1. Basic Principles of Animal Form and Function
Chapter 32 – Part I
Basic Principles of Animal Form and Function

2. What you must know:
How feedback systems function to maintain homeostasis
One example of positive feedback and one example of negative feedback

3. Diverse Forms, Common Challenges
Anatomy: the study of the biological form (STRUCTURE) of an organism
Physiology: the study of the biological FUNCTIONS an organism performs
Structure dictates function!

5. Animal form and function are correlated at all levels of organization
Size and shape affect the way an animal interacts with its environment
Many different animal body plans have evolved and are determined by the genome

6. Hierarchical Organization of Body Plans
Cells  Tissues  Organs  Organ Systems

7. Four main types of tissues:
Epithelial: covers the outside of the body and lines the organs and cavities within the body
Connective: binds and supports other tissues (cartilage, tendons, ligaments, bone, blood, adipose)
Muscle: controls body movement (skeletal, smooth, cardiac)
Nervous: senses stimuli and transmits signals throughout the animal (neurons, glia)

13. Coordination and control within a body
Endocrine System: transmits chemical signals (hormones) to all locations in the body through the bloodstream
Slow acting, long-lasting effects
Info received by: cells with specific receptors for released hormone
Nervous System: neurons transmit info between specific locations
Very fast!
Info received by: neurons, muscle cells, endocrine cells

14. Homeostasis
Maintain a “steady state” or internal balance regardless of external environment
Fluctuations above/below a set point serve as a stimulus; these are detected by a sensor and trigger a response
The response returns the variable to the set point

16. Negative Feedback Positive Feedback
“More gets you less.”
Return changing conditions back to set point
Examples:
Temperature
Blood glucose levels
Blood pH
Plants: response to water limitations
“More gets you more.”
Response moves variable further away from set point
Stimulus amplifies a response
Examples:
Lactation in mammals
Onset of labor in childbirth
Plants: ripening of fruit

17. Temperature Regulation

18. Thermoregulation
Maintain an internal temperature within a tolerable range
Endothermic animals generate heat by metabolism (birds and mammals)
Ectothermic animals gain heat from external sources (invertebrates, fishes, amphibians, and nonavian reptiles)
Q: Which is more active at greater temperature variations?
Q: Which requires more energy?

21. Energy Use
Metabolic rate: total amount of energy an animal uses in a unit of time
Ectotherms have much lower metabolic rates than endotherms of a comparable size

22. Metabolic rate is inversely related to body size among similar animals

23. Balancing Heat Loss and Gain
Organisms exchange heat by four physical processes: radiation, evaporation, convection, and conduction

24. Five adaptations for thermoregulation:
Insulation (skin, feather, fur, blubber)
Circulatory adaptations (countercurrent exchange)
Cooling by evaporative heat loss (sweat)
Behavioral responses (shivering)
Cellular adjustments (“antifreeze” proteins, membrane lipids, enzyme variants)

25. Countercurrent heat exchange

27. Torpor and Energy Conservation
Torpor is a physiological state in which activity is low and metabolism decreases
Save energy while avoiding difficult and dangerous conditions
Hibernation: torpor during winter cold and food scarcity
Estivation: summer torpor, survive long periods of high temperatures and scarce water

29. Marine vs. Freshwater Fish
Osmoregulation
Marine vs. Freshwater Fish
Nitrogenous wastes

30. Mammalian Excretory System
Osmoregulation
Mammalian Excretory System

31. Nephron: blood filtration and water concentration in the human kidney