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 What you need to know… The 4 types of tissues and their general functions. The importance of homeostasis and examples. How feedback systems control homeostasis, and one example of positive feedback and one example of negative feedback.

3. 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 The comparative study of animals reveals that form and function are closely correlated Figure 40.1

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 40.1 Basic Principles of Animal Form and Function Physical laws and the need to exchange materials with the environment – Place certain limits on the range of animal forms The ability to perform certain actions – Depends on an animal’s shape and size

5. 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 (a) Tuna (b) Shark (c) Penguin (d) Dolphin (e) Seal

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Exchange with the Environment An animal’s size and shape – Have a direct effect on how the animal exchanges energy and materials with its surroundings Exchange with the environment occurs as substances dissolved in the aqueous medium – Diffuse and are transported across the cells’ plasma membranes

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A single-celled protist living in water – Has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm Figure 40.3a Example of Form and Function Diffusion (a) Single cell

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Example of Form and Function Multicellular organisms with a sac body plan – Have body walls that are only two cells thick, facilitating diffusion of materials Figure 40.3b Mouth Gastrovascular cavity Diffusion (b) Two cell layers

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Levels of Organization Tissues – groups of cells that have a common structure and function Organs – functional units of tissues Organ Systems – groups of organs that work together (ex. Digestive, circulatory, or excretory systems)

10. 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 – The tissues are arranged in layers Figure 40.6

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Types of Tissues 4 Types of tissues – Epithelial tissue – Connective tissue – Muscle tissue – Nervous tissue

12. 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 – Contains cells that are closely joined

13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Connective Tissue – Functions mainly to bind and support other tissues – Contains sparsely packed cells scattered throughout an extracellular matrix

14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Muscle Tissue – Is composed of long cells called muscle fibers capable of contracting in response to nerve signals – Is divided in the vertebrate body into three types: skeletal, cardiac, and smooth

15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Nervous Tissue – Senses stimuli and transmits signals throughout the animal, including to other neurons (nerve cells), glands, muscles, and the brain.

16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organ Systems in Mammals

17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2 Systems that Specialize Coordination and Control For survival, tissues, organs, and organ systems must act in a coordinated way: 2 Systems specialize in this: 1.Endocrine system – chem. Signals called hormones = released. Each hormone cause specific effects 2.Nervous system (neurons) – transmit info between specific locations

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The internal environment of vertebrates – Is called the interstitial fluid, and is very different from the external environment Homeostasis - a balance between external changes and the animal’s internal control mechanisms that oppose the changes 40.2 Feedback control loops maintain homeostasis

19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Homeostatic Control Functions by having a set point (like a body temp to maintain) – It has sensors to detect any stimulus above or below the set point – A physiological response helps return the body to its set point 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

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Homeostatic Control Systems – Negative feedback systems (most) – Where buildup of the end product of the system shuts the system off Ex. In response to exercise, the body temp rises, which initiates sweating to cool the body

21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Homeostatic Control Systems – Positive feedback systems involves a change in some variable that triggers mechanisms to amplify the change Ex. During birth, pressure of the baby’s head against receptors near the opening of the uterus stimulates greater uterine contractions, which cause greater pressure against the uterine opening, which heightens the contractions and so forth

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 40.3 Homestatic processes for thermoregulation Thermoregulation – process by which animals maintain an internal temperature within a tolerable range – 2 Types of regulation Endotherms – (such as mammals and birds) – warmed mostly by heat generated by metabolism Ectotherms – (such as most invertebrates, fishes, amphibians, and reptiles) – generate relatively little metabolic heat, gaining most of their heat from external sources

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

24. 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 Endoderms

25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Modes of 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

26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Balancing Heat Loss and Gain Thermoregulation involves physiological and behavioral adjustments – That balance heat gain and loss – Examples include Insulation Vasodilation Vasocontriction Countercurrent Exchange

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Balancing Heat Loss and Gain Insulation – Reduces the flow of heat between an animal and its environment – May include feathers, fur, or blubber In vasodilation – Blood flow in the skin increases, facilitating heat loss In vasoconstriction – Blood flow in the skin decreases, lowering heat loss

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Many marine mammals and birds – Have arrangements of blood vessels called countercurrent heat exchangers that are important for reducing heat loss – Antiparallel blood vessels going from the middle of the body where the blood is warm to the extremities Countercurrent Exhange 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

29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Countercurrent Heat Exhange Some specialized 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.

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Countercurrent Heat Exchange Many endothermic insects – Have countercurrent heat exchangers that help maintain a high temperature in the thorax Figure 40.17

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Adjustment to Changing Temperatures In a process known as acclimatization – Many animals can adjust to a new range of environmental temperatures over a period of days or weeks

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Torpor and Energy Conservation Torpor – Is an adaptation that enables animals to save energy while avoiding difficult and dangerous conditions – Is a physiological state in which activity is low and metabolism decreases

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hibernation is long-term torpor – That is an adaptation to winter cold and food scarcity during which the animal’s body temperature declines 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

34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Estivation, or summer torpor – Enables animals to survive long periods of high temperatures and scarce water supplies Daily torpor – Is exhibited by many small mammals and birds and seems to be adapted to their feeding patterns