1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 40: Animal Form and Function

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animals inhabit almost every part of the biosphere Despite their amazing diversity – All animals face a similar set of problems, including how to nourish themselves

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Form and function are closely correlated Figure 40.1

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Natural selections select for what works best among the available variations in a population

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Evolutionary convergence – Independent adaptation to a similar environmental challenge Figure 40.2a–e (a) Tuna (b) Shark (c) Penguin (d) Dolphin (e) Seal

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Exchange with the Environment Occurs as substances dissolved in the aqueous medium  transported across membranes

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Single-celled protist has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm Figure 40.3a Diffusion (a) Single cell

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Multicellular organisms with body walls that are only two cells thick  facilitate diffusion Figure 40.3b Mouth Gastrovascular cavity Diffusion (b) Two cell layers

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organisms with complex body plans –  highly folded internal surfaces (lg. surface area) specialized for exchanging materials

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings External environment FoodCO 2 O2O2 Mouth Animal body Respiratory system Circulatory system Nutrients Excretory system Digestive system Heart Blood Cells Interstitial fluid Anus Unabsorbed matter (feces) Metabolic waste products (urine) The lining of the small intestine, a diges- tive organ, is elaborated with fingerlike projections that expand the surface area for nutrient absorption (cross-section, SEM). A microscopic view of the lung reveals that it is much more spongelike than balloonlike. This construction provides an expansive wet surface for gas exchange with the environment (SEM). Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM). 0.5 cm 10 µm 50 µm Figure 40.4

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animal form and function are correlated at all levels of organization – cells – tissues – organs – organ systems

12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 4 main categories – Epithelial, connective, muscle, and nervous Tissue Structure and Function

13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Epithelial Tissue Covers the outside of the body and lines organs and cavities within the body – cells are closely joined

14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Epithelial tissue A stratified columnar epithelium A simple columnar epithelium A pseudostratified ciliated columnar epithelium Stratified squamous epithelia Simple squamous epithelia Cuboidal epithelia Basement membrane 40 µm Figure 40.5

15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Connective Tissue Bind and supports other tissues – sparsely packed cells scattered throughout an extracellular matrix

16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Collagenous fiber Elastic fiber Chondrocytes Chondroitin sulfate Loose connective tissue Fibrous connective tissue 100 µm Nuclei 30 µm Bone Blood Central canal Osteon 700 µm55 µm Red blood cells White blood cell Plasma Cartilage Adipose tissue Fat droplets 150 µm CONNECTIVE TISSUE Connective tissue Figure 40.5

17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Muscle Tissue Composed of long cells called muscle fibers, contract in response to nerve signals – 3 types: skeletal, cardiac, and smooth

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Nervous Tissue Senses stimuli and transmits signals throughout the animal

19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Muscle and nervous tissue MUSCLE TISSUE Skeletal muscle 100 µm Multiple nuclei Muscle fiber Sarcomere Cardiac muscle Nucleus Intercalated disk 50 µm Smooth muscle Nucleus Muscle fibers 25 µm NERVOUS TISSUE Neurons Process Cell body Nucleus 50 µm Figure 40.5

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Neurons Figure 48.5 Dendrites Cell body Nucleus Axon hillock Axon Signal direction Synapse Myelin sheath Synaptic terminals Presynaptic cell Postsynaptic cell

21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lumen of stomach Mucosa. The mucosa is an epithelial layer that lines the lumen. Submucosa. The submucosa is a matrix of connective tissue that contains blood vessels and nerves. Muscularis. The muscularis consists mainly of smooth muscle tissue. 0.2 mm Serosa. External to the muscularis is the serosa, a thin layer of connective and epithelial tissue. In some organs tissues are arranged in layers Figure 40.6

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organ systems in mammals Table 40.1

23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organisms require chemical energy for – Growth, repair, physiological processes, regulation, and reproduction

24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Flow of energy through an animal – Limits the animal’s behavior, growth, and reproduction, how much food it needs Bioenergetics

25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy Sources and Allocation Chemical energy from food  food digested  molecules generate ATP  powers cellular work

26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolic needs and biosynthesis Figure 40.7 Organic molecules in food Digestion and absorption Nutrient molecules in body cells Cellular respiration Biosynthesis: growth, storage, and reproduction Cellular work Heat Energy lost in feces Energy lost in urine Heat External environment Animal body Heat Carbon skeletons ATP

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Measuring metabolic rate by amount of oxygen consumed or carbon dioxide produced Figure 40.8a, b This photograph shows a ghost crab in a respirometer. Temperature is held constant in the chamber, with air of known O 2 concentration flow- ing through. The crab’s metabolic rate is calculated from the difference between the amount of O 2 entering and the amount of O 2 leaving the respirometer. This crab is on a treadmill, running at a constant speed as measurements are made. (a) (b) Similarly, the metabolic rate of a man fitted with a breathing apparatus is being monitored while he works out on a stationary bike.

