Animal Adaptations to Environmental Challenges

1. Chapter 7 Animal adaptations to the Environments

2. Challenges of terrestrial animals • Temperature • Moisture

4. Surface area-volume ratio

6. Adaptation to temperature

7. Adaptations to temperatures

8. Body Temperature Regulation • Ectotherms • Rely mainly on external energy sources. • Endotherms • Rely heavily on metabolic energy. • Poikilotherms • Body temperature varies directly with environmental temperature. • Homeotherms • maintain a relatively constant internal environment

9. Temperature Regulation by Ectothermic Animals

10. Behavioral thermoregulation

12. Acclimatization: long-term temperature regulation

13. Temperature Regulation by Endothermic Animals • Thermal neutral zone is the range of environmental temperatures over which the metabolic rate of a homeothermic animal does not change. • Breadth varies among endothermic species.

18. Countercurrent heat exchange

22. 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 Migration

26. Adaptation to water

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

28. Water Regulation on Land • Wia= Wd + Wf + Wa - We - Ws • Wia= Animal’s internal water • Wd = Drinking • Wf = Food • Wa = Absorbed by air • We = Evaporation • Ws = Secretion / Excretion

29. Water Regulation on Land

30. Water Acquisition • Most terrestrial animals satisfy their water needs via eating and drinking. • Can also be gained via metabolism through oxidation of glucose: • C6H12O6 + 6O2 6CO2 + 6H2O • Metabolic water refers to the water released during cellular respiration.

31. Water regulation of terrestrial animals

35. (III)Water Movement in Aquatic Environments • If two environments differ in water or salt concentrations, substances will tend to move down their concentration gradients. • Diffusion • Osmosis: Diffusion through a semipermeable membrane.

36. (III) Water Movement in Aquatic Environment • Isomotic: Body fluids and external fluid are at the same concentration. • Hypoosmotic: Body fluids are at a higher concentration than the external environment. • Hyperosmotic: Body fluids are at a lower concentration than the external environment.

37. loss Gain Gain loss

38. Water regulation of hyperosmotic animals (IV) Water and Salt Balance

39. Hypoosmotic animals

40. Mitochondria-rich cell

41. 上課完畢，謝謝!