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BIOL 202 DIVERSITY OF LIFE II Lecture 4 Vertebrate Transition to Land: Origins of Tetrapods
Readings/Figures •CHAPTER 18:Sec/on 18.4, Fig 18.22*, Box Fig 18.3•CHAPTER 19:Sec/on 19.1, Figs. 19.1, 19.2, 19.3**Revised from 8thedi/on, slide included here
2 major events of the Devonian**
mid mid Devonian – mid Permian (380-250 MYA) ØඏLand appears ØඏPeriods of local drought FIRST Land Vertebrates TETRAPODA
Figure 18.2 M & H FIG 18.2
Outline •What challenges do organisms face moving from an aquatic to terrestrial lifestyle? •What are the evolutionary linkages between Sarcopterygians, the Tetrapodomorpha, and the earliest Amphibians? •How did the vertebral axial and appendicular skeleton evolve for tetrapod locomotion?
Challenges moving from an aquatic to terrestrial lifestyle FEATURE CHALLENGE SOLUTION Increased light (1014photons/cm/s) & UV Surface protec/onAir less dense than water*Skeletal support, balance,locomo/on