Bio 142 chap 27 – Flashcards
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Which concept(s) for identifying species CANNOT be applied to asexual or fossil species?
answer
Biological species concept
The criterion of reproductive isolation cannot be evaluated in fossil species or species that reproduce asexually.
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Biological, morphological, and phylogenetic species concepts allow biologists to identify evolutionarily independent groups because they all rely on criteria indicative of _____.
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no gene flow between populations
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Many songbirds breed in North America in the spring and summer and then migrate to Central and South America in the fall. They spend the winter in these warmer areas, where they feed and prepare for the spring migration north and another breeding season. Two hypothetical species of sparrow, A and B, overwinter together in mixed flocks in Costa Rica. In spring, species A goes to the east coast of North America, and species B goes to the west coast. What can you say about the isolating mechanisms of these two species?
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Their winter habitat has no bearing on their degree of reproductive isolation.
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Imagine that you have data that shows that humans from a light-skinned population can exhibit greater similarity in DNA sequence with individuals from a dark-skinned population than with other individuals in the light-skinned population. Based on these hypothetical data, should these light- and dark-skinned human populations be considered separate species under the phylogenetic species concept? Why or why not?
answer
No. The DNA sequence data do not support the conclusion that they represent different clades.
According to the DNA sequence data, they are too similar to form separate branches on the tree of life.
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Which species concept would be most useful to a team of biologists conducting a biodiversity survey?
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The morphospecies concept.
The most common method for distinguishing species is on the basis of their appearance.
