1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 40 Basic Principles of Animal Form and Function

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overview: Diverse Forms, Common Challenges Animals inhabit almost every part of the biosphere Despite their diversity, all animals face similar problems, including how to get nourishment Form and function are closely correlated Natural selection can fit structure/anatomy to function/physiology by selecting (over generations) what works best among the available variations in a population Figure 40.1 A sphinx moth feeding on orchid nectar.

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 40.1 Physical laws & env constrain animal size/shape Physical laws & the need to exchange materials w/environment place limits on the range of animal forms Physical Laws and Animal Form The ability to perform certain actions depends on an animal’s shape and size

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Evolutionary convergence – Reflects different species’ independent adaptation to a similar environmental challenge Figure 40.2a–e Evolutionary convergence in fast swimmers.

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Exchange with the Environment Animal size/shape have a direct effect on how energy/materials are exchanged w/surroundings – Exchange occurs as substances dissolve in the aqueous medium – they diffuse and are transported across the cells’ plasma membranes A single-celled water protist has sufficient surface area to serve its volume of cytoplasm Figure 40.3 Contact w/the environment. (a) In a unicellular protist, like the amoeba, the entire surface area contacts the environment.

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Multicelled organisms w/sac body plan have body walls that are 2 cells thick, helps material diffusion Figure 40.3 Contact w/the environment. (b) A hydra’s body consists of 2 layers of cells. B/c the aq environment can circulate in and out of the hydra’s mouth, virtually every one of its cells directly contacts the environment and exchanges materials w/it. Organisms with more complex body plans have highly folded internal surfaces specialized for exchanging materials

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.4 Internal exchange surfaces of complex animals. Figure illustrates the logistics of chemical exchange w/the env by a mammal. Most animals have surfaces that are specialized for exchanging certain chemicals w/the surroundings. These surfaces are usually internal, but are connected to the env via openings on the body surface (mouth for ex). The exchange surfaces are finely branched or folded, giving large surface area. The digestive, respiratory, and excretory systems have all such exchange surfaces. Chemicals transported across these surfaces are carried throughout the body by the circulatory system.

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animals are composed of cells Groups of cells with a common structure and function make up tissues Different tissues make up organs Organs work together to make organ systems 40.2 Animal form/function are correlated w/levels of org

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Different types of tissues have diff structures that suit their functions Tissues are classified into four main categories – Epithelial, connective, muscle, nervous Tissue Structure and Function

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Epithelial Tissue Epithelial tissue – Covers the body and lines organs & cavities within the body – Contains cells that are closely joined

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.5 Structure and Function in Animal Tissues

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

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14. Muscle tissue – Composed of long cells called muscle fibers capable of contracting in response to nerve signals – Divided in the vertebrate body into three types: 1 – skeletal 2 – cardiac 3 – smooth Nervous tissue – Senses stimuli & transmits signals throughout animal

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16. Organs and Organ Systems In all but the simplest animals different tissues are organized into organs

17. 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, t he tissues are arranged in layers Organ systems carry out major body ftns in most animals Figure 40.6 Tissue layers of the stomach. The wall of the stomach and other tubular organs of the digestive system has 4 main tissue layers.

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bioenergetics = flow of energy thru an animal – Ultimately limits the animal’s behavior, growth, & reproduction – Determines how much food it needs Studying an animal’s bioenergetics tells us about the animal’s adaptations 40.3 Animals Use Food’s Chem E-Sustain Form/Ftn

19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy Sources and Allocation Once digested, the energy-containing molecules are used to make ATP, which powers cellular work After the E needs of staying alive are met, remaining food molecules can be used in biosynthesis Figure 40.7 Bioenergetics of an animal: an overview

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Metabolic rate is the amt of E an animal uses/unit time – Can be measured in a variety of ways One way is to determine the amount of O 2 consumed or CO 2 produced by an organism Quantifying Energy Use Figure 40.8 Measuring metabolic rate

