BIOL 1001 Lecture Notes - Lecture 24: Ichthyosaur, Marsupial, Phenetics

• School: York University
• Department: Biology
• Course: BIOL 1001
• Professor: Alexander Mills

Document Summary

Biol 1001 more on phylogenies: distinguishing homology from homoplasy, convergent evolution occurs when natural selection favors similar solutions to the problems posed by a similar way of life, convergent evolution is a common cause of homoplasy. Marsupial mammal (shares more recent ancestry with kangaroos, for instance) Placental mammal (shares more recent ancestry with dogs, e. t. c. : this is an example of phenotypic convergence: The dolphin (common dolphin) on the left is a placental mammal while the reptile on the right (ichthyosaur) which means fish lizard: the orange line represents two different groups with similar forms which both have terrestrial ancestors. 1 present in organism, 0 absent in organism. 0s are ancestral traits (old) and 1s are derived traits (apomorphies) Phenetics give equal weight to both 0s and 1s. 2: e. g. rivet and nail share 6 0s and 1s. Cladistics give equal weight to 1s only (synapomorphies: only compares derived traits.