1. 1 Temperature Relations Chapter 4

2. 2 Microclimates Macroclimate: Large scale weather variation. Microclimate: Small scale weather variation, usually measured over shorter time period.  Altitude  Higher altitude - lower temperature.  Aspect  North-face shaded in Northern Hemisphere.  Offers contrasting environments.  Vegetation  Ecologically important microclimates.

3. 3 North

4. 4 Microclimates Ground Color  Darker colors absorb more visible light. Boulders / Burrows  Create shaded, cooler environments.

5. 5 Temperature Response of Metabolic Processes Enzymes:  Optimum temperature.  Multiples isozymes with different optima. Complex Processes:  Photosynthetic optimal temperature.  Acclimation within species (physiological) Whole organism:  Cardinal temperatures (min, optimum, max)  Bacteria to man.

6. 6 04_08.jpg

7. 7 Optimal Photosynthetic Temperatures

8. 8

9. 9 Body Temperature Regulation Poikilotherms  Body temperature varies directly with environmental temperature. Ectotherms  Rely mainly on external energy sources.  Behavior and anatomical features used. Endotherms  Rely heavily on metabolic energy.  Homeotherms maintain a relatively constant internal environment (birds and mammals)

10. 10 Balancing Heat Gain Against Heat Loss H S = H m + H cd + H cv + H r - H e  H S = Total heat stored in an organism  H m = Gained via metabolism  H cd = Gained / lost via conduction  H cv = Gained / lost via convection  H r = Gained / lost via electromag. radiation  H e = Lost via evaporation

11. 11 Heat Exchange Pathways

12. 12 Temperature Regulation by Plants (ectothermy)

13. 13

14. 14

15. 15

16. 16 Temperature Regulation by Animals (ectothermy) Move to …. (e.g. Angilletta’s lizards) Pigmentation (e.g. Curruther’s grasshoppers)

17. 17 Temperature Regulation by Endothermic Animals Cooling:  Anatomical features.  Evaporative cooling. Thermal neutral zone is the range of environmental temperatures over which the metabolic rate of a homeothermic animal does not change.  Breadth of TNZ varies among endotherms.  Tropics narrow TNZ  Polar broad TNZ

18. 18 Thermal Neutral Zones

19. 19 Endotherms Surviving Extreme Temperatures Inactivity  Seek shelter during extreme periods. Reducing Metabolic Rate  Hummingbirds enter a state of torpor when food is scarce and night temps are extreme.  Hibernation - Winter  Estivation - Summer

20. 20 Countercurrent Heat Exchange

21. 21 http://www.bio.davidson.edu/Courses/anphys/2000/CrawfordR/ccbloodflow.htm

22. 22 Temperature Regulation by Endothermic Animals Warming Insect Flight Muscles  Bumblebees maintain temperature of thorax between 30 o and 37 o C regardless of air temperature and flight activity.  Sphinx moths (Manduca sexta) increase thoracic temperature due to flight activity.  Thermoregulates by transferring heat from the thorax to the abdomen

23. 23 Temperature Regulation by Thermogenic Plants Almost all plants are poikilothermic ectotherms.  Plants in family Araceae use metabolic energy to heat flowers.  Skunk Cabbage (Symplocarpus foetidus) stores large quantities of starch in large root, and then translocate it to the inflorescence where it is metabolized thus generating heat.

24. 24 Eastern Skunk Cabbage

25. 25 Sources for images http://astrosun.tn.cornell.edu/~shami/smoky/lizard.jpg http://www.sf.airnet.ne.jp/~yasuda/main/greenland/mo02.jpg http://www.gotostcroix.com/hiking/images/cactus.jpg http://wenlin.network.com.tw/goat/Old_Data/~english/alpine_plant/450/plant_29. JPG http://wenlin.network.com.tw/goat/Old_Data/~english/alpine_plant/450/plant_29. JPG http://www.americansouthwest.net/slot_canyons/photographs700/creosotebush.jpg http://www.americansouthwest.net/slot_canyons/photographs700/creosotebush.jpg http://en.wikipedia.org/wiki/Image:Bumblebee_closeup_cropped.jpg