Reading Comprehension

PT157 · S4 · P3 · Q18 Definition of Species

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Political arguments about biodiversity and the preservation of endangered species generally assume we know what a species is.

Topic

The challenge and controversy of defining what counts as a "species," especially in ornithology, and the implications of different definitions.

Framework

Present Debate

Main Point

There is an ongoing debate among scientists about how to define a species, with significant practical and political consequences, especially for conservation. ( — opening sentences, and the summary of practical stakes at the end.)

P1: Debate Over What Constitutes a Species

This paragraph introduces the ongoing debate about what a "species" actually is, focusing on the classic divide between "lumpers" (who group similar populations) and "splitters" (who separate populations into more species). Lumpers use the biological species concept (reproductive isolation), while splitters prefer the phylogenetic species concept (diagnosable populations with unique, genetically traceable traits).

P2: Example of a "Splitter" – Sibley's Contributions

Here we get an example in ornithology: Charles G. Sibley, a splitter, used DNA technology to challenge conventional classifications of bird species, arguing for unexpected relationships among birds (like American vultures being closer to storks than to other vultures).

P3: Pushback and the Limits of Classification

Sibley's ideas faced significant criticism. A critic argues that interpreting genetic differences is arbitrary, and even Sibley concedes that species definitions are inherently slippery because many populations don’t fit our tidy definitions.

18.

Which one of the following most accurately illustrates the biological species concept, as described in the passage?

  1. There is strong evidence that

    Wrong Emphasis

    Since this answer doesn't mention interbreeding at all, we wouldn't be able to apply the biological species concept.

    4% picked this

  2. Bird populations X and Y

    Contradiction

    We were looking for one or the other of these two situations, but this is giving us a combo. 1. two groups of animals do interbreed, and thus they are same species 2. two groups of animals don't interbreed, an thus they are different species

    6% picked this

  3. Bird populations X and Y

    Wrong Emphasis

    Since this answer doesn't mention interbreeding at all, we wouldn't be able to apply the biological species concept.

    17% picked this

  4. Correct

    Although bird populations X and

    Why this is right

    We were looking for one or the other of these two situations, and this gives us the first one. 1. two groups of animals do interbreed, and thus they are same species 2. two groups of animals don't interbreed, an thus they are different species

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

    59% picked this

  5. Although bird populations X and

    Wrong Emphasis

    We were looking for one or the other of these two situations, but this is giving us a combo. 1. two groups of animals do interbreed, and thus they are same species 2. two groups of animals don't interbreed, an thus they are different species

    14% picked this

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