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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
21.
It can be inferred from ███ ███████ ████ █ █████████ ██ ███ ██████████ ███████ ███████ █████ ██ ████ ██████ ██ ████████ ████ █████ ███ ██ ███ █████████ ███████████
a
There are considerably ████ ████ ███████ ██ ███ █████ █████ ████ ███ █████████ ███████████
b
Members of two ████ ███████████ ████ ██████ ████ ████ █████ ██ ███████ ████████ ███████████████ █████ ████████████ ██████ ██ ███ ████ ████████
c
Some animal species ████ ███ ██████████ ███████ ██ ████ ████ █████████ ████████
d
There is less ████████████ ██ ███ █████ █████ ████ █████ ███ ██ █████ ████
e
Current debates over ████ ███████████ █ ███████ ███ █████████ █████████ ██ █████████ ██████ ████ ██ ██████████ █████████