BIO SCI 100 Lecture Notes - Lecture 6: Flowering Plant, Extinction Event, Cambrian Explosion
19 Apr 2017
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Other evidence of evolution: comparative anatomy, embryology, biogeography, molecular biology. All vertebrates have pharyngeal pouches: homologous: fish -> gills, human and mammals -> eustachian tubes that connect to m. ear and throat. 3. study of geography distribution of species and populations. Species tend to be more closely related to those from nearby places. 4. universal code: all lifeform share certain molecular trait. Molecular analyze usually conform previous conclusion coherence can use molecular homologies when other approaches insufficient. Geologic time scale of earth: eras, period, epochs. Each ear, period, epoch covers a series of major events, then punctuated by a catastrophic event. Isoceans followed by origins of life: 3. 8-4 bya. Permian extinction (biggest extinction) 70-90% of life from extinct 250 mya. World maps looks familiar 20 mya. Hominids 5-7 mya (spit from common ancestor with chimpanzees) Mass extinction: catastrophic events that wipe out large numbers of species. At least 60% wiped out in a million years, result from periodic fluctuation.
