Lecture 2 Notes PDF
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These lecture notes cover the evolution of animal physiology, including constraints, evolutionary history, environmental pressures, and physiological regulation. The notes also include discussion points related to different time scales and the differences between water and air environments, and some examples in different environments.
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2025-01-06 Lecture 2: 8 Jan. Evolution of Animal Physiology constraints evol. history environmental pressures & diversity Physiological regulation, patterns &...
2025-01-06 Lecture 2: 8 Jan. Evolution of Animal Physiology constraints evol. history environmental pressures & diversity Physiological regulation, patterns & time scales Reading: 172-173, back inside cover, 20-25, 612-613, 602-604, 12-19, Boxes 1.1 (15), 10.3 (268) 1 1 2025-01-06 Evolution of Physiology influenced and constrained by: 1. Chemistry & Physics esp. thermodynamics Energy availability & efficiency of use 2. Evolutionary history 3. Selective Pressures esp. environmental 2 2 2025-01-06 Physiology & Thermodynamics Water Internal 19oC 31oC 300 mOsM; term? 1050 mOsM what would 2nd law of thermodynamics tend to do to animal temp., osmolarity? how do tuna seem to defy thermodynamic laws? physiology and biochemistry use chemical energy! 3 3 2025-01-06 Origins of Animal Life Origin of life Origin of earth 4 4 2025-01-06 In what 3 major media do animals live? 1. (hint; where animals first evolved) 2. (hint; where vertebrates likely first evolved) 3. (hint; where do you live?) 5 5 2025-01-06 Water-Air Transition 6 6 2025-01-06 Water-to-Air Transition: Vertebrates. 7 7 2025-01-06 Environments Change Over Time 8 8 2025-01-06 Air vs. Water: Physical Properties Property Water (distilled) Air Thermal Capacity 1.00 0.0003 Sound Velocity 1485 343 Refractive Index 1.33 1.00 Density 998 1.2 Viscosity 1.0 0.02 air: low density, viscosity and high gas diffusion: consequences? easy mixing (wind), so air composition virtually uniform around the world – exceptions: microhabitats e.g. burrows 9 9 2025-01-06 Environments Change Over Time Amazon River dissolved O2 Time of Day 10 10 2025-01-06 Temporal Diversity differences at one point in space over a given time scale On what predictable time scales will environmental parameters vary? Daily (diurnal) Seasonal/Annual Semi-diurnal: e.g.? Lunar month: e.g.? 11 11 2025-01-06 Environments Differ in Space: O2 in Marine Envs. Describe the Pattern high in surface waters, decreases with depth Why? (3 main reasons) 1. Wind mixing near surface 2. Photosynthesis in photic zone (lots of light) 3. Microbial degradation as detritus sinks 12 12 2025-01-06 O2 in Fresh Water similar to ocean, but more severe, why? other differences between fresh & sea water? 1.16 Table 22.1 13 13 2025-01-06 O2 in Terrestrial Environments [Fractional] constant but diffusion depends on absolute concentration gradient Dalton’s Law: Ptot=p(N2)+p(O2)+p(CO2)… P(O2) = FO2 X Ptot atmospheric pressure (Ptot) changes with altitude why? Sea Level: PO2 = Everest: PO2 = 14 14 2025-01-06 Physiological Patterns:The Theory 1. Pattern? 2. Pattern? describe describe general term general term 1.6 15 15 2025-01-06 Physiological Regulation: Time Frames 1. Acute: rapid responses to changes in the environment time scale?: seconds – hours e.g. of natural acute env. time scales? often
