Basic Principles of Animal Form and Function Chapter 40: Basic Principles of Animal Form and Function

Figure 40.1 A sphinx moth feeding on orchid nectar

Figure 40.2 Evolutionary convergence in fast swimmers (a) Tuna (b) Shark (c) Penguin (d) Dolphin (e) Seal

Figure 40.3 Contact with the environment Diffusion (a) Single cell Mouth Gastrovascular cavity (b) Two cell layers

Figure 40.4 Internal exchange surfaces of complex animals External environment Food CO2 O2 Mouth Animal body Respiratory system Circulatory Nutrients Excretory Digestive 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

Table 40.1 Organ Systems: Their Main Components and Functions in Mammals

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. 0.2 mm Serosa. External to the muscularis is the serosa, a thin layer of connective and epithelial tissue.

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 flow- ing through. The crab’s metabolic rate is calculated from the difference between the amount of O2 entering and the amount of O2 leaving the respirometer. This crab is on a treadmill, running at a constant speed as measurements are made. (b) Similarly, the metabolic rate of a man fitted with a breathing apparatus is being monitored while he works out on a stationary bike.

Figure 40.10 Energy budgets for four animals 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/kg•day) 438 Deer mouse 233 Adélie penguin 36.5 Human 5.5 Python Energy expenditures per unit mass (kcal/kg•day) (b)

Figure 40.11 A nonliving example of negative feedback: control of room temperature Response No heat produced Room temperature decreases Heater turned off Set point Too hot Set point Control center: thermostat increases on cold Heat

Figure 40.12 The relationship between body temperature and environmental temperature in an aquatic endotherm and ectotherm River otter (endotherm) Largemouth bass (ectotherm) Ambient (environmental) temperature (°C) Body temperature (°C) 40 30 20 10

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. 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 40.14 Mammalian integumentary system Hair Sweat pore Muscle Nerve gland Oil gland Hair follicle Blood vessels Adipose tissue Hypodermis Dermis Epidermis

Figure 40.18 A terrestrial mammal bathing, an adaptation that enhances evaporative cooling

Internal body temperature Figure 40.21 The thermostat function of the hypothalamus in human 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 Increased body temperature (such as when exercising or in hot surroundings) Homeostasis: Internal body temperature of approximately 36–38C increases; shuts off warming Decreased body temperature (such as when in cold 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. activates warming