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passage 3
P1
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.
P2
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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.
P3
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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.)
P4
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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
15.
Which one of the following ████ ██████████ █████████ ███ ████ █████ ██ ███ ████████
a
Classifying biological populations ████ █████████ ███████ ███ ████ █████ ████████ ███ ██████████ ██ █████████████ ███ ████ ██ █████ ████████ ███ ██████ ██ ██████████ ██████ ██ ███ ████ ██ ███████ ██ ██████ ███ ███████
b
Although scientists often ████████ ██ ███ ██████████████ ██ ██████████ ███████████ ████ ████████ ████ █████ ████ ███ ████ ██████████████ ███████ ███████ █████████ █████████
c
How biological populations ███ ██████████ ████ ███████ ██ █ █████████████ ██████████ █████ ████ █████████ ████████████ ██ ███████ ███████ ████ ███ ████████████ ██ █████████████
d
Traditional methods of ███████████ ██████████ ███████████ ████ ███████ ████████ ██ ████ █████ ███████████ ███ █████ ███████ ████ ████ ██████ ████ ████████ ██ ███ ████ ██ ███████ ██ ███████
e
Charles G. Sibley █████████ █████████████ ███████ ██ ███████████ ██████████ ███████████ ████ ████████ ███ █████ ███████ ████ ███ ████ ██████ █████████