Question

A researcher studying minnows, a type of fish, kept two groups of 20 fish in separate containers. The containers were linked by a pair of small tubes outfitted with a pump that constantly circulated water between both tanks. The researcher observed both groups of fish after placing a larger fish known to be a predator of minnows into one of the tanks. Fish in both tanks demonstrated alarm behavior. How can you explain these observations?

a. Fish in the tank that received the predator released alarm signals in chemical form. These compounds circulated and reached the other tank, eliciting an alarm response from the fish there nonetheless.
b. Fish in the tank that received the predator released alarm signals in the form of electrical signals. These compounds circulated and reached the other tank, eliciting an alarm response from the fish there nonetheless.
c. The predator introduced in one tank of fish released alarm signals in chemical form. These compounds circulated and reached the other tank, eliciting an alarm response from the fish there nonetheless.
d. Fish in the tank that did not receive the predator released alarm signals in the chemical form. These compounds circulated and reached the other tank and elicited an alarm response from the fish.

Answer 1

Minnows in one tank released chemical alarm signals upon encountering a predator, which were circulated to the other tank via connected water system, causing both groups to show alarm behavior.

Step-by-step explanation:

The observation that both groups of minnows demonstrated alarm behavior in separated tanks linked by a water circulation system can be explained by the concept of chemical alarm signals. When the predator was introduced to one of the tanks, the minnows in the presence of the predator likely released chemical compounds into the water as an alarm signal. Because the water was circulated between both tanks, these chemical alarm signals reached the fish in the second tank, despite them having no direct visual or auditory cues from the first tank, thereby causing them to also show alarm behavior.

The correct explanation for the observations described in the question is option a. Fish in the tank that received the predator released alarm signals in chemical form. These compounds circulated and reached the other tank, eliciting an alarm response from the fish there nonetheless.