1. Basic Principles of Animal Form and Function
Chapter 40
Basic Principles of Animal Form and Function

2. Overview: 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!
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3. How does a jackrabbit keep from overheating?
Figure 40.1
Figure 40.1 How does a jackrabbit keep from overheating? 4

4. 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
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5. Hierarchical Organization of Body Plans
Cells  Tissues  Organs  Organ Systems
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6. 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)
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11. Coordination and Control Within a Body
Endocrine system: transmits chemical signals (hormones) to receptive cells throughout body via blood
Slow acting, long-lasting effects
Nervous system: neurons transmit info between specific locations
Very fast!
Info received by: neurons, muscle cells, endocrine cells
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13. 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
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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
Amoeba Sisters: Homeostasis and Feedback Mechanisms

17. HOMEWORK
Watch Dr. Anderson’s video on Feedback Loops and complete the question sheet.

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?
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19. Figure 40.10
Figure Endothermy and ectothermy. 20

20. Balancing Heat Loss and Gain
Organisms exchange heat by four physical processes: radiation, evaporation, convection, and conduction
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21. Five adaptations for thermoregulation:
Insulation (skin, feather, fur, blubber)
Circulatory adaptations (countercurrent exchange)
Cooling by evaporative heat loss (sweat)
Behavioral responses (shivering)
Adjusting metabolic heat production (“antifreeze”)
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22. Figure 40.12
Figure Countercurrent heat exchangers. 23

23. Figure 40.16
Figure The thermostatic function of the hypothalamus in human thermoregulation. 24

24. Energy Use
Metabolic rate: amount of energy an animal uses in a unit of time
Basal metabolic rate (BMR): endotherm at rest at a “comfortable” temperature
Standard metabolic rate (SMR): ectotherm at rest at a specific temperature
Ectotherms have much lower metabolic rates than endotherms of a comparable size
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25. Larger animals produce more oxygen/hr (greater metabolism)…
Figure 40.19
Larger animals produce more oxygen/hr (greater metabolism)…
But the amount of oxygen/hr/kg is much higher in smaller animals
Figure The relationship of metabolic rate to body size. 26

26. 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
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