1. Temperature Relations (Ch. 5)

2. Endothermic Animals

3. H S = H m + H cd + H cv + H r - H e Use behavior + metabolism (H m ) too

4. Endothermic Animals Thermal neutral zone: range temperature where metabolic rate stable –Varies by species Humans?

5. Endothermic Animals Humans tropical: all over planet!

6. Aquatic Endothermic Animals Cold water problem –Convective heat loss: 20x faster than air (still water) to 100x faster (moving water) Solutions? (3) “Stop the lecture, you’re killing me!”

7. Aquatic Endothermic Animals Solutions: 1) breathe air (avoid gill surface exposure) 2) insulate! Blubber (whales), waterproof feathers (penguins), air-trapping fur (sea otters) “Stop the lecture, you’re killing me!” Otter fur: up to 1 million /sq. in.

8. Aquatic Endothermic Animals Solutions: 3) limit heat loss from appendages by countercurrent heat exchangers

9. Exceptional fishes Some fishes regulate temp. swimming muscles Ex, bluefin tuna (fast!)

10. Exceptional fishes Countercurrent heat exchange keeps muscle temp. constant –Artery blood cooler in this case…

11. Surviving Extreme Temperatures Reducing Metabolic Rate –Hummingbirds: enter torpor (reduce metabolic rate & lower body temp.) Months?

12. Surviving Extreme Temperatures Reducing Metabolic Rate (for months) –Hibernation - Winter (temperate climates) –Ex, black bear Avoid summer?

13. Surviving Extreme Temperatures Reducing Metabolic Rate (for months) –Estivation - Summer (deserts) –Ex, lungfishes –Bury in mud to survive dry season

14. Water Relations (Ch. 6)

15. Why Water Matters Life aquatic (you: 60% water!) Solute concentration affects enzymes Water useful: temp. regulation –H S = H m + H cd + H cv + H r - H e

16. Water Content Air Terrestrial: Most water loss evaporation (concentration gradient) –How express air water content?

17. Water Content Air Relative Humidity: Water Vapor Density Saturation Water Vapor Density (x 100%) –Water vapor density = gm water vapor per unit volume (meter cubed) –Saturation water vapor density = water vapor air potentially holds Changes with temperature…..(how?)

18. Water Content Air Note kPa: pressure unit (kiloPascals) Pascal: metric unit pressure (1 Newton per sq. meter) Vapor pressure….

19. Water Content Air Water Vapor Pressure (WVP): Partial pressure water vapor. Saturation Water Vapor Pressure (SWVP): Pressure water vapor at saturation Vapor Pressure Deficit (VPD): SWVP – WVP: drying power air

20. Water Movement: Soil to Plant Water: flows down water potential gradient Water potential?

21. Water Movement: Soil to Plant Water: flows down water potential gradient. Water potential (Psi): capacity water to perform work (water’s free energy content) “Tendency water to move from one place to another” –Pure Water Psi = 0 MegaPascals (MPa) Psi Mega = one million (10 6 )

22. Units: megaPascals (MPa) Psi values negative! Why? Mega = one million (10 6 )

23. Psi values negative! Why? Water potential lowered by: –Dissolved substances (solute potential) –Attraction water to charged surfaces (matric potential) –Pull of evaporation (tension) on water in plants (negative pressure potential) Water potential raised by: –Pressure (positive pressure potential) Water Movement: Soil to Plant

24. Psi plant = Psi solute + Psi matric + Psi pressure Psi soil = Psi solute + Psi matric Solute potential: salts. Psi solute important saline soils Matric potential (#1 all soils): attraction water to clays (tiny mineral materials) in soil Water Movement: Soil to Plant

25. Concept! If Psi plant < Psi soil, water flows to plant Water Movement: Soil to Plant

26. Water Regulation on Land

27. Terrestrial organism challenges: –Evaporative loss (air dry) –Access replacement water Water Regulation on Land Recall Energy Balance Equation: H S = H m + H cd + H cv + H r - H e Now: one for water…

28. Water Regulation: Plants W ip = W r + W a - W t - W s W ip = Plant internal water W r = Roots (+) W a = Air (+: humid spots) W t = Transpiration (evaporation from tissues) W s = Secretions (nectar) Next: roots

29. Water Acquisition: Plants How get water? W ip = W r + W a - W t - W s –Dry sites: more roots! Plant from W. Canada grasslands

30. W ia = W d + W f + W a - W e - W s W ia = Animal internal water W d = Drinking (+) W f = Food (+) W a = Absorbed from air (+) W e = Evaporation (-) W s = Secretions (-) Water Regulation on Land: Animals Focus: how get water

31. Water Acquisition by Animals W ia = W d + W f + W a - W e - W s Most land animals: get water by eating & drinking (“preformed water”) Some watering hole photos...

32. Water Acquisition by Animals Water gained via metabolism (metabolic water) C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O Water made by aerobic respiration. Who am I?

33. Water Acquisition by Animals W ia = W f - W e – W s

34. Water Acquisition by Animals Special adaptations: behavior Namib desert (S. Africa) Fog from Atlantic Lizard flashback

35. Water Acquisition by Animals Onymacris beetle