BIOB51H3 Lecture Notes - Lecture 7: Swim Bladder, Alternative Hypothesis, Heritability
Document Summary
Slide 67: lungs allowed tetrapods to be on land. Slide 68: some fish have swim bladders and some have lungs. Slide 69: lungs and swim bladders came from same precursor cells. Fish appear before tetrapods: because fish appear earlier, maybe lungs evolved from swim bladders. Slide 70: most modern fish had swim bladder but most fishes had lungs! Slide 71: all had swim bladder but then some had swim bladder lost, some had lungs gained. Slide 72: alternative: ancestor of all these fishes had lungs, 2 lineages are different, the rest had traits from ancestors. Slide 73: o(cid:272)(cid:272)a(cid:373)"s razor is that the (cid:271)est e(cid:454)pla(cid:374)atio(cid:374) is the (cid:271)est o(cid:374)e with fewest assu(cid:373)ptio(cid:374)s, parsimony: deciding among alternative explanations based on minimizing the total amount of complexity required. Slide 76: parsimony hypothesis is correct, lungs actually went even further down the tree. Slide 77: use many methods to find out how evolutionary relationships went.
