Q16

[tzyc]

I think from the passage, how they form wings depends on temperature, so when it was unusually warm, it would form similar wings as in summer.
Is that why (A) is correct?
I actually chose (D), since the author says in summer they do not leave the ponds so I thought they may have similar habit in an unusually warm season.
Why is (D) incorrect?

[demetri.blaisdell]

This passage is pretty tricky. Lots of big words. This question is testing how well you understand the micropterous/macropterous idea. Bugs that hatch from cold eggs have micropterous wings don't work (the eggs are laid in fall, get cold over the winter, but hatch in the summer when the bugs don't need wings). Bugs that hatch from warm eggs have macropterous wings which do work (the eggs are laid in spring, stay warm over the summer, but hatch in the winter when the bugs do need wings). There is one more batch of eggs in late summer. All of these eggs stay warm so they hatch in to the overwintering generation (macropterous) which all have working wings. So to review:

Summer bugs are of two varieties:
a) Micropterous (hatched in fall, get cold in winter)
b) Macropterous (hatched in spring, don't get cold)

Overwintering bugs are all macropterous (hatched in late summer so they never get cold)

(A) gives us what we'd expect. If the winter is warm, then the eggs laid in the fall wouldn't get cold. Warm eggs create macropterous (working wings) bugs. So, unlike most years, the summer bugs would be able to fly.

The wrong answers:

(B) is the opposite of what we'd expect. There will be more working wings in the summer, not less.

(C) also seems unlikely. The eggs laid in the fall are affected by the temperature in the winter. There is no reason why they shouldn't be affected.

(D) is tempting. But the passage doesn't connect leaving the pond with the weather (see lines 27-30). It just says the overwintering generation goes to the forest. It's during the summer that the weather might affect behavior (when ponds dry up).

I hope this helps. Let me know if you have any questions.

Demetri

[BarryM800]

I'm really confused by this question. It relates to the overwintering generation and how an unusually warm weather in the winter months would affect their offsprings. I thought both (A) and (B) are talking about the wrong group - "eggs formed by water bugs in the autumn." Wouldn't they be the offsprings of the summer generation?

Line 45 points out that "[t]he dimorphism of micropterous and macropterous individuals in the summer generation expresses developmental flexibility; it is not genetically determined." Line 46 specifically states, "[t]he individual's wing form is environmentally determined by the temperature, to which developing eggs are exposed prior to their being laid." So how could the weather in the winter months affect the environmental temperature that eggs are exposed to in the autumn?

That's why I chose "(C), eggs of the overwintering generation formed in the autumn would not be affected by this temperature change." However, I do acknowledge that eggs of the overwintering generation would be formed in the spring, not the autumn. So in this sense, this answer choice doesn't make sense. Or am I missing something in this passage? Thanks!

[Misti Duvall]

I'm really confused by this question. It relates to the overwintering generation and how an unusually warm weather in the winter months would affect their offsprings. I thought both (A) and (B) are talking about the wrong group - "eggs formed by water bugs in the autumn." Wouldn't they be the offsprings of the summer generation?

Line 45 points out that "[t]he dimorphism of micropterous and macropterous individuals in the summer generation expresses developmental flexibility; it is not genetically determined." Line 46 specifically states, "[t]he individual's wing form is environmentally determined by the temperature, to which developing eggs are exposed prior to their being laid." So how could the weather in the winter months affect the environmental temperature that eggs are exposed to in the autumn?

That's why I chose "(C), eggs of the overwintering generation formed in the autumn would not be affected by this temperature change." However, I do acknowledge that eggs of the overwintering generation would be formed in the spring, not the autumn. So in this sense, this answer choice doesn't make sense. Or am I missing something in this passage? Thanks!

My understanding is that the summer generation is the overwintering generation, cause they hatch in summer and lay their eggs in the spring. The other generation lays eggs in the summer, then dies. I think what's tricky here might be the difference between when eggs are formed and when eggs are laid.

Hope this helps.