Question

9. Below is a phylogeny of tern species. This is based on mitochondrial DNA sequences and comes from a paper by Brige et al (2005). White crown White blaze Black cap S. sumatrana and S. trudeani both have white head coloration. According to this phylogeny, is this a case of homology or analogy? Why? 5 points Gygis alba and A. tenuirostris also have white head coloration. According to this phylogeny, is this a case of homology or analogy? 5 points Why? a. b. Sterna dougalii S. striata S. sumatrana S. hirundinacea S. vittata S. paradisidae S. hirundo S. forsteri S. trudeaui S. bengalensis S. maxima S. bergii S. sandvicensis a S. sandvicensis e. S. elegans Chlidonias niger C. leucopterus C. albostriatus C. hybridus Larosterna inca S. caspia S. nilotica Phaetusa simplex S. albifrons S. nereis S. antillarum S. supercilliaris S. anaethetus S. lunata S. fuscata S. aleutica Gygis alba Anous minutus A. tenuirostris A. stolidus Larus delawarensis 10 Millions of years before present

Answer 1

a. S. sumatrana and S. trudeani both have white head coloration and according to this phylogeny, this is a case of analogy because both of the organisms have similar physical features because of environmental factors and there no role of close evolutionary relationship.

b. Gygis alba and A. tenuirostris also have white head coloration and according to this phylogeny, this is the case of homology because both organisms have similar physical features and evolutionary-based developmental similarities.