Flashcards in Body Size and Scaling Deck (18)
What are the main physiological functions?
Metabolism, Homeostasis, Reproduction and Growth
How does physics affect physiology?
Larger animals experience a greater gravitational force
What happens to surface area with increasing size?
Larger animals have a smaller SA:V ratio, as volume increases more rapidly that SA
Why does size matter in physiology?
Larger animals tend to move slower, have slower digestion rates, slower respiration rates and lose heat and water to the environment less quickly
What is allometry?
The study of differential growth and how physiological processes scale with body size
What is ontogenetic allometry?
During the growth of a single organism, looking at the developement of an individual organisms anatomy from earliest stage to maturity
What is static allometry?
Between different individuals at the same developmental stage within a species
What is isometric scaling?
Where everything grows in proportion, growth is approx at the same rate, and adult proportions are not significantly different from those of the juvenile
What is evolutionary allometry?
Between individuals of different species
What is the equation used for describing allometric relationships?
(size of the body part = an initial growth rate x measure of whole body ^ scaling exponent )
What does it mean if b= 1
Isometry- variable scales at same are as whole body size
What does it mean if b= 0
No Relationship - Size of variable unrelated to whole body size
What does it mean if b < 1
Negative allometry - Variable increases slowly relative to whole body size
What does it mean in b > 1
Positive allometry - Variable increases at faster rate than whole body size
What do log-log scales do?
Linearise the relationship
How is the square cube law applied in isometry, and why does this present a problem?
Isometric doubling of length will increase surface area fourfold and volume (thus mass) eightfold. Organism has 8x mass to support but area to support weight increases 4x. Organism has 8x metabolically active tissue to support, but respiratory surface areas only increase 4x
How do you work out metabolic rate?
Metabolic rate (MR) = Body weight (W) 0.75