BIOL 322 FINAL PAPER 2026
CERTIFICATION EVALUATION QUESTIONS
AND SOLUTIONS GRADED A+
●● what property of fluids allows hydrostatic skeletons to work?.
Answer: fluids are incompressible, so force is transmitted across the
body
●● what is a muscular hydrostat? provide example.
Answer: a structure made entirely of muscle (no fluid cavity) that
functions like a hydrostatic skeleton. eg. octopus arm
●● give 3 materials that can function as hydrostatic skeletons.
Answer: -fluid (coelom)
-muscle (muscular hydrostat)
-parenchyma tissue (eg. flatworms)
●● what happens when circular or radial muscles contract?.
Answer: diameter decreases -> length increases (extension)
●● what happens when longitudinal muscles contract?.
Answer: length decreases ->diameter increases (shortening)
, ●● why are antagonistic muscle sets important?.
Answer: they allow controlled shape changes (extension vs shortening)
●● what transmits force in soft bodied animals without a rigid skeleton?.
Answer: incompressible material (fluid or tissue) at constant volume
●● why do hydrostatic skeletons exhibit mechanical advantage?.
Answer: because they are constant volume systems
●● what is the volume equation for a cylindrical hydrostat?.
Answer: V= πr^2L
●● what is the relationship between diameter and length in hydrostats?.
Answer: non linear (small decrease in diameter -> large increase in
length)
●● what happens to length when diameter decreases slightly?.
Answer: length increases dramatically (displacement amplification)
●● what is amplified in long thin hydrostats.
Answer: displacement (speed and reach)
CERTIFICATION EVALUATION QUESTIONS
AND SOLUTIONS GRADED A+
●● what property of fluids allows hydrostatic skeletons to work?.
Answer: fluids are incompressible, so force is transmitted across the
body
●● what is a muscular hydrostat? provide example.
Answer: a structure made entirely of muscle (no fluid cavity) that
functions like a hydrostatic skeleton. eg. octopus arm
●● give 3 materials that can function as hydrostatic skeletons.
Answer: -fluid (coelom)
-muscle (muscular hydrostat)
-parenchyma tissue (eg. flatworms)
●● what happens when circular or radial muscles contract?.
Answer: diameter decreases -> length increases (extension)
●● what happens when longitudinal muscles contract?.
Answer: length decreases ->diameter increases (shortening)
, ●● why are antagonistic muscle sets important?.
Answer: they allow controlled shape changes (extension vs shortening)
●● what transmits force in soft bodied animals without a rigid skeleton?.
Answer: incompressible material (fluid or tissue) at constant volume
●● why do hydrostatic skeletons exhibit mechanical advantage?.
Answer: because they are constant volume systems
●● what is the volume equation for a cylindrical hydrostat?.
Answer: V= πr^2L
●● what is the relationship between diameter and length in hydrostats?.
Answer: non linear (small decrease in diameter -> large increase in
length)
●● what happens to length when diameter decreases slightly?.
Answer: length increases dramatically (displacement amplification)
●● what is amplified in long thin hydrostats.
Answer: displacement (speed and reach)
