Comparative Anatomy and Physiology of Animals
Lecture 23 Aquatic locomotion 19/01/21
Aquatic animals
- Animals that walk or crawl on the sea floor have similar locomotion mechanics to terrestrial
animals.
Important forces
- Buoyancy.
- Gravity.
- Drag.
Moving through water
- All aquatic animals must swim.
- Achieved through different ways
- These are also called gaits.
- Definition of gaits: pattern of locomotion characteristic of a limited range of speeds,
described by quantities of which one or more changes discontinuously at transitions to other
gaits.
- Positive buoyancy reduces effect of gravity.
- High density of water increases effect of drag.
- Eater must be pushed back to achieve forward thrust (wake).
Reynold’s number
- Re = ρ V L /µ
- ρ = density.
- V= velocity.
- L = length.
- µ = viscosity.
Lecture 23 Aquatic locomotion 19/01/21
Aquatic animals
- Animals that walk or crawl on the sea floor have similar locomotion mechanics to terrestrial
animals.
Important forces
- Buoyancy.
- Gravity.
- Drag.
Moving through water
- All aquatic animals must swim.
- Achieved through different ways
- These are also called gaits.
- Definition of gaits: pattern of locomotion characteristic of a limited range of speeds,
described by quantities of which one or more changes discontinuously at transitions to other
gaits.
- Positive buoyancy reduces effect of gravity.
- High density of water increases effect of drag.
- Eater must be pushed back to achieve forward thrust (wake).
Reynold’s number
- Re = ρ V L /µ
- ρ = density.
- V= velocity.
- L = length.
- µ = viscosity.
