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15 Cards in this Set
- Front
- Back
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Morphospecies concept
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One of the 3 major concepts used to identify species by biologists. Involves using: physical characteristics or differences & very detailed measurements.
Disadvantages: there are a lot of physical differences within a species, different species without the ability to breed (convergent evolution) may look similar but they can breed. (biologists who support this say it is the same species anyways) |
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Advantages of the Morphospecies concept
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Advantages: data can be very easy to collect, fossil records (only way.
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Disadvantages of the Morphospecies concept
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Disadvantages: there are a lot of physical differences within a species, different species without the ability to breed (convergent evolution) may look similar but they can breed. (biologists who support this say it is the same species anyways)
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Biological species concept
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Developed by Earnst Mayr, defines species based on if they can breed and if they produce viable offspring.
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Disadvantages of Biological species concept
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Species don't live near each other, cant be used with fossils, microbes produce a-sexually, so doesn't help w/them.
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Phylogenetic species concept
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replaces(not completely) the other two species concepts, it looks at common characteristics in DNA to identify the common ancestor; there are several methods: neighbor-joining, maximum parsimony
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Advantages of Phylogenetic species concept
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Can be used for RECENT fossils, can be combined with morphospecies for fossils, use this very well in looking at microbes/used on all organisms (both biological and molecular)
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Disadvantages of Phylogenetic species concept
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based upon molecular data some scientists concerned too much emphasis on molecular approach. (need to make sure homologous sequences)
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monophyletic group
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(share a common ancestor) with the smallest diagnosable cluster of individuals exhibiting common ancestry.
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paraphyletic group
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include only some common ancestors & some descendents
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clade
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a taxon derived from a common ancestor
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node
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(where branches join) indicated a common ancestor
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sister taxa or clade
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are joined by nodes & are more closely related to each other than to any other taxa
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terminal taxa
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taxa at the ends of the branches
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Stage 1 of Speciation
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isolation of the gene pool: allopatry, sympatry, parapatry
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