21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings An animal’s metabolic rate is closely related to its bioenergetic strategy Birds and mammals are mainly endothermic – their bodies are warmed mostly by heat generated by metabolism – They typically have higher metabolic rates Amphibians and reptiles other than birds are ectothermic – they gain heat mostly from external sources – They typically have lower metabolic rates Bioenergetic Strategies

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animal metabolic rate is affected by many factors – Size – Activity Influences on Metabolic Rate Size Metabolic rate/gram is inversely related to body size among similar animals

23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Has a large effect on metabolic rate for both endo and ectotherms – Basal metabolic rate (BMR) - rate of an endotherm at rest – Standard metabolic rate (SMR) - rate of an ectotherm at rest Generally, an animal’s max possible metbolic rate is inversely related to the duration of the activity Activity

24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.9 Maximum metabolic rates over different time spans. The bars compare an ectotherm (alligator) and an endotherm (human) for their max potential metabolic rates & ATP sources over different durations of time. The human’s basal metabolic rate (about 1.2 kcal/min) is much greater than the alligator’s standard metabolic rate (about 0.04 kcal/min). The human’s higher BMR partly contributes to his ability to sustain a higher max metabolic rate over a longer period. 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

25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Different animal species use food’s E and material in different ways, depending on their environment An animal’s energy use is partitioned to BMR (or SMR), activity, homeostasis, growth, reproduction Energy Budgets Figure 40.10 (a) Total annual energy expenditures. The pie charts indicate energy expenditures for various functions. (b) Energy expenditures per unit mass (kcal/kg*day). Comparing the daily energy expenditures per kg of body weight for the 4 animals reinforces impt concepts of bioenergetics. First, a small animal, like a mouse, has a greater energy demand per kg than does a large animal of the same taxonomic class, such as a human (both mammals). Second, note again that an ectotherm, like a python, requires much less energy per kg than does an endotherm of equivalent size, such as a penguin.

26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 40.4 Animals Regulate Internal Env w/in Narrow Limits A vertebrate’s internal environment is called the interstitial fluid. It’s very different from the external environment Homeostasis = balance between external changes and the animal’s internal control mechanisms that oppose the changes

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2 extremes on how animals cope w/env fluctuations An animal is said to be a regulator – If it used internal control mechanisms to moderate internal change in the face of external, env fluctuation An animal is said to be a conformer – If it allows its internal condition to vary w/certain external changes Regulating and Conforming

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Mechanisms of Homeostasis A homeostatic control system has 3 components – A receptor – A control center – And an effector

29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Most homeostatic control systems function by negative feedback – The buildup of the system’s end product shuts the system off Figure 40.11 A nonliving ex of negative feedback: control of room temperature. Regulating room temp depends on a control center that detects temp change and activates mechanisms that reverse that change.

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A second type of homeostatic control system is positive feedback – Involves a change in some variable that triggers mechanisms that amplify the change

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 40.5 Thermoregulation Contributes to Homeostasis & Involves Anatomy, Physiology, Behavior Thermoregulation = the process by which animals maintain an internal temp w/in a tolerable range Ectotherms – Include most invertebrates, fishes, amphibians, and non-bird reptiles Endotherms – Include birds and mammals

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings In general, ectotherms tolerate greater variation in internal temp than endotherms Figure 40.12 The relationship between body temperature and environmental temp in an aquatic endotherm and ectotherm. Using its high metabolic rate to generate heat, the river otter maintains a stable body temp across a wide range of env temps. The largemouth bass, meanwhile, generates relatively little metabolic heat and conforms to the water temp River otter (endotherm) Largemouth bass (ectotherm) Ambient (environmental) temperature (°C) Body temperature (°C) 40 30 20 10 20 30 40 0

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Endothermy is more energetically expensive than ectothermy – But buffers animals’ internal temperatures against external fluctuations – And enables the animals to maintain a high level of aerobic metabolism

34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Modes of Heat Exchange 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 Heat exchange between an organism and its environment.

