Figure 39.4 The Behavior of Most Animals Is Influenced by the Periods

question 69

Multiple Choice

Figure 39.4
The behavior of most animals is influenced by the periods of daylight and darkness in the environment. Fiddler crabs' courtship behaviors are instead synchronized by the 29 1/2-day cycle of the moon. What is the adaptive significance of using lunar cues?

• A) The fiddler crab courtship ritual is highly visual, so individuals need the light of the full moon to be able to observe courtship displays.
• B) Egg maturation in fiddler crab females takes 29 1/2 days.
• C) By courting at the full and new moon, fiddler crabs link their reproduction to the times of the highest tides that disperse their larvae to safer, deeper waters.
• D) The algae that larval fiddler crabs consume for energy and metabolism bloom on a monthly cycle, so recently hatched larvae have plenty to eat during a crucial time of their lives.
• E) It takes about 29 days for a fiddler crab to reach sexual maturity.

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Definitions:

Internal Validity

The extent to which a study can demonstrate a causal relationship between variables, minimizing the impact of confounding variables.

External Validity

The extent to which the results of a study can be generalized to other situations and to other people outside of the experimental setting.

Construct Validity

The degree to which a test or instrument measures the theoretical construct or psychological concept it intends to measure.

Population

The total number of people under consideration.