Ch 25 - The history of life on earth (1 slide per page)-2

New evolutionary innovations 1prevent dehydration

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Unformatted text preview: Land Plants ~ 500 mya What facilitated colonization of land by plants? New evolutionary Innovations: 1.prevent dehydration 2.Move resources obtained from air and soil throughout plant 3.Support 4.Reproduction w/o H2O Key Events: 52 7. Colonization of Land Tetrapods ~ 360 mya What facilitated colonization of land by amphibians? • Many new evolutionary Innovations: 1.Lungs 2.Legs Ichthyostega Salamanders Amphiuma Lungfish Frogs Caecilian 53 Processes determining the rise and fall of groups of organisms 1. Adaptive Radiation 2. Continental Drift 3. Mass Extinction 54 Adaptive Radiation: A “burst” of speciation in a lineage common ancestor many daughter species with different adaptations Example: Hawaiian honeycreepers ~40 species descended from finch-like ancestor 55 What Causes Adaptive Radiation? 1. Ecological opportunity 2. New adaptations can lead to morphological innovation 56 What Causes Adaptive Radiation? 1. Ecological opportunity - Extinction of other species leads to previously unavailable opportunities Example: Mammals Terrestrial dinosaurs extinct ~65 mya following extinction of terrestrial dinosaurs mammals diversified 57 What Causes Adaptive Radiation? 1. Ecological opportunity - Extinction of other species leads to previously unavailable opportunities - Colonization of areas with: - unexploited opportunities - no competitors Anolis lizards colonizing Anolis free islands led to adaptive radiations 59 What Causes Adaptive Radiation? 1. Ecological opportunity 2. New adaptations can lead to morphological innovation - How do new adaptations arise? - Modified versions of older structures - Developmental gene...
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