Evolutionary Convergence in Fast Swimmers

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

2. 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

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

4. External environment Food CO2 O2 Mouth Animal body Respiratory system Blood 50 µm 0.5 cm 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). Cells Heart Nutrients Circulatory system 10 µm Interstitial fluid Digestive system Excretory system 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). Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM). Anus Unabsorbed matter (feces) Metabolic waste products (urine) Figure 40.4 Internal exchange surfaces of complex animals

5. 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

6. 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 simple columnar epithelium A pseudostratified ciliated columnar epithelium A stratified columnar epithelium Stratified squamous epithelia Cuboidal epithelia Simple squamous 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

7. CONNECTIVE TISSUE 100 µm Chondrocytes Collagenous fiber Chondroitin sulfate Elastic fiber 100 µm Cartilage Loose connective tissue Adipose tissue Fibrous connective tissue Fat droplets Nuclei 150 µm 30 µm Blood Bone Central canal Red blood cells White blood cell Osteon Plasma 700 µm 55 µm • 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

8. MUSCLE TISSUE 100 µm Skeletal muscle Multiple nuclei Muscle fiber Sarcomere Cardiac muscle 50 µm Intercalated disk Nucleus Nucleus Smooth muscle Muscle fibers 25 µm NERVOUS TISSUE Process Neurons Cell body Nucleus 50 µm • 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

9. 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

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

11. 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

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

13. 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

14. 40 River otter (endotherm) 30 Body temperature (°C) 20 Largemouth bass (ectotherm) 10 0 10 20 30 40 Ambient (environmental) temperature (°C) Figure 40.12 The relationship between body temperature and environmental temperature in an aquatic endotherm and ectotherm

15. 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?

16. 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.

17. 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

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

19. 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?

20. Sweat glands secrete sweat that evaporates, cooling the body. Thermostat in hypothalamus activates cooling mechanisms. Blood vessels in skin dilate: capillaries fill with warm blood; heat radiates from skin surface. Increased body temperature (such as when exercising or in hot surroundings) Body temperature decreases; thermostat shuts off cooling mechanisms. Homeostasis: Internal body temperature of approximately 36–38C 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. Thermostat in hypothalamus activates warming mechanisms. Skeletal muscles rapidly contract, causing shivering, which generates heat. Figure 40.21 The thermostat function of the hypothalamus in human thermoregulation

21. 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

22. 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) 0 Arousals 35 Body temperature 30 25 20 Temperature (°C) 15 10 5 Outside temperature 0 Burrow temperature -5 -10 -15 June August October December February April