Q20

[Michelle5]

Hello! I was wondering if someone could please explain to me the functions of patrolling and then searching? In patrolling you are using electroreceptors and trying to respond to weak electrical fields, it's swimming along doing this, steadily wagging its bill from side to side...(line 32/33) is where I get confused. It says "until it encounters prey" well? isn't that using mechanoreceptors (it touched something) or can we assume "encountering prey" means the platypus felt the electric fields produced by the potential prey and then switches to searching behavior right after. Searching behavior being (A) capture the prey (B) distinguish what kind it is (line 48) and (D) use mechanoreceptors. Also, (E) is incorrect because we know nothing about the scent correct? I just wanted to make sure my reasoning is all correct in that answer choice "C" is the correct. We can assume the encounter is with the electric field of the prey. Thanks!!

[giladedelman]

Thanks for your post! You seem to be on the right track. This is the key section:

"When a platypus feeds, it swims along steadily wagging its bill from side to side until prey is encountered. It thereupon switches to searching behavior, characterized by erratic movements of the
bill over a small area at the bottom of a body of water, which is followed by homing in on the object and seizing it."

So as you said, patrolling is when the platypus swims along the surface, wagging its bill from side to side. Once it locates its prey--at a distance, so it must be through electroreceptors--it switches to search mode to find it and eat it.

Interestingly, the passage doesn't really tell us about how the platypus uses the mechanoreceptors. The focus is on the use of electroreceptors to find prey from a distance.

So (C) is correct: during patrol, the platypus is trying to pick up the electrical signals of its prey.

(A) is incorrect because in patrol behavior, the platypus hasn't located the prey yet.

(B) is incorrect because the passage doesn't say the platypus can distinguish among different types of prey.

(D) is out because this is all about stimulating the electroreceptors, not the mechanoreceptors.

(E) is out because the passage says nothing about their sense of smell.

Gosh, I feel like writing this post has made me noticeably nerdier.

[Michelle5]

Thanks! haha right?? Anything Platypus related in the LSAT is bound to be nerdy but it was a fun one to read! Thanks again for your help and affirmation

[GraceS579]

Hello!

I think I'm a bit confused about what "patrolling behavior" entails. I interpreted patrolling behavior to refer to "when a platypus feeds, it swims along, steadily wagging its bill from side to side until a prey is encountered" and searching behavior to being able to distinguish its prey due to the prey's weak electrical signals.

As for the patrolling behavior, I thought that the "UNTIL A PREY IS ENCOUNTERED" refers to tactile simulation (mechanoreceptors) and it's after the platypus has switched to searching behavior that it uses its electroreceptors to distinguish and feed on its prey. This is why I chose (D) for #20 and thought (C) referred to searching behavior. Could you please let me know where my reasoning has gone wrong?

Thank you,
Grace