35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Balancing Heat Loss and Gain Thermoregulation involves physiological & behavioral adjustments that balance heat gain/loss Insulation, a major thermoregulatory adaptation in mammals and birds, reduces the flow of heat between an animal & its environment – May include feathers, fur, or blubber

36. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings In mammals, the integumentary system acts as insulating material Figure 40.14 Mammalian integumentary system. The skin and its derivatives serve impt ftns in mammals, incl protection and thermoregulation.

37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Many endotherms/some ectotherms can alter the amt of blood flowing between the body core and the skin In vasodilation – Blood flow in the skin increases, facilitating heat loss In vasoconstriction – Blood flow in the skin decreases, lowering heat loss Circulatory Adaptations

38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Many marine mammals & birds have arrangements of blood vessels called countercurrent heat exchangers that are impt for reducing heat loss Figure 40.15 Countercurrent heat exchangers. A countercurrent heat exchanger traps heat in the body core, thus reducing heat loss from the extremities, which are often immersed in cold water or in contact w/snow/ice. In essence, heat in the arterial blood emerging from the body core is transferred directly to the returning venous blood instead of being lost to the environment.

39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Some specialized bony fishes & sharks also possess countercurrent heat exchangers Figure 40.16a, b Thermoregulation in large, active bony fishes and sharks. 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) Unlike most fishes, the bluefin tuna maintains temps in its main swimming muscles that are much higher than the surrounding water (colors indicate swimming muscles cut in transverse section). These temps were recorded for a tuna in 19°C water. (b) 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 & sharks lose heat to the surrounding water when their blood passes thru the gills. However, endothermic sharks have a sm 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, sm arteries carrying cool blood inward from the lg 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.

40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Many endothermic insects have countercurrent heat exchangers that help maintain a high temperature in the thorax Figure 40.17 Internal temp in the winter moth. This infrared map shows the moth’s heat distribution immediately after a flight. Red in the thorax region indicates the highest temp. Moving outward, the various color zones correspond to regions of progressively lower body temp.

41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cooling by Evaporative Heat Loss Many animal types – Lose heat through the evaporation of water in sweat – Use panting to cool their bodies Bathing moistens the skin & helps cool animals Figure 40.18 A terrestrial mammal bathing, an adaptation that enhances evaporative cooling.

42. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Endotherms & ectotherms use a variety of behavioral responses to control body temp Some terrestrial invertebrates have certain postures that enable them to minimize or maximize their heat absorption from the sun Behavioral Responses Figure 40.19 Thermoregulatory behavior in a dragonfly. This dragonfly’s ‘obelisk’ posture is an adaptation that minimizes the amount of body surface exposed to the sun. This posture helps reduce heat gain by radiation.

43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Adjusting Metabolic Heat Production Some animals can regulate body temp by adjusting their metabolic heat production rate Many flying insect species use shivering to warm up before taking flight Figure 40.20 Preflight warmup in the hawkmoth. The hawkmoth (Manduca sexta) is one of many insect sp that use a shivering-like mechanism for preflight warmup of thoracic flight muscles. Warming up helps these muscles produce enough power to let the animal take off. Once airborne, flight muscle activity maintains a high thoracic temp.

44. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Mammals regulate temp by a complex negative feedback system that involves several organ systems – Humans: a specific part of the brain, the hypothalamus contains a group of nerve cells that ftn as a thermostat Feedback Mechanisms in Thermoregulation Figure 40.21 The thermostat ftn of the hypothalamus in human thermoregulation.

45. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Adjustment to Changing Temperatures Acclimatization – many animals can adjust to a new range of environmental temps over a period of days or weeks – It may involve cellular adjustments – Or in the case of birds & mammals, adjustments of insulation/metabolic heat production

46. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Torpor and Energy Conservation Torpor - an adaptation that enables animals to save E while avoiding difficult/dangerous conditions – Physiological state-activity is low/metabolism decreases Hibernation is long-term torpor – = an adaptation to winter cold & food scarcity during which the animal’s body temperature declines

47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 40.22 Body temperature and metabolism during hibernation in Belding’s ground squirrels.

48. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Estivation (summer torpor) enables animals to survive long periods of hi temp & scarce water supply Daily torpor is exhibited by many small mammals and birds and seems to be adapted to their feeding patterns