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15 Cards in this Set

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Morphospecies concept
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)
Advantages of the Morphospecies concept
Advantages: data can be very easy to collect, fossil records (only way.
Disadvantages of the Morphospecies concept
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)
Biological species concept
Developed by Earnst Mayr, defines species based on if they can breed and if they produce viable offspring.
Disadvantages of Biological species concept
Species don't live near each other, cant be used with fossils, microbes produce a-sexually, so doesn't help w/them.
Phylogenetic species concept
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
Advantages of Phylogenetic species concept
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)
Disadvantages of Phylogenetic species concept
based upon molecular data some scientists concerned too much emphasis on molecular approach. (need to make sure homologous sequences)
monophyletic group
(share a common ancestor) with the smallest diagnosable cluster of individuals exhibiting common ancestry.
paraphyletic group
include only some common ancestors & some descendents
clade
a taxon derived from a common ancestor
node
(where branches join) indicated a common ancestor
sister taxa or clade
are joined by nodes & are more closely related to each other than to any other taxa
terminal taxa
taxa at the ends of the branches
Stage 1 of Speciation
isolation of the gene pool: allopatry, sympatry, parapatry