Ch. 40 Warm up

1. Define and give an example of homeostasis.

2. Sequence the organization of living things from cell to biome.

3. Describe negative and positive feedback.

LECTURE PRESENTATIONSFor CAMPBELL BIOLOGY, NINTH EDITION

Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson

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Lectures byErin Barley

Kathleen Fitzpatrick

Basic Principles of Animal Form and Function

Chapter 40

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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Figure 40.1

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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• Cells Tissues Organs Organ Systems

Hierarchical Organization of Body Plans

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Four main types of tissues:

1. Epithelial: covers the outside of the body and lines the organs and cavities within the body

2. Connective: binds and supports other tissues (cartilage, tendons, ligaments, bone, blood, adipose)

3. Muscle: controls body movement (skeletal, smooth, cardiac)

4. Nervous: senses stimuli and transmits signals throughout the animal (neurons, glia)

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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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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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Negative Feedback

• “More gets you less.”• Return changing conditions

back to set point• Examples:

– Temperature

– Blood glucose levels

– Blood pH

Plants: response to water limitations

Positive Feedback

• “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

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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Figure 40.10

Balancing Heat Loss and Gain

• Organisms exchange heat by four physical processes: radiation, evaporation, convection, and conduction

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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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Figure 40.12

Figure 40.16

• 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

Energy Use

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Figure 40.19

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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