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Birds and mammals are endothermic – bodies warmed by heat generated by metabolism – high metabolic rates

29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Amphibians, reptiles other than birds, and ………..Daphnia are ectothermic – gain their heat from external sources – lower metabolic rates – Q 10

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Size and Metabolic Rate Metabolic rate inversely related to body size among similar animals

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Basal metabolic rate (BMR) – Metabolic rate of an endotherm at rest Standard metabolic rate (SMR) – Metabolic rate of an ectotherm at rest Activity and Metabolic Rate

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animal’s maximum possible metabolic rate is inversely related to the duration of the activity Figure 40.9 Maximum metabolic rate (kcal/min; log scale) 500 100 50 10 5 1 0.5 0.1 AH A H A A A H H H A = 60-kg alligator H = 60-kg human 1 second 1 minute 1 hour Time interval 1 day 1 week Key Existing intracellular ATP ATP from glycolysis ATP from aerobic respiration

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy use Endotherms Ectotherm Annual energy expenditure (kcal/yr) 800,000 Basal metabolic rate Reproduction Temperature regulation costs Growth Activity costs 60-kg female human from temperate climate Total annual energy expenditures (a) 340,000 4-kg male Adélie penguin from Antarctica (brooding) 4,000 0.025-kg female deer mouse from temperate North America 8,000 4-kg female python from Australia Energy expenditure per unit mass (kcal/kgday) 438 Deer mouse 233 Adélie penguin 36.5 Human 5.5 Python Energy expenditures per unit mass (kcal/kgday) (b) Figure 40.10a, b

34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animals regulate their internal environment within relatively narrow limits Homeostasis: balance between external changes and the animal’s internal control mechanisms that oppose the changes

35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Regulator – Uses internal control mechanisms to moderate internal change in the face of external, environmental fluctuation Conformer – Allows its internal condition to vary with certain external changes

36. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Homeostatic control system 3 functional components – receptor, control center, and effector Figure 40.11 Response No heat produced Room temperature decreases Heater turned off Set point Too hot Set point Control center: thermostat Room temperature increases Heater turned on Too cold Response Heat produced Set point

37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Homeostatic control systems function by negative feedback – buildup of the end product shuts the system off

38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Positive feedback – change in some variable that amplify the change

39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Thermoregulation – animals maintain an internal temperature within a tolerable range

40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tolerate greater variation in internal temperature than endotherms Ectotherms Figure 40.12 River otter (endotherm) Largemouth bass (ectotherm) Ambient (environmental) temperature (°C) Body temperature (°C) 40 30 20 10 20 30 40 0

41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energetically more expensive than ectothermy – Buffers animals’ internal temperatures against external fluctuations – High level of aerobic metabolism Endothermy

42. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Heat Exchange Organisms exchange heat by four physical processes Radiation is the emission of electromagnetic waves by all objects warmer than absolute zero. Radiation can transfer heat between objects that are not in direct contact, as when a lizard absorbs heat radiating from the sun. Evaporation is the removal of heat from the surface of a liquid that is losing some of its molecules as gas. Evaporation of water from a lizard’s moist surfaces that are exposed to the environment has a strong cooling effect. Convection is the transfer of heat by the movement of air or liquid past a surface, as when a breeze contributes to heat loss from a lizard’s dry skin, or blood moves heat from the body core to the extremities. Conduction is the direct transfer of thermal motion (heat) between molecules of objects in direct contact with each other, as when a lizard sits on a hot rock. Figure 40.13

43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Insulation Thermoregulatory adaptation in mammals and birds – Reduces the flow of heat between an animal and its environment – e.g. feathers, fur, or blubber

44. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hair Sweat pore Muscle Nerve Sweat gland Oil gland Hair follicle Blood vessels Adipose tissue Hypodermis Dermis Epidermis Mammal integumentary system – Acts as insulating material Figure 40.14

45. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Vasodilation – Blood flow in the skin increases, facilitating heat loss Vasoconstriction – Blood flow in the skin decreases, lowering heat loss Circulatory adaptations

46. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Countercurrent heat exchangers  reduce heat loss In the flippers of a dolphin, each artery is surrounded by several veins in a countercurrent arrangement, allowing efficient heat exchange between arterial and venous blood. Canada goose Artery Vein 35°C Blood flow Vein Artery 30º 20º 10º 33° 27º 18º 9º Pacific bottlenose dolphin 2 1 3 2 3 Arteries carrying warm blood down the legs of a goose or the flippers of a dolphin are in close contact with veins conveying cool blood in the opposite direction, back toward the trunk of the body. This arrangement facilitates heat transfer from arteries to veins (black arrows) along the entire length of the blood vessels. 1 Near the end of the leg or flipper, where arterial blood has been cooled to far below the animal’s core temperature, the artery can still transfer heat to the even colder blood of an adjacent vein. The venous blood continues to absorb heat as it passes warmer and warmer arterial blood traveling in the opposite direction. 2 As the venous blood approaches the center of the body, it is almost as warm as the body core, minimizing the heat lost as a result of supplying blood to body parts immersed in cold water. 3 Figure 40.15 1 3

47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Some bony fishes and sharks also possess countercurrent heat exchangers Figure 40.16a, b 21º 25º 23º 27º 29º 31º Body cavity Skin Artery Vein Capillary network within muscle Dorsal aorta Artery and vein under the skin Heart Blood vessels in gills (a) Bluefin tuna. Unlike most fishes, the bluefin tuna maintains temperatures in its main swimming muscles that are much higher than the surrounding water (colors indicate swimming muscles cut in transverse section). These temperatures were recorded for a tuna in 19°C water. (b) Great white shark. Like the bluefin tuna, the great white shark has a countercurrent heat exchanger in its swimming muscles that reduces the loss of metabolic heat. All bony fishes and sharks lose heat to the surrounding water when their blood passes through the gills. However, endothermic sharks have a small dorsal aorta, and as a result, relatively little cold blood from the gills goes directly to the core of the body. Instead, most of the blood leaving the gills is conveyed via large arteries just under the skin, keeping cool blood away from the body core. As shown in the enlargement, small arteries carrying cool blood inward from the large arteries under the skin are paralleled by small veins carrying warm blood outward from the inner body. This countercurrent flow retains heat in the muscles.

48. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Endothermic insects – countercurrent heat exchangers maintain a high temperature in the thorax Figure 40.17

49. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cooling by Evaporative Heat Loss Lose heat through the evaporation of water in sweat Panting cools bodies

50. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bathing cools animal Figure 40.18

51. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Certain postures enable animals to minimize or maximize their absorption of heat from the sun Figure 40.19

52. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Flying insects use shivering to warm up before taking flight Figure 40.20 PREFLIGHT WARMUP FLIGHT Thorax Abdomen Temperature (°C) Time from onset of warmup (min) 40 35 30 25 0 2 4

53. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The hypothalamus functions as a thermostat Thermoregulation Thermostat in hypothalamus activates cooling mechanisms. Sweat glands secrete sweat that evaporates, cooling the body. Blood vessels in skin dilate: capillaries fill with warm blood; heat radiates from skin surface. Body temperature decreases; thermostat shuts off cooling mechanisms. Increased body temperature (such as when exercising or in hot surroundings) Homeostasis: Internal body temperature of approximately 36–38  C Body temperature increases; thermostat shuts off warming mechanisms. Decreased body temperature (such as when in cold surroundings) Blood vessels in skin constrict, diverting blood from skin to deeper tissues and reducing heat loss from skin surface. Skeletal muscles rapidly contract, causing shivering, which generates heat. Thermostat in hypothalamus activates warming mechanisms. Figure 40.21

54. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Acclimatization Animals can adjust to a new range of environmental temperatures over a period of days or weeks

55. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Torpor Adaptation that enables animals to save energy while avoiding difficult and dangerous conditions – physiological state of low activity and metabolism

56. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hibernation (long-term torpor) Additional metabolism that would be necessary to stay active in winter Actual metabolism Body temperature Arousals Outside temperature Burrow temperature JuneAugustOctoberDecemberFebruaryApril Temperature (°C) Metabolic rate (kcal per day) 200 100 0 35 30 25 20 15 10 5 0 -5 -10 -15 Figure 40.22

57. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Estivation, or summer torpor – survive long periods of high temperatures and scarce water supplies