1. BSU IN AFS meeting Tue Aug 23TONIGHT! 5:00 pm CL 167 Electrofishing demonstration

2. Genetics Club meeting Wed Aug 28 7:00 pm CL 268 (genetics lab) Biology jeopardy and snacks

3. Chapter 5 Temperature relations Probably the most limiting factor in organism’s distributions Active animal life limited between ~ 0 ˚ C and 50 ˚ C

4. Dilemma of life Organisms need energy + nutrients

5. Dilemma of life Organisms need energy + nutrients Enzymes function under narrow ranges of T

6. Dilemma of life Organisms need energy + nutrients Enzymes function under narrow ranges of T Internal environment differs from external = gradient = dilemma

7. T varies in time + space Temporal (daily, seasonal, multi-year, long-term changes)

8. T varies in time + space Temporal (daily, seasonal, multi-year, long-term changes) Spatial (latitude, elevation, aspect, microclimate)

9. T varies in time + space Temporal (daily, seasonal, multi-year, long-term changes) Spatial (latitude, elevation, aspect, microclimate) Less variable in aquatic habitats

10. Dealing With It: ADAPTATION Optimum conditions for physiological activity match the prevailing environmental conditions Downside: Species can only survive in specific environments

11. >>>>>>>>> Optimum Range of Limitation Protein Denaturation Temperature O2 Uptake Metabolic Rate CO2 Uptake Heart Rate Temperature Response Curve

12. T response curve Species from warm vs cold environments differ in T responses

13. Adaptations to deal with extreme T Mechanisms to regulate body T –Control radiative heat gain/loss –Control convective heat gain/loss –Evaporative heat dissipation –Metabolic heat gain –Control T of critical tissues only

15. Adaptations to deal with extreme T Mechanisms to avoid extreme T –Seasonal migration –Daily/hourly movements –Physiological dormancy

18. Definitions: Acclimation = short-term change in morphology or physiology Adaptation = evolutionary change in morphology or physiology

20. Badlands, SD

22. Glacier National Park, MT

24. Acclimation example: Desert shrubs –A. glabriuscula saltbrush from cool coastal CA –T. oblongifolia from Death Valley

25. Acclimation example: Desert shrubsDesert shrubs

26. Goldfish acclimation

27. Solid line = range of thermal tolerance Dash = acclimation T E.g., fish kept at 30 C has upper lethal limit of 38 C and lower lethal limit of 9 C

29. Trade-offs for T regulation Poikilotherms:Poikilotherms: –Inactive when T is not optimum Result:Result: –Low energy needs for homeostasis

31. Poikilotherms can regulate T with behavior (ectothermic) In deserts, shade under shrub can be 25˚CIn deserts, shade under shrub can be 25˚C Ground exposed to sun can be > 60˚ CGround exposed to sun can be > 60˚ C Desert iguana maintains body T 39 - 43˚C by changing microhabitatsDesert iguana maintains body T 39 - 43˚C by changing microhabitats

32. Trade-offs for T regulation Homeotherms: –Metabolic rate to heat –Evaporative water to cool Result: –Loss of resources for repro, growth, etc.

33. Cost-Benefit of Metabolic Thermo-Regulation Benefit: Species can be active in cold environments (increases opportunity to acquire resources) Cost: Energy expended to generate heat is not available for growth or reproduction Most advantageous in environments where energy (food) is abundant

34. Eastern skunk cabbage

35. Air temperature and cabbage metabolic rate

36. Water temp and body temp of bluefin tuna

37. Minimizing Cost of Metabolic Thermo-Regulation Increase RESISTANCE to heat loss / gain b/t body and environment. –Fur, Feathers, Fat Layer (Insulation) –Low body surface-to-volume ratio Large body size Shorter / Fewer appendages and elongation

40. Answer a question: Are most organisms tolerant of a wide range of temperatures or a narrow range of temperatures?