#12 - Populations of a shrimp species at eleven different

[mN2mmvf]

Why not (E)? If the shrimp are just getting pushed out into the ocean, how are they interbreeding with other shrimp?

[Adam Tyson]

The problem with E, mN2mmvf, is that while it might explain something less than a total interbreeding of the different shrimp populations, it doesn't do anything to help explain why the ones that probably do get to other reefs don't end up interbreeding and creating a more homogeneous genetic population. Okay, fine, so many of the shrimp end up in the open ocean, but couldn't there still be many more, even a majority, that end up at other reefs? The stimulus says they probably do, and in a classic Resolve scenario we don't want to deny either side of the paradox, but instead bring the two sides together. That is, we want an answer that says "sure, they get carried to other reefs, but the different reefs could still end up genetically distinct from each other". Answer E doesn't do that, but instead essentially denies the claim made by the author that the currents probably carry baby shrimp to other reefs. That's a typical wrong answer to a Resolve question - do not deny the facts as given, but instead just add new facts that allow those original facts to coexist.

Keep on pounding!

[mN2mmvf]

Thanks! I missed the "many." But even if I hadn't missed that, a good reminder to try to explain both sides of the paradox instead of deny its basis.

[harvoolio]

I prephrased the wrong answer based upon the word "interbreed" - "breed or cause to breed with another of a different race or species." (https://en.oxforddictionaries.com/definition/interbreed)

I thought if the shrimp interbred with another species (e.g. wolves and dogs) at the reefs that would explain the big genetic differences. So (B) seemed to confirm this.

[Daniel Stern]

In the stimulus, the shrimp are potentially interbreeding with other populations of shrimp at the other reefs, not necessarily with other distinct species of animal. I believe, and more importantly, LSAC believes, that this is an acceptable use of the term "interbreed" despite the dictionary definition that you cite. I guess technically the shrimp at the other reef

The problem with answer choice B is that it denies facts that constitute a portion of the stimulus. B posits that the shrimp have genetic variance as individuals within their population; but the stimulus said that the genetics only vary from population to population at different reefs. Our credited Resolve the Paradox answer is always going to explain both sides and allow the facts to exist as stated in the stimulus. The answer will never deny or cancel out stimulus facts, or "erase" one side of the discrepancy.

Best,
Dan

[harvoolio]

Thanks Dan.

[akanshalsat]

To explain this to myself (after getting it wrong and choosing B) I would say to picture it in the case of groups of marbles being the "population"

There is a group of blue marbles (population 1 = coral reef 1), group of red marbles (population 2 = coral reef 2)

In each group - in the beginning, there is only THAT color present which is the characteristic color of that coral reef. The stimulus is saying that since the ocean current MOVES these marbles between different reefs (groups) there should be more of a mixture or red/blue in each different group so as to say that the two groups become almost indistinguishable (bc they're all mixing)

C says that the shrimp (or the marble) RETURNS to its OWN population before breeding (so a blue marble that got washed away into the red group, actually GOES BACK to its own group) --> this then allows for the CONSISTENT difference between the two groups despite the "mixing" and "movement"

B is wrong bc it talks about the differences WITHIN a SPECIFIC population - for example - it talks about the fact that blue marble A is different from blue marble B slightly - but this is just talking about the differences in marbles SIMPLY in group 1 (blue marbles) and doesn't discuss why the blue marbles are different from the red marbles (the difference between the two populations)

Sorry if this is longwinded and slightly confusing, I'm just trying to write it out to explain it to myself!

[Malila Robinson]

Hi akanshalsat,
Your reasoning is valid! Great job working through a tough problem!
-Malila