Reading Comprehension

PT157 · S4 · P3 · Q21 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.

21.

It can be inferred from the passage that a proponent of the biological species concept would be most likely to disagree with which one of the following statements?

Correct
There are considerably more bird
Why this is right
This really just gets to the heart of Lumpers, who lump stuff together into one species, vs. Splitters, who split stuff up into multiple species. A world run by Splitters has more species than a world run by Lumpers. Until recently, Lumpers have run the world (i.e. they had the dominant approach to species classification). So, assuming they think they're doing a good job, they would think that the current number of recognized bird species is about right. Splitters, who want to take certain species and split them up into multiple species, would agree with this answer. They think it's crazy that we're lumping together Species X, when it's really three different species, X1, X2, and X3. Lumpers would disagree. "Stop it, Splitters. You're going to make there be too many bird species. The currently recognized number is good."
Skill tested: Non-Author Opinion · how this choice captures the passage's function is the move to repeat next time.
49% picked this
Members of two bird populations
Unsupported
A Splitter wants to split up population groups that have distinctive, traceable features. Lumpers will lump them all into the same species, as long as they interbreed in the wild. So a Lumper will agree that "even if two bird populations differ in physical characteristics, they might still belong to the same species (if they interbreed)."
28% picked this
Some animal species that are
Out of Scope
If we disagree with this claim, we're saying "That's not true. There aren't any species considered extinct that still have surviving members." That would be a very strong claim. We have no support for such a categorical denial. We only have those two sentences in the first paragraph that tell us about Lumpers, and neither one would let us support, "Every single species considered extinct is in fact extinct."
10% picked this
There is less biodiversity in
Out of Scope
We know almost nothing about Lumpers other than that they've been the dominant classification approach until recently, and that they define species based on whether or not populations interbreed. We have no idea how they feel about whether biodiversity has changed over the past 50 years.
8% picked this
Current debates over what constitutes
Out of Scope
We know almost nothing about Lumpers other than that they've been the dominant classification approach until recently, and that they define species based on whether or not populations interbreed. We have no idea how they feel about what motivates current debates. But since this answer is only saying debates are sometimes motivated by X, to disagree with this claim would be saying, "Current debates are never motivated by political concerns". We definitely can't support such an extreme position.
5% picked this

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