Passage VI
Females of the New World tree frog Hyla ebraccata are strongly influenced in their choice of a mate by advertisement calls (calls made by males to attract females). Thus, the reproductive fitness of a male is dependent on the characteristics of his advertisement call.
Advertisement calls differ in their pulse-repetition rate (PRR), measured in hertz (Hz). Natural populations of Hyla ebraccata show low variability for PRR. A researcher hypothesized that a greater percent of female frogs would be attracted to a call with a PRR equal to the mean PRR of the population than would be attracted to a call with an alternative PRR.
The researcher located and recorded the advertisement call of a male frog, then captured, marked, and released thefrog. This procedure was repeated with other frogs from the same population until 60 recordings were obtained, each from a different frog. The mean PRR was found to be 100 Hz. Next, the researcher collected 25 gravid frogs (frogs carrying unfertilized eggs). Then the following experiment was conducted.
Experiment
In each trial, a single gravid frog was placed in a small arena (built from foam padding) with 2 speakers at opposite ends (see Figure 1).
32. By marking the male frogs as part of the procedure for obtaining 60 recordings, which of the following outcomes was the researcher trying to avoid?
Your Answer is
Correct Answer is H
Explanation
Examine the purpose of the experimental design. The purpose of marking is mainly to prevent repeated capture, to prevent repeated recording of the frog's data, and to prevent the frog's data from affecting the final average