1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings IB202-8 3-31-06 Form and Function Chapt 40 (all) Read ahead in Chpt 41 for next week

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overview: Diverse Forms, Common Challenges Animals inhabit almost every part of the biosphere AND despite their amazing diversity they all face a similar set of problems including how to nourish themselves, gas exchange, waste removal and reproduction.

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Nectar sucking sphinx moth (long proboscis) The comparative study of animals – Reveals that form and function are closely correlated. Natural selection can fit structure (anatomy) to function (physiology) by selecting over many generations, what works best among the available variations in a population. Figure 40.1

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Physical laws and the environment constrain animal size and shape Physical laws and the need to exchange materials with the environment also place limits on the range of animal forms and structures. For example: the ability to perform certain actions depends on an animal’s shape and size. An elephant needs certain sized legs to support its massive weight. The next slide shows a convergence of the body plan (fusiform shape) of fast swimming fish, sharks, penguins and dolphins.

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 Tuna speed 80 km/hr. Anglar Fish-large head, wait and gulp predator

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Exchange with the Environment An animal’s size and shape has a direct effect on how the animal exchanges materials with its surroundings Exchange with the environment occurs as substances dissolved in the aqueous medium that surrounds cells. As an example the oxygen in the air we breath is dissolved in a thin layer of water on the surface of the aveolar cells (thin walled terminal compartments in the lung where gas exchange occurs)). Gases and organic molecules diffuse into aqueous layer and are transported across the cells’ plasma membranes into the cytoplasm or the blood. Importance of distance in diffusion. Time for a molecule to diffuse through tissues increases as the square of the distance. 1um--10 -4 seconds, 10um--10 -2 sec, 1 mm --100 sec, 10 mm—3hrs. Thus distances must be small.

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 by simple diffusion – Figure 40.3a Diffusion (a) Single cell 50um

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Multicellular organisms with a sac body plan – Have body walls that are only two cells thick and again the distances are small enough so that diffusion is adequate. Figure 40.3b Mouth Gastrovascular cavity Diffusion (b) Two cell layers

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organisms with more complex body plans and especially large organisms have evolved specialized organs and surfaces for exchanging gas and nutrients. Where the plumbing has reduced the diffusion distance between fluid compartments. The next slide shows an example of a vertebrate illustrating the systems involved:

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings External environment FoodCO 2 O2O2 Mouth Animal body Respiratory system Circulatory system Nutrients Excretory System—glomerular cappilaries Digestive system 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 Figure 40.4

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 40.2: Animal form and function are correlated at all levels of organization Animals are composed of cells Groups of cells with a common structure and function – Make up tissues Different tissues make up organs – Which together make up organ systems

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

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

14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Epithelial tissue 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 epithelium A pseudostratified ciliated columnar epithelium Stratified squamous epithelia Simple squamous epithelia Cuboidal epithelia Basement membrane 40 µm Figure 40.5 Lungs KiKiKiKi Kidney Esophagus Vagina, skin Lines airways, note cilia Intestinal lining Lines urethera

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

16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Collagenous fiber Elastic fiber Chondrocytes Chondroitin sulfate Loose connective tissue Fibrous connective tissue 100 µm Nuclei 30 µm Bone Blood Central canal Osteon 700 µm55 µm Red blood cells White blood cell Plasma Cartilage Adipose tissue Fat droplets 150 µm CONNECTIVE TISSUE Connective tissue Figure 40.5

17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Muscle Tissue 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, (striated muscle) – cardiac, (heart cells electrically connected) – Smooth (non striated, slow contractions)

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Nervous Tissue Nervous tissue – Senses stimuli and transmits signals throughout the animal – Incorporate into figure

19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Muscle and nervous tissue MUSCLE TISSUE Skeletal muscle 100 µm Multiple nuclei Muscle fiber Sarcomere Cardiac muscle Nucleus Intercalated disk 50 µm Smooth muscle Nucleus Muscle fibers 25 µm NERVOUS TISSUE Neurons Process Cell body Nucleus 50 µm Figure 40.5

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organs and Organ Systems In all but the simplest animals – Different tissues are organized into organs

