PrepTest 157 - Section 4 - Passage 3 - Question 18

Hide analysis

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

Context · What's a "species"? Arguments about biodiversity assume we know this.

Debate among ornithologists · Lumpers vs. splitters

Lumpers group separate, but similar bird populations into a single species. Splitters divide those populations into different species.

Lumpers' perspective · Biological species concept

A species is a group that is reproductively isolated from other groups (not a lot of interbreeding in the wild between the groups).

Splitters' perspective · Phylogenetic species concept

A species is a population which has a pattern of ancestry and descent. Members of a species have a distinctive, genetically traceable feature.

Intro to Sibley · Part of splitters. Used DNA-DNA hybridization.

This technique compares DNA to determine relationships between different groups birds.

Sibley's perspective · Many earlier bird classifications were wrong

Examples: American vultures are more related to storks than European vultures. Loons and grebes aren't closely related.

One criticism of sibley (not by author) · DNA analysis still requires arbitrary interpretation

DNA shows differences between groups. But there's no clear line when those differences signify different species.

██████ █████ ███ ████ ██████████ ██ █████ ███ █████████ ██ ████ ██ █████ ████ ██████████ ████████ ███ ███████ ██ ███████ ███████████ ███████ ███████████ ██ ██████████ ████ ███ █████████ ████████ ██ ████ █████ ███ ██████ ██ ███████ ██ ██████ ██ ███████████ ██ ██████ ██ ██████ █████ ██ ███████████ ███ ████████ ███████████ ██ █████████ ██████████ █████ ██ ███████ █████████ ███ ███ ████████ ████████ ██ ████████ ███████ █████ ███ ██ ████ ████████ ██ ██████ ██ ███████████ ████ ██████ ██ ███ ███ ███████ ███ ██ ███████████ ███ ███████

Sibley's potential response · Acknowledges that "species concept" is slippery

However, for practical reasons, we have to limit the number of species we recognize. (If we said you were a different species from your mom, because you have slightly different DNA, that would lead to billions of different "species" in the world. That's impractical.)

Implications of debate · How we answer the species question has political and economic consequences

Example: Increasing number of species would likely increase number of endangered species.

Passage Style

Critique or debate

18.

Which one of the following ████ ██████████ ███████████ ███ ██████████ ███████ ████████ ██ █████████ ██ ███ ████████

Question Type

Application

This is an Application question. Here, we are looking for an example that illustrates the biological species concept, which is the theory used by lumpers. Those who use the biological species concept define a distinct species as a population that doesn’t interbreed with other populations in the wild. We are looking for an example that illustrates this definition accurately.

There is strong ████████ ████ ████ ███████████ █ ███ █ █████ █ ██████ █████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████ ████ ██████ ████ ██ ███ ████████ ████ █████ ██ ███████ █████████

It’s the phylogenetic species concept (used by splitters), not the biological species concept (used by lumpers) that cares about common ancestors. (A) doesn’t say whether or not populations X and Y reproduce with each other, so we don’t know how to classify them based on the biological species concept.

Bird populations X ███ █ ██████████ ██ ███ █████ ███ ████ ████ █████ ████ █████ ██ ██ ██ ██ ██████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ █████████ ████████

According to the biological species concept, a species is a group that is reproductively isolated from other groups. In (B), X and Y interbreed in the wild, so they’re not reproductively isolated from each other. Because of this, we should not classify them as different species under the biological species concept. (B) says that they should be classified as different species, so (B) doesn’t accurately apply the biological species concept.

Bird populations X ███ █ ███ ████████ █████████████████ ████ ████ █████ ███ ████ ██ ████████ ██████ ████████ █████████ █████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████

The biological species concept is about reproductive isolation, not about appearance. (C) doesn’t tell us if the two populations reproduce with each other, so we don’t know how to classify them according to the biological species concept.

13%

Although bird populations █ ███ █ ████ ███████████ ██████ █████ ███ ████ █████████ ████ ████████████ ███████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████

According to the biological species concept, a species is a group that is reproductively isolated from other groups. In the example in (D), populations X and Y are not reproductively isolated from each other, so they should be classified as belonging to the same species. (D) accurately applies the biological species concept.

63%

Although bird populations █ ███ █ ████ █████ ████ █████ ██ ███████████ ████ ████████ ████ █████ ██ ███████████ ███ ███████████ ██ █████ ███ █████████ █ ██████ █████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████

The biological species concept is about reproductive isolation, not about appearance. (E) says that the two populations have never been known to interbreed, so we should not classify them as the same species according to the biological species concept. Additionally, it’s the phylogenetic species concept (used by splitters), not the biological species concept (used by lumpers) that cares about common ancestors.

14%

PrepTest 157 - Section 4 - Passage 3 - Question 18

Difficulty

Analysis

Answer Popularity

Question history

Confirm action