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Biomechanics and Biophysics
Physics and Math
Body size and constraints
Gravity is important to big animals
Smaller animals are not affected as much by gravity; are affected though by surface
forces or tension (example: ant in the rain)
Size
???? Can an elephant run????
Never run
impact on limbs is too great
We define running as a form of locomotion as all limbs must leave the ground at
sometime
Absolute vs Relative
Absolute
size increase is equal to the direct increase in length, volume/mass, and
surface area (example: head
as adult gets larger)
Relative
size increases is equal to the differential increase in length, volume/mass, and
surface area (example: head
as adultsmaller)
Surface area and Volume
SA: L^2
V: L^3
Volume increases faster than surface area
???? Is the blue whale the largest organism to inhabit the earth ever????
No, fungus
Armillaria ostoyae
(honey mushroom)
•
2200 acres
•
3.5 miles in diameter
•
24007200 years old
•
Located in Oregon
Surface Area
SA=4*h*r^2
Problem:
Blue whale=2438 cm long=1.86e7 cm^2
Shrew=8cm long=201 cm^2
V=4/3*h*r^3
Whale=7.59e9 cm^3
Shrew=268 cm^3
•
300 time increase in size (smallest to largest)
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93000 folds increase in surface area
•
28 millionfold increase in volume
•
SA: V=1:300
Metabolism=VO
2
•
Y=bx^a (Allometric scaling)
o
Allometry is the proportion of things
o
“b” and “a” are constants
o
Forms a parabola
Log y=Log b+ Log x^a
Log y=Log b + a Log x (forms a straight line)
o
Absolute (see graphs)
o
For every increase in mass, there is a small increase in metabolism
o
Slope of line=0.738
o
Relative (see graphs)
o
Amount of Oxygen consumed per hour per given gram of animal
o
As we increase in size, you increase in efficiency, such that each gram of
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This note was uploaded on 06/01/2011 for the course BIOL 3350 taught by Professor Staff during the Spring '08 term at Kennesaw.
 Spring '08
 STAFF
 Anatomy, Biophysics, Biomechanics

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