Comparative Physiology Flashcards
What is comparative physiology?
Comparison of physiological attributes between and within levels of biological organisation to gain a better understanding about how individuals/populations function.
Why are plants important in comparative physiology?
- Oxygen
- Fuel
- Food
- Textiles
- Prescription and Non-prescription drugs
What are the research benefits to working with plants?
- Minimal ethical implications
- Easily accessible working materials
- Readily transformed to generate mutant lines
What are the different aspects of plant physiology?
- Phytochemistry
- Morphology
- Molecular and cellular biology
- Environmental interactions
- Cellular interactions
What is Phytochemistry?
The study of phytochemicals, which are chemicals derived from plants.
What is the concept “bottom-up”?
Looking at an organism in the order of:
Cells –> Tissues –> Organ –> Organ System –> Organism
What is the difference between plant cell wall and fungi cell wall?
Plant cell walls are made of cellulose, hemicellulose and pectin. Fungi cell walls are made of chitin.
What are characteristics of a plant cell wall?
It provides shape, rigidity, support and aids intercellular communication. Prevents excessive uptake of water. The plant cell in hypotonic solution can hold excess water and remains intact. However, animal cell in hypotonic solution swells and bursts.
What is Hypotonic solution?
Hypotonic solution is one in which the concentration of solutes is greater inside the cell than outside of it
What is a Hypertonic solution?
Hypertonic solution is one where the concertation` of solutes is greater outside the cell than inside it.
What are modifications to the plant cell wall which change the tissue?
The plant cell wall is embedded with:
- Lignin to provide support
- Suberin which is watertight
- Cutin which forms a waxy cuticle
What are a few features of the plant organs e.g. the vascular system?
The Xylem distributes water and dissolves minerals upwards through the plant.
Lignin stiffened to provide support.
Phloem carried food downward from the leaves to the roots.
What is the concept “top-down”?
Looking at an organism in the order:
Organism –> Organ System –> Organ –> Tissues –> Cells
What Tissues make up the stomach?
- Epithelial Tissue
- Connective Tissue
- Muscle Tissues
- Nervous Tissue
What is the function of Epithelial Tissue?
Form active interfaces with the environment and external nd internal surface.
What is the function of Connective Tissue?
Binds and supports other tissues.
What is the function of Muscle Tissues?
Contracts moving parts of the body.
What is the function of Nervous Tissue?
Transmits nerve impulses.
What is the function of Surface mucous cells?
Produce mucus to lubricate and protect.
What is the function of Parietal cells?
Secrete HCI.
What is the function of Chief cells?
Secrete digestive enzyme precursor.
The size of an animal affects which aspects?
Size affects all aspects of an animals:
- Physiology
- Behavior
- Ecology
What is the definition of scaling?
Structural and functional consequences of changes in size or scale among otherwise similar organisms.
Why do we use/publish scaling relationships?
We use published scaling relationships to get estimates. These can be used for difficult or impossible measurements (e.g. extinct animal weight).
Why should we expect organisms to be affected by size?
Due to geometry and physics.
How does surface area change as length squared and volume increase?
Surface area increases as length squared and volume increases.
How does the squared and cubed laws hold in regard to how we measure lengths?
The squared and cubed laws hold regardless of how we measure lengths. As we make the animal bigger in size, its volume increases faster than its surface area.
Why is surface area and volume important for animals?
Some physiological processes will be dependent on surface area (e.g. wingspan), others dependent on volume (e.g. pond skater volume for travelling over water surface).
What are processes related to surface area?
Things that are about interfacing the animal with its environment scale with surface area. Examples:
- Heat Loss (from outer surface of organism)
- Absorption of food (surface area of the gut wall)
- Absorption of oxygen (related to area of lung tissue presented to the air)
What are quantities related to volume?
Things intrinsic to the animal itself might generally be linked to volume. For example:
- Mass
- Energy Stores
- Volume of blood
How do we measure size?
Usually we use mass as it is easy to measure and is independent of body plan.
What is the formula for scaling relationships?
Y = aMᵇ
Y: the thing you are interested in
a: the proportionality constant
M: mass
ᵇ: the mass exponent
In the formula “Y = aMᵇ”, what does the value of ᵇ tell you?
If ᵇ is positive then Y increases with increasing mass.
If ᵇ is negative then Y decreases with decreasing mass.
The larger the magnitude of ᵇ, the more dramatic the change in the property of interest with increasing size.
What is the value of ᵇ when comparing maximum energy output and resting power production?
ᵇ is larger for maximum energy output than for resting power production.
What is the Aerobic scope?
The aerobic scope of an animal is the maximum power output divided by the minimum power output.
Aerobic Scope = Rmax / R
What does the algebra tell us about the scaling of aerobic scope?
Our prediction would be that an animal more than five times the mass than another would only have a very slightly bigger aerobic scope. This is confirmed by empirical evidence.
What is Isometric scaling (Jargon)?
Scaling with ᵇ values equal to 1.
What is Allometric scaling (Jargon)?
Any scaling relation where ᵇ is not equal to 1 (e.g. 0.75 or -0.09).
Why do bigger animals have proportionately thicker bones?
Vertebrates stand supporting their weight with their legs. Leg bones have a breaking strain measured in Nm-2. Force of gravity increases with mass. Strain of isometric bones would increase with size.
What is mass-specific resting metabolic rate?
Mass-specific resting metabolic rate is the resting metabolic rate of an animal divided by its mass. Used to compare things controlling for size.
How is “Y = aMᵇ” calculated?
Simple linear regression
Logging both sides
log(Y) = log(a) + ᵇlog(M)
so plot log(Y) against log(M)
log(a) is the y-intercept and ᵇ is the gradient
