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Chapter 32 An Introduction to Animal Diversity 1. What is an animal? - Multicellular, heterotrophic eukaryote – ingestion - Structural support from structural proteins – NOT cell walls - Nervous tissue & muscle tissue for impulse conduction & movement - Sexual reproduction with motile sperm swimming to non-motile egg Chapter 40: Basic Principles of Animal Form & Function 1. What is an animal? 2. How has exchange with the environment evolved? - Simple diffusion from direct contact w/ environment - To internal exchange thru moist medium Figure 40.3 Contact with the environment Mouth Diffusion Gastrovascular cavity Diffusion Diffusion (a) Single cell (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) 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). Chapter 40: Basic Principles of Animal Form & Function 1. What is an animal? 2. How has exchange with the environment evolved? - Simple diffusion from direct contact w/ environment - To internal exchange thru moist medium 3. Reminder…what is the hierarchy of biological organization? Atomsmoleculesorganellescellstissuesorgansorgan systems… 4. What is a tissue & what are the 4 types? - Group of cells in a matrix with a common structure & function - Epithelial - Tightly packed sheets that cover the body, line organs & cavities w/in the body - - - - Involved with secretion & absorption Connective - Binds & supports other tissues - 3 kinds - collagenous, elastic, reticular Muscular - Long cells made of contractile proteins (actin & myosin) - 3 kinds - skeletal, smooth, cardiac Nervous - Sense stimuli & transmits signals - Neuron – basic unit/cell Chapter 40: Basic Principles of Animal Form & Function 1. 2. 3. 4. 5. What is an animal? How has exchange with the environment evolved? Reminder…what is the hierarchy of biological organization? What is a tissue & what are the 4 types? What is metabolism? - All of the chemical rxns within an organism - Catabolism – hydrolysis breaks bonds – releases energy – exergonic - Anabolism – dehydration rxns forms bonds – requires energy – endergonic Figure 40.7 Bioenergetics of an animal: an overview Organic molecules in food External environment Animal body Digestion and absorption Heat Nutrient molecules in body cells Carbon skeletons Cellular respiration Energy lost in feces Energy lost in urine Heat ATP Biosynthesis: growth, storage, and reproduction Heat Cellular work Heat Chapter 40: Basic Principles of Animal Form & Function 1. 2. 3. 4. 5. What is an animal? How has exchange with the environment evolved? Reminder…what is the hierarchy of biological organization? What is a tissue & what are the 4 types? What is metabolism? - All of the chemical rxns within an organism - Catabolism – hydrolysis breaks bonds – releases energy – exergonic - Anabolism – dehydration rxns forms bonds – requires energy – endergonic 6. What is homeostasis & how is it achieved? - Steady state - Negative feedback - the response is in the opposite direction of the stimulus Figure 40.11 A nonliving example of negative feedback: control of room temperature Response No heat produced Heater turned off Room temperature decreases Set point is maintained Too hot Set point Too cold Set point Set point Control center: thermostat Room temperature increases Heater turned on Response Heat produced Chapter 40: Basic Principles of Animal Form & Function 1. 2. 3. 4. 5. 6. What is an animal? How has exchange with the environment evolved? Reminder…what is the hierarchy of biological organization? What is a tissue & what are the 4 types? What is metabolism? What is homeostasis & how is it achieved? - Steady state - Negative feedback - the response is in the opposite direction of the stimulus - Positive feedback - Response & stimulus are in the same direction 7. What are the 2 types of thermoregulation? - Ectothermic – heat & metabolism based on environment - Endothermic – heat & metabolism regulated internally 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) 40 Chapter 40: Basic Principles of Animal Form & Function 1. 2. 3. 4. 5. 6. 7. What is an animal? How has exchange with the environment evolved? Reminder…what is the hierarchy of biological organization? What is a tissue & what are the 4 types? What is metabolism? What is homeostasis & how is it achieved? What are the 2 types of thermoregulation? Chapter 40: Basic Principles of Animal Form & Function 1. 2. 3. 4. 5. 6. 7. 8. What is an animal? How has exchange with the environment evolved? Reminder…what is the hierarchy of biological organization? What is a tissue & what are the 4 types? What is metabolism? What is homeostasis & how is it achieved? What are the 2 types of thermoregulation? How can organisms exchange heat within their bodies? - Countercurrent heat exchange Figure 40.15 Countercurrent heat exchangers 1 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. Canada goose Artery 1 35°C 30º 2 Near the end of the leg or flipper, where arterial blood has been cooled to far below the animal’s core temperature, the artery Vein can still transfer heat to the even colder 3 blood of an adjacent vein. The venous blood 33° continues to absorb heat as it passes warmer and warmer arterial blood traveling in the opposite direction. 27º 20º 18º 10º 9º 2 Pacific bottlenose dolphin 1 3 Blood flow 3 Vein Artery 2 3 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. 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. Chapter 40: Basic Principles of Animal Form & Function 1. 2. 3. 4. 5. 6. 7. 8. 9. What is an animal? How has exchange with the environment evolved? Reminder…what is the hierarchy of biological organization? What is a tissue & what are the 4 types? What is metabolism? What is homeostasis & how is it achieved? What are the 2 types of thermoregulation? How can organisms exchange heat within their bodies? How do we achieve homeostasis for body temperature? 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. Thermostat in hypothalamus activates warming mechanisms. Chapter 40: Basic Principles of Animal Form & Function 1. What is an animal? 2. How has exchange with the environment evolved? 3. Reminder…what is the hierarchy of biological organization? 4. What is a tissue & what are the 4 types? 5. What is metabolism? 6. What is homeostasis & how is it achieved? 7. What are the 2 types of thermoregulation? 8. How do organisms exchange heat with their environment? 9. How do we achieve homeostasis for body temperature? 10. How do animals thermoregulate in temperature extremes? - Torpor – physiological state in which activity is low & metabolism is decreased - Hibernation – winter – bears, Belding’s ground squirrels - Estivation – summer – many reptiles, bees Figure 40.22 Body temperature and metabolism during hibernation in Belding’s ground squirrels Additional metabolism that would be necessary to stay active in winter Temperature (°C) Metabolic rate (kcal per day) 200 Actual metabolism 100 0 35 30 25 Arousals Body temperature 20 15 10 5 0 -5 -10 -15 Outside temperature June August Burrow temperature October December February April