A marine aquarium has been hoping to breed some endangered species in its intertidal zone tank, but has been unsuccessful. Their new student intern, who is taking Introductory Biology at the local university, suggested raising the water level. It worked! Several species spawned and the aquarists are thrilled. What is the best explanation for the behavioral response?

Question

A.  The added water diluted pheromones that built up in the tank over time, signaling over-crowding.
B.  The added water mimicked the higher tide that occurs monthly, which many marine animals use to synchronize their reproduction.
C.  It worked, but for a poor reason -- the chlorine in the poorly-prepared water was harmful to the animals, and they engaged in "last chance" mating in case they might die.
D.  The added water led to proliferation of algae and plankton, signaling an abundance of food that could support small fry and larvae.

Clarify Question
What is the key concept addressed by the question?

What type of thinking is required?


Gather Content
What do you already know about spawning behavior? What other information is related to the question?


Choose Answer
Given what you now know, what information is most likely to produce the correct answer?


Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

B.  The added water mimicked the higher tide that occurs monthly, which many marine animals use to synchronize their reproduction.


Clarify Question
What is the key concept addressed by the question?
     · The concept addressed in this question involves the conditions necessary to stimulate offspring production in marine species.

What type of thinking is required?
     · Analyze level:
       o This is an analyze question because you have to break environmental influences and gamete release into their component pieces to understand how they function.


Gather Content
What do you already know about spawning behavior? What other information is related to the question?
     · Marine species must synchronize release of eggs and sperm, since external fertilization occurs for these animals.
     · For animals that utilize external fertilization, the timing of male and female gametes must be synchronous.
     · Environmental cues such as high tide can sometimes serve as cues for the synchronous release of gametes.


Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
     · Overcrowding might stimulate, rather than inhibit, sexual reproduction.
     · It is incomprehensible to think that chlorinated water would be added to a tank in which marine creatures reside. If chlorinated water was added, it would be toxic to the fish and would not allow for even last chance reproduction.
     · Marine species must synchronize release of eggs and sperm, and often achieve this by responding to the once-a-month unusually high tide caused by the lunar cycle. Raising the water level would mimic this signal.


Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
     · Analyze level:
       o Answering this question correctly depended your ability to break down, or analyze, the timing of gamete release. If you got an incorrect answer, did you remember that gamete release must be synchronous, or that environmental cues can be used to synchronize the release of gametes? Did you have trouble breaking down the components of gamete release to determine the correct answer?