BIOL 206 Lecture Notes - Lecture 29: Fetus, Book Lung, Melanesians

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13 Oct 2016

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Morphospecies- species identified based on morphological characteristics. Cryptic species- groups that are/were actually independent of one another appear to be members of the same species based on morphological characteristics. Phylogenetic species concept- species identified based by estimating the phylogeny of closely related populations and finding the smallest monophyletic groups. Biological species concept- species identified based on evolutionary independence by reproductive isolation. Species- the smallest evolutionary independent unit: gene flow, genetic drift, mate selection, act independently in different species. Speciation- the evolution of reproductive independence between populations. In organisms that reproduce sexually, speciation requires an interruption in gene flow between populations. Just since different populations of boobies have different bill colours, they do not recognize each other as potential reproductive partners. Same in morphology, anatomy, and everything else: gene flow is rare because of conjugation, the recipient can start adapting to a new habitat and then it can form a new species.

Related Questions

4. The shovel-nosed salamander, Desmognathus marmoratus, is a totally aquatic, endemic species found in high mountain streams in the Appalachian Mountains of Tennessee, North Carolina, South Carolina and Georgia. No gene flow occurs between river drainages due to the completely aquatic lifestyle of this salamander. Populations on either side of the Tennessee Divide (Tennessee and N. Carolina vs. Georgia and S. Carolina) have no morphological differences between them. A phylogeny based on mtDNA sequences (Jones et al. 2006) showed, however, that populations on either side of the Tennessee Divide showed greater than 14% sequence divergence and were well supported, separate, monophyletic lineages. Salamanders collected from drainages on both sides of the Tennessee Divide were brought into the laboratory and observations confirmed that salamanders from Tennessee would mate with salamanders from Georgia and made viable and fertile F1 and F2 offspring. Based upon your understanding of different species concepts (biological, morphospecies, phylogenetic), how would each classify these shovel-nosed salamanders (i.e., separate species or the same species, and why?). Under which type/mode of speciation are these salamanders likely to be diverging on opposite sides of the Tennessee Divide?

4. The shovel-nosed salamander, Desmognathus marmoratus, is a totally aquatic, endemic species found in high mountain streams in the Appalachian Mountains of Tennessee, North Carolina, South Carolina and Georgia. No gene flow occurs between river drainages due to the completely aquatic lifestyle of this salamander. Populations on either side of the Tennessee Divide (Tennessee and N. Carolina vs. Georgia and S. Carolina) have no morphological differences between them. A phylogeny based on mtDNA sequences (Jones et al. 2006) showed, however, that populations on either side of the Tennessee Divide showed greater than 14% sequence divergence and were well supported, separate, monophyletic lineages. Salamanders collected from drainages on both sides of the Tennessee Divide were brought into the laboratory and observations confirmed that salamanders from Tennessee would mate with salamanders from Georgia and made viable and fertile F1 and F2 offspring. Based upon your understanding of different species concepts (biological, morphospecies, phylogenetic), how would each classify these shovel-nosed salamanders (i.e., separate species or the same species, and why?). Under which type/mode of speciation are these salamanders likely to be diverging on opposite sides of the Tennessee Divide?

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BIOL 206 Lecture Notes - Lecture 29: Fetus, Book Lung, Melanesians

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