#19 - A recent study examined the daytime and nighttime

[Administrator]

Complete Question Explanation

Resolve the Paradox. The correct answer choice is (B).

Answer choice (A):

Answer choice (B): This is the correct answer choice.

Answer choice (C):

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

[amacmill]

I'm confused about this one because it seems to me that you'd need to make the assumption that birds can't see the lemurs while they're asleep during the day, and I didn't thing that was an okay assumption to make.

[nicholaspavic]

Hi amac,

This is a Resolve the Paradox Question where we a searching for a possible cause of the situation. The stimulus does not offer us information one way or another on whether the birds can spot the the deciduous lemurs while they are asleep in the trees. Perhaps they sleep in holes in the trees or camoflauged nests? But we don't know one way or another from the facts presented in the stimulus.

What we do know is that their activity when they are awake in the trees could leave them exposed to these types of flying predators which is why Answer (B) is a great cause to explain why the deciduous-dwelling lemurs go to more nocturnal behavior during those winter months, when their rainforest counterparts still get protection from the canopy in the winter. Answer Option (A), which is a favorite wrong answer choice for students, applies to both types of lemurs and does not offer an explanation as to why the deciduous lemurs behave differently in the winter months.

Thanks for the great question!

[jmramon]

Hi Powerscore,

I sort of get why B could be right, although I think it requires too many extra assumptions to understand why it could resolve the paradox (for example, that activity as opposed to sleep during predatory hours makes the deciduous lemurs more vulnerable in the daylight due to lack of tree cover in winter months). How does one come to this answer without extra assumptions? I would think that sleeping in the poorly covered trees during the peak time for these birds hunting would be most dangerous for the deciduous lemurs b/c they aren't aware of their surroundings.

[Adam Tyson]

Sounds to me like you're making some questionable assumptions yourself, jmramon! Where do we get the idea that lemurs are not aware of their surroundings when they sleep? Maybe they plan their sleeping spots carefully to make sure they have the best possible cover, like under a big branch? And who says they can be seen during the day in deciduous forests? Many trees lose their leaves, but that doesn't necessarily mean all, so maybe they are sleeping under the few leaves that remain, hidden away from flying eyes?

The issue that trips up a lot of people on this one is that they focus on the wrong comparison. It's not that lemurs in deciduous forests are more active at night than those in rain forests with good canopy cover; it's that their change from daytime to nighttime is more pronounced. Think of it as a change in percentage of activity, rather than being about a total amount of activity. That could mean that they get really active at night, or it could mean that they are much more still during the day. Anything that explains either of those things - anything that explains why their shift from day to night is so much bigger than the same shift by lemurs in the rain forests - will help.

Answer B gives us a reason why the deciduous forest lemurs might be relatively still during the day. Staying still might be a way to avoid notice by predators. Moving around means getting seen more easily! So, they stay still during the day, perhaps hidden under branches and leaves or perhaps just holding still so as to attract less attention, and then at night they get moving - big change. Meanwhile, in the covered rain forests, lemurs move during the day, less concerned about being spotted from above since they have cover and camouflage, and they keep moving at night - small change. Boom - paradox resolved!

We know, based on the premises, that those lemurs with less cover are definitely less active during the day than they are at night, and that their change from day to night is, relative to the other lemurs, a bigger change. It's not that much of a leap to assume that when you have less cover, staying hidden (or at least holding very, very still) is a better way to avoid predators than moving around. B is the only answer that could explain the relatively large difference in daytime and nighttime activity of those lemurs, and thus is the best answer and the credited response.

I hope that helps clarify it! I know this one causes a lot of confusion.

[McHenrytest]

Hello, so I got this one right, but it was basically a coin flip between B and E. I assumed both of these options have no effect on the rain forest lemurs (any winter uptick in activity would be natural for lemurs) so there's no difference there. And then, if the deciduous lemurs eat plants (trees lose their leaves), they would have to a lot more active in the winter months because there were less plants available. I chose B because it addressed the daylight/nocturnal issue directly, but I'm looking for a more concrete reason that E could be ruled out. Thanks.

[nicholaspavic]

Hi McHenry,

I think your problem is coming in with the concept of diurnal vs nocturnal activity for "plants." (Hey! I just diurnal in a sentence. My Biology teacher would be so proud!) So anyway, you have already noted that Answer Choice B directly addresses that difference, but what is really going on in E? It would appear to me that perhaps you are misreading the stimulus for the implication that these lemurs are eating tree leaves and not other "plants," but that's not what it is saying. It's only saying that the deciduous lemurs increase nocturnal behavior in the winter months and not that they don't have access to as much food as they normally have.

This is a tricky one! Thanks for the great question.

[jmramon]

Thank you, Adam! Your explanation helped me a lot!

[chian9010]

Could anyone tell me why answer choice C is incorrect?
I feel like if predator snakes are more active during daylight in winter, then it is reasonable for tree-dwelling lemur in a deciduous forest to stay still to be safe and go out more at night. However, since the lemur in rain forest have leaves to cover them, they don't worry too much about safety during the winter time.

[Who Ray]

Hi Chian!

It is interesting that you are using the same reasoning for both predators. However, because AC B mentions that the predatory birds need to use day time vision, it is a better choice. The snakes might use smell or sound or infrared vision which do not rely on light at all, so your assumption that the lemurs sit still or hide during the day from snakes might not make sense. Sitting still might be the worst thing to do because the slow snake could creep toward the still lemur. However, with AC B we do not have to mess with any of these hypotheticals.

Cheers,
Who Ray