#13 - Shelton: The recent sharp decline in the number

[Administrator]

Please post your questions below!

[SamSachsDE]

Please post your questions below!

I'm a little confused by the wording of the correct answer. When it says "ranges" is it saying that the Moose and Deer inhabit similar areas, so the deer impact the moose population, but in the other are they don't interact? I'm thinking "home home on the range" for the use of this term.

[Malila Robinson]

Hi SamSachsDE,
Range refers to the area where the animals are roaming (moving around). So in Russo's example they might inhabit the same region, but if the deer stay to the east of the region and the moose to the west then the parasites may not be as much of an issue. And in Shelton's example if the ranges overlap within the region then the spread of the parasite would be more likely.
Hope that helps!
-Malila

[ameliakate]

I selected the right answer for this question, but I briefly considered C. Answer C seemed almost like an alternative explanation. The moose population wasn’t falling because the wolves preyed on a wider variety of species, whereas this was not the case in the declining region. I opted for answer D because it connected the moose, white tail deer, and parasite.

Is there another interpretation for why c is incorrect?

[Adam Tyson]

The answer to a Resolve the Paradox question must address BOTH sides of the paradox, ameliakate. In the case of answer C, what do the habits of the wolves tell us about the declining population of moose in the first region? One might even think that the increase in deer would give the wolves there more opportunity to eat deer rather than moose, and the moose population might be expected to grow rather than decrease!

Aside from answer C's failure to address what's happening in the first region, the issue in the stimulus that must be addressed in the answer is that in one place, more deer has caused fewer moose, and in the other place more deer has NOT caused fewer moose. We know why the moose are declining in the first region - it's because of the parasites carried by the deer. What we need is an answer that tells us why that same effect is not present in the second region. Why aren't the moose there affected by the deer-borne parasite? That's the "paradox", if you can call it that, that needs to be addressed. Wolves in that region also eating rabbits and squirrels and elk doesn't explain why the moose aren't declining from the same parasite.

Be sure to address both sides of the paradox, and explain why both things can be simultaneously true and make sense. That's the kind of active resolution we need!

[kristinajohnson@berkeley.edu]

Shelton: The recent sharp decline in the number of moose in this region was caused by a large increase in the white-tailed deer population. While the deer do not compete with moose for food, they carry a dangerous parasite that can be transferred to any moose living nearby.

Russo: The neighboring region has also experienced a large increase in the white-tailed deer population, but the moose population there has remained stable.

(D) There is a large overlap in the ranges of moose and white-tailed deer in the region with the declining moose population, but not in the neighboring region.

(C) Wolf packs in the region with the declining moose population generally prey on only moose and deer, but in the neighboring region the wolf packs prey on a wider variety of species.

What is up with this practice test? Am I the only one missing two star problems like this one? What is going on? This answer choice totally didn't make sense in the moment! (D) must be saying moose and deer do hang out in the same area in "this region" but they do not hang out in the same area in "the neighboring region." For goodness sake! I read this under timed conditions as the regions overlap. Also, (C) looks good.

Thoughts? Reassurance? Solidarity?

[kristinajohnson@berkeley.edu]

Just to explain (C) looks good and seems to be considering both regions because if wolves prey on only moose and deer in the declining region but have a more diverse diet in the stable region then more moose and deer are disappearing in the former and less are disappearing in the latter. However, I do see what Adam is talking about in his post; that the paradox that needs to be addressed should more be about deer and parasites. Sometimes the resolution has nothing to do with what's going on in one statement or another, my bad.