Lecture 26- Functional design of organisms I Flashcards
What is movement of water important for? (4)
- Movement and mixing of gametes 2. Recruitment of planktonic larvae 3. Delivery of nutrients to macroalgae 4. Mechanical stresses from currents/waves
How is water movement important for mixing of gametes?
via diffusion and advection diffusion and advection are the two main ways gametes move -the gametes spread via diffusion -advection=is the velocity over time -adults need to coordinate to release at the same time -use chemical cues
What is advection?
- transport mechanism of a substance or conserved property by a fluid due to the fluid’s bulk motion
What is diffusion?
-the net movement of a substance (e.g., an atom, ion or molecule) from a region of high concentration to a region of low concentration
How is water movement important for the recruitment of planktonic larvae?
-larval period of many organisms -float around hours, months up to a year -moved around by diffusion and advection as well -at small scale these processes are important -motion is important for transport and dispersal
How is movement of water important for delivery of nutrients to macroalgae?
water mivement will deliver nutrients to algae attached to bottom -some of the nutrients are from land -need water movememnt otherwise there will be depletion of nutrients in the immediate vicinity of the leaves -so there are areas where really low nutrients around the leaves if water not moving
Where do the nutrients in the sea come from?
- Land 2. Upwelling 3. Waste of other organisms in the sea (nitrogen can come from this source)
What is the nutrient that is mostly the one in shortage in the sea?
-Nitrogen -in some parts Iron as well (centres of oceanic basins)
Why is it hard for macroalage to get the total reactive nitrogen that enters the sea?
-gets sucked up very quickly by the phytoplankton -not much left to sink to the bottom -macroalgae get most of their nitrogen from animal waste
What is viscosity?
- a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the informal notion of “thickness”. For example, honey has a much higher viscosity than water. -due to the friction between neighboring particles in a fluid that are moving at different velocities.
What is dynamic viscosity?
-An ideal pair of thin, flat plates. If the lower plate is fixed, it takes a force to keep the upper one moving. The magnitude of that force is proportional to the dynamic viscosity of the fluid between them. The length of each horizontal arrow between the plates is proportional to the local flow speed.! -the plates move depending on to which plate the fluid is closer to -how much force you have to apply to the top plate depends on the viscosity of the fluid,
What is the equation for the local shear velocity?
- funny t= measure of shear force, force per surface unit
- the u is the dynamic velocity
What symbol has the kinematic velocity?
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What is kinematic viscosity?
•The practical gooiness of a fluid • How easily it flows •How likely it will break out into numerous vortices • How steep are the velocity gradients
What is the equation for the kinematic viscosity?
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