1. Abiotic Factors Resources Factors

3. Tolerance Range Homeostasis

4. Optimal Growth Temperatures Microbial Activity

5. Temperature

6. Aquatic Temperatures Riparian vegetation influences stream temperature by providing shade.

7. Homeostasis Definition Mechanisms –Physiological –Behavioral

8. Thermoneutral Zone

9. LETHAL TEMPERATURE RELATIONS FOR TWO SPECIES OF FISH. ENCLOSED AREA OF EACH TRAPEZIUM IS THE ZONE OF TOLERANCE

10. Thermoneutral Zones

11. Microclimates Macroclimate: Microclimate: Altitude Higher altitude - lower temperature. –Aspect Offers contrasting environments. –Vegetation Ecologically important microclimates.

13. Microclimates Ground Color Boulders / Burrows

14. Microclimate The distribution of species and temperature contour maps do not always coincide This is because the temperatures organisms experience are greatly effected by numerous things. –Behavior of animals –North-facing & south-facing slopes

16. Plant Resources Solar radiation (energy source) Water CO 2 Minerals (nutrients)

17. Saguaro cactus (Cereus giganteus) Distribution determined by temp. Limited by temperature remaining below freezing for 36 hr. Dots are sites where temp. remains below freezing for 36 hr. or more. “X’s” are sites where these conditions have not been recorded. The dotted line is the boundary of the Sonoran desert.

18. Optimal Photosynthetic Temperatures

19. Stomata –Bring CO 2 in –Allow H 2 O to escape

20. Heat Exchange Pathways

21. Temperature Regulation by Plants Desert Plants: Must reduce heat storage. –H s = H cd + H cv + H r

22. Temperature Regulation by Plants

23. Arctic and Alpine Plants – Two main options to stay warm: Tropic Alpine Plants –Rosette plants generally retain dead leaves, which insulate and protect the stem from freezing.

25. Yarrow (Achillea) along an altitudinal gradient WestEast Sierra-Nevada Range

26. Natural Selection High temperature High humidity Low temperature Low humidity Many Generations Cold genotype Moderate genotype Warm genotype

27. Animal Resources & Factors Temperature Oxygen, water Nutrition (energy source) Defense Intraspecific competition

28. Temperature and Animal Performance Biomolecular Level –Most enzymes have rigid, predictable shape at low temperatures

29. Heat Transfer H tot = H c ± H r ± H s - H e H tot = total metabolic heat H c = Conductive & convective H r = Radiative H s = Storage H e = evaporation Heat Exchange Pathways

30. Body Temperature Regulation Poikilotherms Homeotherms

31. Body Temperature Regulation Poikilotherms Homeotherms

32. Body Temperature Regulation Ectotherms Endotherms

33. Temperature Regulation by Ectothermic Animals Liolaemus Lizards –Thrive in cold environments Burrows Dark pigmentation Sun Basking

34. Temperature Regulation by Ectothermic Animals Grasshoppers –Some species adjust for radiative heating by varying intensity of pigmentation during development

35. Temp Regulation - costs

36. Temperature Regulation by Endothermic Animals Regional Heterothermy

37. Countercurrent heat exchange:

38. Countercurrent Heat Exchange

39. Temperature Regulation

40. rete mirabile

41. 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

42. Surviving Extreme Temperatures Inactivity Reduce Metabolic Rate

43. Adaptations to Environmental Extremes Dormancy –Diapause –Torpor –Hibernation –Estivation Bergman’s Rule Allen’s Rule

44. Dormancy Diapause

45. Temp. Regulation

46. Bergmann’s Rule –Retains heat better

47. Bergmann’s Rule

48. Allen’s Rule

49. Water Movement in Aquatic Environments Water moves down concentration gradient –freshwater vs. saltwater Aquatic organisms can be viewed as an aqueous solution bounded by a semi- permeable membrane floating in an another aqueous solution

50. Water Movement in Aquatic Environments If 2 environments differ in water or salt concentrations, substances move down their concentration gradients –Diffusion Osmosis:

51. Water Movement in Aquatic Environment Isomotic: –[Salt] –body fluids = external fluid Hypoosmotic: –[Salt] < –body fluids > external fluid –Water moves out Hyperosmotic: –[Salt] > –body fluids < external fluids –Water moves in

52. Water Regulation on Land Terrestrial organisms face (2) major challenges: –Evaporative loss to environment. –Reduced access to replacement water.

53. Water Regulation on Land - Plants

54. W ip = W r + W a - W t - W s W ip = Plant’s internal water W r =Roots W a = Air W t = Transpiration W s = Secretions

55. Water Regulation on Land - Animals

56. W ia = W d + W f + W a - W e - W s W ia = Animal’s internal water W d = Drinking W f = Food W a = Absorbed by air W e = Evaporation W s = Secretion / Excretion

57. Water Acquisition by Animals Most terrestrial animals satisfy their water needs via eating and drinking. –Can also be gained via metabolism through oxidation of glucose: C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O –Metabolic water refers to the water released during cellular respiration.

58. Water Conservation by Plants and Animals Many terrestrial organisms equipped with waterproof outer covering. Concentrated urine / feces. Condensing water vapor in breath. Behavioral modifications to avoid stress times. Drop leaves in response to drought. Thick leaves Few stomata Periodic dormancy

59. Figure 3.17 Kangaroo rat, in SW USA, forages for food at night; benefit of cooler air temps. Water conserved via condensation in large nasal passages and lungs.

60. Loop of Henle in mammal kidney

61. Dissimilar Organisms with Similar Approaches to Desert Life Camels –Can withstand water loss up to 20%. Face into sun to reduce exposure. Thick hair: Increased body temperature lowers heat gradient. Saguaro Cactus –Trunk / arms act as water storage organs. –Dense network of shallow roots. –Reduces evaporative loss.

63. Temperatures above thermoneutrality –Become hyperthermic by raising T B to near T A, thereby reducing water loss and continuing dry heat transfer e.g., many desert mammals

64. Readings Ecological Issues (EI): Urban Microclimates, p. 34 EI – Groundwater Resources, p.39 Quantifying Ecology 4.1, pp.59-60 Field Studies – Kaoru Kitajima, pp. 112-113 Quantifying Ecology 7.1, pp. 140-141