Tiger beetles are such fast runners - CR

[yqren2002]

i think the idea is that if fatigue were an issue, the beetles would get more fatigued going up an incline than going down, thus the length of pauses would be different. hence the fact that the pauses are the same undermines the hypothesis..

Thanks for explanation. I think we do need a little "imagination" to beat this problem :)

If it is a heavy beetle, it will be more obvious for me to rule out C.

[tim]

:)

[manhhiep2509]

Hello.
The problem is the question 25 in diagnostic test in OG 13. I tried to explain the choice B. Please take a look and see whether I am correct.

the choice says:

(1) when pursuing a changing-direction-constantly insect, the beetle change its course.
(2) when pursuing a changing-direction-constantly insect, it stop more increasingly.

I think that (1) and (2) are two events happening simultaneously. The choice is trying to says that "the beetle change its direction and also stop, so it seems that the changing direction may have some connection with the pause."

The second hypothesis says the beetle stops because it cannot process all changing visual information. The choice gives a situation in which the beetle often has to process new visual information and also the phenomenon happens. As a result, I find the choice strengthen the second hypothesis.

Even though the choice B does not weaken the first hypothesis as the question stem requires, it is the only one choice at least strengthen a hypothesis. So B is correct.

Thank you.

[RonPurewal]

That answer choice specifically states that the beetle changes its course while running. Not when it's stopped.

The second hypotheses is weakened. If the beetle can alter its course while running, then it clearly must be able to process visual information. (Otherwise, it wouldn't know how to change its course!)

The first hypothesis is strengthened, because animals, like humans, get tired faster when they've been doing something for a while.

[peterm35]

(C) The beetles maintain a fixed time interval between pauses, although when an insect that had
been stationary begins to flee, the beetle increases its speed after its next pause.

Hi there,
I have a question about C. The forum posts are confusing on this problem as there appear to be two versions of the question floating around. In the newer version of C that I posted above...

It seems as though this is the correct answer. First, common sense dictates that if something or someone is running and pauses at fixed intervals regardless of how long or how fast it/he she has been running, fatigue must NOT be a factor.

Also, if the beetle does not increase its speed of pursuit until AFTER its next pause, it implies that the beetle did not observe the preys change in behavior until it had stopped. In other words, it was unable to see it until during the break.

This seems to clearly undermine the fatigue theory while at the same time support the blindness theory.
Thanks!
Peter

[RonPurewal]

In whatever version you're looking at, what is cited as the correct answer?

The constant running intervals, by themselves, don't necessarily undermine the fatigue hypothesis; it's possible that they are a way of averting fatigue, if the intervals are shorter than the time it would take to reach fatigue. (E.g., if I had to finish a marathon, I'd run fixed distances and then stop to walk. I wouldn't run until I was absolutely exhausted and only then start to walk.)

The fact that the intervals are still fixed despite differences in speed, though, does seem to discredit the fatigue hypothesis.

[RonPurewal]

What's most interesting about this problem is how bad the OG's explanation is (for the version that's in the OG, which is not the one you're talking about).

A different version of the problem appears as #25 in the OG diagnostic chapter.
The answer key "explains" the correct answer in exactly the opposite of the actual explanation. In that problem, the correct answer supports the fatigue hypothesis and undermines the blindness hypothesis—but the "explanation" says the opposite (!!).

Ah, the joys of outsourcing answer explanations to cheaper labor (yes, this is what the OG does).
At least you can trust the problems and answers, though.

[Crisc419]

sorry for bumping this thread up again.

i can't understand this sentence, what this sentence is talking about,especially understand the underlined part

(C) The beetles maintain a fixed time interval between pauses,although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.

could you explain this sentence ? and tell me how it weaken one and strengthen the other?

Thanks in advance.

Cris

[RonPurewal]

when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.

—> if a prey insect was previously standing still, but has started running away, the beetle will speed up to try to catch it.

this would work AGAINST the "getting tired" hypothesis, because, if that hypothesis were correct, the time intervals wouldn't be fixed—the beetle would have to stop more often if it were running faster.

it works in favor of the "temporarily blind" hypothesis, because the beetle doesn't speed up until after the next pause.

[Meerak869]

Can someone please explain Why option b is correct.

I agree the course alternation indicates support for theory 2 of changing visual information.

But how does that undermine theory 1 regarding regarding pace and pause for rest.

[RonPurewal]

Can someone please explain Why option b is correct.

I agree the course alternation indicates support for theory 2 of changing visual information.

But how does that undermine theory 1 regarding regarding pace and pause for rest.

should be the other way around -- if the beetle can change directions WHILE RUNNING, then the "temporary blindness" hypothesis must be incorrect. (if the beetle were temporarily blind, it wouldn't know which direction to change toward!)
on the other hand, this evidence seems to support the "fatigue" hypothesis, because ... this is just how fatigue works, in general. the longer a creature runs, the more breaks it needs... whether that creature is a human, an insect, a horse, or some other animal.

so, supports #1, basically disproves #2.