Chapter 40: Basic Principles of Animal Form & Function

Chapter 40: Basic Principles of Animal Form & Function (a) Tuna (b) Shark (c) Penguin (d) Dolphin (e) Seal Evolutionary convergence in fast swimmers

Chapter 40: Basic Principles of Animal Form & Function 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 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

Chapter 40: Basic Principles of Animal Form & Function How has exchange with the environment evolved? Simple diffusion from direct contact w/ environment To internal exchange thru moist medium Reminder…what is the hierarchy of biological organization? Atomsmoleculesorganellescellstissuesorgansorgan systems… What is a tissue & what are the 4 types? Group of cells in a matrix with a common structure & function Epithelial Connective Muscular Nervous

Stratified squamous epithelia Simple squamous epithelia EPITHELIAL TISSUE Columnar epithelia, which have cells with relatively large cytoplasmic volumes, are often located where secretion or active absorption of substances is an important function. A stratified columnar epithelium A simple columnar A pseudostratified ciliated columnar Stratified squamous epithelia Simple squamous epithelia Cuboidal epithelia Basement membrane 40 µm Epithelial Tissue Tightly packed sheets that cover the body, line organs & cavities w/in the body Involved with secretion & absorption

Fibrous connective tissue Collagenous fiber Elastic Chondrocytes Chondroitin sulfate Loose connective tissue Fibrous connective tissue 100 µm 100 µm Nuclei 30 µm Bone Blood Central canal Osteon 700 µm 55 µm Red blood cells White blood cell Plasma Cartilage Adipose tissue Fat droplets 150 µm CONNECTIVE TISSUE Connective Tissue Binds & supports other tissues 3 types Collagenous non-elastic – skin won’t rip Elastic elastin – skin reshapes Reticular Thin & branched Made of collagen Joins connective tissue to neighboring tissue

Long cells made of contractile proteins Actin & myosin 3 kinds MUSCLE TISSUE Skeletal muscle 100 µm Multiple nuclei Muscle fiber Sarcomere Cardiac muscle Nucleus Intercalated disk 50 µm Smooth muscle Muscle fibers 25 µm NERVOUS TISSUE Neurons Process Cell body Muscle tissue (ch 49) Long cells made of contractile proteins Actin & myosin 3 kinds Skeletal – aka striated (w/ lines) Cardiac – heart – branched cells Smooth no striations In walls of digestive tract, bladder, arteries Nervous tissue (ch 48) Sense stimuli & transmits signals neuron

Chapter 40: Basic Principles of Animal Form & Function 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 – breaks bonds – releases energy – exergonic Anabolism – forms bonds – requires energy – endergonic

Figure 40.7 Bioenergetics of an animal: an overview Organic molecules in food Digestion and absorption Nutrient molecules in body cells Cellular respiration Biosynthesis: growth, storage, and reproduction work Heat Energy lost in feces urine External environment Animal body Carbon skeletons ATP

Chapter 40: Basic Principles of Animal Form & Function 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 – breaks bonds – releases energy – exergonic Anabolism – forms bonds – requires energy – endergonic 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 Room temperature decreases Heater turned off Set point Too hot Set point Control center: thermostat increases on cold Heat Set point is maintained

Chapter 40: Basic Principles of Animal Form & Function 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 – breaks bonds – releases energy – exergonic Anabolism – forms bonds – requires energy – endergonic 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 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 River otter (endotherm) Largemouth bass (ectotherm) Ambient (environmental) temperature (°C) Body temperature (°C) 40 30 20 10

Chapter 40: Basic Principles of Animal Form & Function 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 do organisms exchange heat with their environment?

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.

Chapter 40: Basic Principles of Animal Form & Function 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 do organisms exchange heat with their environment? How can organisms exchange heat within their bodies? - Countercurrent heat exchange

Figure 40.15 Countercurrent heat exchangers 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. 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. 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. Canada goose Artery Vein 35°C Blood flow 30º 20º 10º 33° 27º 18º 9º Pacific bottlenose dolphin 1 2 3

Chapter 40: Basic Principles of Animal Form & Function 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 do organisms exchange heat with their environment? How can organisms exchange heat within their bodies? How do we achieve homeostasis for body temperature?

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

Chapter 40: Basic Principles of Animal Form & Function 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 do organisms exchange heat with their environment? How can organisms exchange heat within their bodies? How do we achieve homeostasis for body temperature? 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 200 Actual metabolism 100 Metabolic rate (kcal per day) Arousals 35 Body temperature 30 25 20 Temperature (°C) 15 10 5 Outside temperature -5 Burrow temperature -10 -15 June August October December February April