BIOS 390 Exam 4 - –Answer classifying species based on morpholo...

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BIOS 390 Exam 4

• strengths and weaknesses of morphospecies

–Answer classifying species based on morphological distinctions between related species

• cheap, observational, works for living and extinct species
• difficult to apply to all organisms

-cryptic species

• strengths and weaknesses of phylogenetic species

–Answer species are identified by estimating their phylogenetic trees by finding smallest monophyletic groups

• works for extinct/living, works for sexual/asexual and cryptic, testable
• differing sources lead to differing trees
• strengths and weaknesses of biological species

–Answer species are evolutionarily independent once they are reproductively isolated

• meaningful criterion because there is a lack of gene flow
• difficult to test, cannot use for asexual, cant be used for extinct
• ways that populations and species can be isolated

–Answer allopatric speciation –Answer geographic isolation from dispersal (one population leaves) or vicariance (split by some new geographic formations) sympatry –Answer speciation despite living in the same place due to chromosomal changes, differences in reproductive timing, differences in pollinators 1 / 2

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• mutations that physically prevent mating
• evidence that can provide insight into how certain lineages were separat- ed

–Answer allopatry- dispersal –Answer Hawaiian fruit flies

• many species are found on one island
• species closely realted found on neighboring islands and sequence of branching events

corresponds with island formation allopatry- vicariance –Answer snapping shrimp

• the species began separating due to the isthmus of panama
• oldest separations lower in the water column, and sister species are seen for one species

(A,B,C) on either side of the barrier sympatry- mutations –Answer snails

• the coiling of the shell (right or left) was a mutation that physically prevented mating based on

shell coiling leading to two species

• natural selection in different environments produced divergences

–Answer yellow monkeyflowers

• two distinct ecotypes and they were planted in each others ecotype
• saw that the native flower has significantly higher fitness than the non-native
• natural selection and assortative mating producing divergence

–Answer strawberry poison dart frogs

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