Chapter 1: ANIMALS AND ENVIRONMENT

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  1. Animals and Environments: Function on the Ecological Stage
  2. Physiology is the integrated study of how biological systems work
  3. Organization of Book (Table 1.1)
  4. Conformity and Regulation
    1. When faced with change, an organism can either conform to the change or regulate the internal environment
  5. Conformers (Figure 1.6a)
    1. Benefits
  6. Conformers (Figure 1.6a)
    1. Costs
  7. Regulators (Figure 1.6b)
    1. benefits
    2. costs
  8. Example: Migrating Pacific salmon (Fig 1.1)
  9. Mixed conformity and regulation in a single species  (Figure 1.7)
    1. temperature
    2. salinity
  10. The Idea of Homeostasis
    1. Claude Bernard and W. B. Cannon
    2. negative feedback
    3. positive feedback
  11. The idea of homeostasis
    1. Maintaining and monitoring internal versus external environments
  12.  Homeostasis requires regulation via Negative Feedback control
    1. Examples
  13. Positive Feedback
  14. Physiological traits are genetically determined, environmentally determined, or combination of both
  15. The five time frames in which physiology changes (Table 1.2)
  16. What are the Physiological change timescales in response to external environment? Part 1
    1. EVOLUTIONARY
      1. Adjustment of physiology to environmental conditions in populations across generations
      2. Adaptation
        1. physiological, biochemical, or anatomical modifications occurring within a species that facilitate an enhanced ability to survive and reproduce in a particular environment,
      3. Irreversible change in genotype
  17. What are the Physiological change timescales in response to external environment? Part 2
    1.  Within individuals
      1. Short term or ACUTE: no change in gene expression,
      2. Long term or CHRONIC changes: Physiology adapts to environmental change
        1. Reversible
  18. LONG TERM or CHRONIC Physiological change
    1. Phenotypic plasticity
  19. Phenotypic Plasticity
    1. Acclimatization
      1. physiological, biochemical, or anatomic change within an individual animal during its life
      2. change in gene expression
    2. Acclimation: same process except initiated by an investigator  
  20. Heat acclimation in humans as measured by exercise endurance (Figure 1.8)
    1. Acute response
    2. Chronic response
  21. Physics and Chemistry
    1. Physical properties are linked to function (e.g., bone)
    2. Chemical laws govern molecular interactions
    3. Electrical laws describe membrane function
    4. Body size influences biochemical and physical patterns
  22. Body Size and Scaling:  Size Matters in Physiology
  23. Living Organisms Come in a Huge Range of Sizes
  24. Length of gestation scales as a regular function of body size in mammals (Fig 1.9)
    1. Appendix D-F Fitting lines to data
    2. Least squares regression
  25. Isometric Growth: proportional growth
  26. Isometric change
    1. each dimension is scaled up or down the same amount
    2. disproportionate change can still occur in parameters such as surface area and volume
    3. The proportions remain constant and do not change with a change in size.
  27. Equiangular spiral growth
  28. Allometric Growth
    1. Changes in body proportions
  29. Allometric growth
    1. Different rates of growth of different parts at different stages
    2. Proportions adjust to the different rates at which surface area, volume, and other physical parameters change
    3. Allometry: A good introduction from Jim Moore, Anthropology, UCSD. 
  30. Body Size Profoundly Influences Physiology
    1. Gravity, Circulation, Movement and Locomotion
  31. Bone shape changes with increasing body size.
  32. Size in the Life of Animals
    1. Sizes of Organisms: The Surface Area to Volume Ratio  from Monica Beals and Louis Gross, the Institute for Environmental Modeling, University of Tennessee, Knoxville
      1. SA/V α r2/3
      2. exponential equation
    2. Tutorial for Size and Shape in Biology developed at the University of Chicago by Thomas Colton
  33. Surface to volume ratio
  34. Allometric Equation
    1. Y = aXb
    2. Y = variable being measured in relationship to the size of the organism
    3. X = measure of size used for basis of comparison, usually a measure of whole body size
  35. Allometric data can also be expressed as linear functions of Log-Transformed Data
    1. log Y = log a + b log X  (Fig. 1.9)
  36. Allometric Equation
    1. Y = aXb
    2. a = initial growth index, a constant
  37. Allometric Equation
    1. Y = aXb
    2. b = scaling exponent: proportional change in Y per unit X
  38. Allometry in Physiology
    1. X is often a meaure of size, usually M, mass
  39. Example: Total MR = 0.676*Mb0.75
  40. The Scaling Exponent (b) Defines the Type of Scaling Relationship Y
    1.  If b = 1, there is no differential growth:  isometry (geometric similarity)
    2. If b < 1, Y increases more slowly than X: negative allometry
    3. If b > 1, positive allometryy
    4. This is true only if like dimensions (e.g. length to length, mass to mass) are being compared.
  41. b = 1, isometry,
  42. b < 1, negative allometry,
  43. b > 1, positive allometry
  44. Examples of Isometry for Different Dimensions
    1. Linear dimensions
      1. Head Length vs. Body Length;  Isometry, b = 1
  45. Examples of Isometry for Different Dimensions
    1. Linear versus cubic dimensions
      1. Head Length vs. Body Mass;  Isometry:  b = 1/3 = 0.33
      2. Body Mass vs. Head Length;  Isometry:  b = 3/1 = 3
      3.  scaling
      4. Determining if a system is scaling with allometry
  46. Examples of Isometry for Different Dimensions
    1. Square versus cubic dimensions
      1. Surface Area vs. Body Mass;   Isometry: b = 2/3 = 0.67
  47. Isometric scaling on a cube.
    1. When the length of a cube is increased n times, then every surface on that cube increased by n2, and its volume by n3.  
  48. Isometric scaling. Linear relations: Length vs. length
  49. Isometric scaling. Non-linear relations: Surface area, volume vs. length
  50. Allometry:  Metabolic rate versus body mass
    1. Kleiber's law

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