species-specific (e.g., fire-fly
  flashing frequencies) to ensure proper mate

Examples?