Ch. 40 Warm up

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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.

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Chapter 40
Basic Principles of Animal Form and Function
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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
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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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Hierarchical Organization of Body Plans

• Cells ? Tissues ? Organs ? Organ Systems

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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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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

• 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

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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
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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
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Figure 40.16
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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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Figure 40.19
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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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