21. 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 all but the simplest animals different tissues are organized into organs. In some organs the tissues are arranged in layers Organs Figure 40.6

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organ Systems Representing a level of organization higher than organs – Organ systems carry out the major body functions of most animals

23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organ systems in mammals Table 40.1

24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 40.3: Animals use the chemical energy in food to sustain form and function All organisms require chemical energy for – Growth, repair, physiological processes, regulation, and reproduction The flow of energy through an animal, its bioenergetics ultimately limits the animal’s behavior, growth, and reproduction determines how much food it needs Studying an animal’s bioenergetics – Tells us a great deal about the animal’s adaptations or “life style”. (Endotherm vs ectotherm).

25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy Sources and Allocation Animals harvest chemical energy from the food they eat Once food has been digested most of the energy-containing molecules are used to make ATP, which powers cellular work. Generation of ATP requires oxygen and produces CO 2

26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings After the energetic needs of staying alive are met ie. Ion transport, muscle contraction heat production any remaining molecules from food can be used in biosynthesis or stored in the form of lipid or carbohydrate Figure 40.7 Organic molecules in food Digestion and absorption Nutrient molecules in body cells Cellular respiration Biosynthesis: growth, storage, and reproduction Cellular work Heat Energy lost in feces Energy lost in urine Heat External environment Animal body Heat Carbon skeletons ATP Oxidation of reduced carbon (CH 2 )-  ATP+CO 2 Carbohydrates, proteins and lipids Muscle contraction Oxygen

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings An animal’s metabolic rate – Is the amount of energy an animal uses in a unit of time and can be measured in a variety of ways – Most common way is measuring oxygen consumption both in the resting and active states. Another less well known way is to measure heat production. (Requires elaborate equipment). Quantifying Energy Use

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings One way to measure metabolic rate – Is to determine the amount of oxygen consumed or carbon dioxide produced by an organism Figure 40.8a, b This photograph shows a ghost crab in a respirometer. Temperature is held constant in the chamber, with air of known O 2 concentration flow- ing through. The crab’s metabolic rate is calculated from the difference between the amount of O 2 entering and the amount of O 2 leaving the respirometer. This crab is on a treadmill, running at a constant speed as measurements are made. (a) (b) Similarly, the metabolic rate of a man fitted with a breathing apparatus is being monitored while he works out on a stationary bike.

29. 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, meaning that their bodies are warmed mostly by heat generated by metabolism. They typically have higher metabolic rates. Amphibians and reptiles other than birds are ectothermic, meaning that they gain their heat mostly from external sources. Thus they have lower metabolic rates. Bioenergetic Strategies

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The metabolic rates of animals are affected by many factors: Metabolic rate per gram – Is inversely related to body size among similar animals. Smaller animals have higher metabolic rate both in endotherms and ectotherms. In the case of endotherms a greater surface to volume ration might explain this relationship, but it is also present in ectotherms that assume the temperature of the environment. Effect not presently explained. Size Influences Metabolic Rate

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The basal metabolic rate (BMR) – Is the metabolic rate of an endotherm at rest The standard metabolic rate (SMR) – Is the metabolic rate of an ectotherm at rest For both endotherms and ectotherms – Activity has a large effect on metabolic rate Activity and Metabolic Rate

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Different species of animals – Use the energy and materials in food in different ways, depending on their environment Energy Budgets

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings An animal’s use of energy – Is partitioned to BMR (or SMR), activity, homeostasis, growth, and reproduction Endotherms Ectotherm Annual energy expenditure (kcal/yr) 800,000 Basal metabolic rate Reproduction Temperature regulation costs Growth Activity costs 60-kg female human from temperate climate Total annual energy expenditures (a) 340,000 4-kg male Adélie penguin from Antarctica (brooding) 4,000 0.025-kg female deer mouse from temperate North America 8,000 4-kg female python from Australia Energy expenditure per unit mass (kcal/kgday) 438 Deer mouse 233 Adélie penguin 36.5 Human 5.5 Python Energy expenditures per unit mass (kcal/kgday) (b) Figure 40.10a, b