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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
18.
Which one of the following ████ ██████████ ███████████ ███ ██████████ ███████ ████████ ██ █████████ ██ ███ ████████
a
There is strong ████████ ████ ████ ███████████ █ ███ █ █████ █ ██████ █████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████ ████ ██████ ████ ██ ███ ████████ ████ █████ ██ ███████ █████████
b
Bird populations X ███ █ ██████████ ██ ███ █████ ███ ████ ████ █████ ████ █████ ██ ██ ██ ██ ██████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ █████████ ████████
c
Bird populations X ███ █ ███ ████████ █████████████████ ████ ████ █████ ███ ████ ██ ████████ ██████ ████████ █████████ █████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████
d
Although bird populations █ ███ █ ████ ███████████ ██████ █████ ███ ████ █████████ ████ ████████████ ███████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████
e
Although bird populations █ ███ █ ████ █████ ████ █████ ██ ███████████ ████ ████████ ████ █████ ██ ███████████ ███ ███████████ ██ █████ ███ █████████ █ ██████ █████████ ██████████ ████ ██████ ██ ██████████ ██ █████████ ██ ███ ████ ████████