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Chapter 40: Basic Principles of Animal Form and Function Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.1 A sphinx moth feeding on orchid nectar Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.2 Evolutionary convergence in fast swimmers (a) Tuna (b) Shark (c) Penguin (d) Dolphin (e) Seal Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.3 Contact with the environment Mouth Diffusion Gastrovascular cavity Diffusion Diffusion (a) Single cell Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings (b) Two cell layers Figure 40.4 Internal exchange surfaces of complex animals External environment Food CO2 O2 Mouth Respiratory system 0.5 cm Cells Heart Nutrients Circulatory system 50 µm Animal body 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). 10 µm Interstitial fluid Digestive system Excretory system The lining of the small intestine, a digestive organ, is elaborated with fingerlike projections that expand the surface area for nutrient absorption (cross-section, SEM). Anus Unabsorbed matter (feces) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolic waste products (urine) Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM). Table 40.1 Organ Systems: Their Main Components and Functions in Mammals Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.6 Tissue layers of the stomach, a digestive organ 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. Serosa. External to the muscularis is the serosa, a thin layer of connective and epithelial tissue. 0.2 mm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.8 Measuring metabolic rate (a) This photograph shows a ghost crab in a respirometer. Temperature is held constant in the chamber, with air of known O2 concentration flowing through. The crab’s metabolic rate is calculated (b) Similarly, the metabolic rate of a man fitted with a breathing apparatus is from the difference between the amount of O2 being monitored while he works out entering and the amount of O2 leaving the on a stationary bike. respirometer. This crab is on a treadmill, running at a constant speed as measurements are made. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.10 Energy budgets for four animals Annual energy expenditure (kcal/yr) Endotherms 800,000 Reproduction Basal metabolic rate Ectotherm Temperature regulation costs Growth Activity costs 340,000 8,000 4,000 60-kg female human from temperate climate 4-kg male Adélie penguin from Antarctica (brooding) (a) Total annual energy expenditures 0.025-kg female deer mouse from temperate North America 4-kg female python from Australia Energy expenditure per unit mass (kcal/kg•day) 438 Human 233 Python Deer mouse Adélie penguin (b) Energy expenditures per unit mass (kcal/kg•day) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 36.5 5.5 Figure 40.11 A nonliving example of negative feedback: control of room temperature Response No heat produced Heater turned off Room temperature decreases Too hot Set point Too cold Set point Set point Control center: thermostat Room temperature increases Heater turned on Response Heat produced Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.12 The relationship between body temperature and environmental temperature in an aquatic endotherm and ectotherm 40 Body temperature (°C) River otter (endotherm) 30 20 Largemouth bass (ectotherm) 10 0 10 20 30 Ambient (environmental) temperature (°C) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 40 Figure 40.13 Heat exchange between an organism and its environment 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. 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. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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. 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 40.14 Mammalian integumentary system Hair Epidermis Sweat pore Muscle Dermis Nerve Sweat gland Hypodermis Adipose tissue Blood vessels Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Oil gland Hair follicle Figure 40.18 A terrestrial mammal bathing, an adaptation that enhances evaporative cooling Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.21 The thermostat function of the hypothalamus in human thermoregulation Sweat glands secrete sweat that evaporates, cooling the body. Thermostat in hypothalamus activates cooling mechanisms. Increased body temperature (such as when exercising or in hot surroundings) Blood vessels in skin dilate: capillaries fill with warm blood; heat radiates from skin surface. Body temperature decreases; thermostat shuts off cooling mechanisms. Homeostasis: Internal body temperature of approximately 36–38C 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. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Thermostat in hypothalamus activates warming mechanisms.