Definition of Species

Answer choices

1. A

   Out of Scope2% picked this

   Splitters are somewhat more likely than lumpers to be motivated by political and economic, rather

   The idea of political / economic concerns comes from the final paragraph. It's not reinforcing any of the details we have about Sibley in the 2nd and 3rd paragraphs. And the passage provides no evidence for the idea that one group is more politically / economically motivated than the other group.

   2%
2. B

   Contradicted1% picked this

   The total number of animal species in the world today is

   Since Lumpers have been in charge thus far (the dominant approach to categorization), and since Splitters want to take some of these populations that are lumped together as one species and split them up according to genetic differences, the Splitters would create a world with a bigger number of species if they had their way.

   1%
3. C

   Contradicted19% picked this

   A proper goal for ornithologists engaged in taxonomic research is to simplify the classification system so as to reduce

   Just like (B), this is the opposite of what a Splitter would say. The goal of a Splitter like Sibley is to actually increase the number of species, because they want to take an animal population that is currently being lumped together as 1 species and split it up into multiple species. Their system is less simple than Lumpers'. Lumpers just ask whether or not two populations interbreed frequently in the wild. Splitters have to study the DNA of populations and compare them.

   19%
4. D

   Contradicted18% picked this

   The degree of genetic difference that two populations display with respect to each other should have little bearing on the decision about whether to

   Sibley is a Splitter and splitters specifically use the degree of genetic difference that two populations display with respect to each other, in order to help determine whether or not they should be considered to belong to the same species.

   18%
5. E

   Correct60% picked this

   Disagreements about species classification are likely to persist even if techniques like DNA-DNA hybridization

   Why this is right

   This builds off Sibley's concessions in the 3rd paragraph, where he says that "the species concept is slippery because there are so many examples in nature of populations that refuse to fit our limited set of definitions and names". Earlier in that paragraph the author suggests that Sibley would also agree, at least in part, to the notion that DNA-DNA can give you an approximation of how different two animals' sets of genes are from each other, "but how you interpret those differences is basically arbitrary". An arbitrary interpretation or a decision made on a somewhat arbitrary basis is likely to have people who disagree with it. If someone were to disagree with this answer, they would say, "Nuh-uh ... if techniques like DNA-DNA hybridization are further refined, it will be unlikely for there to be any disagreements about species classification". That's a pretty implausible position, that disagreements about species classification will just stop entirely. So agreeing that disagreements will still take place, even in an improved future, is a very safe idea.

   Skill tested: Non-Author Opinion · how this choice captures the passage's function is the move to repeat next time.

   60%