Energy budgets Flashcards
What are the energy demands of organisms
maintenance, growth, activity, reproduction
energy budget depends on..
size, activity, environment
What is scaling?
The study of the effect of size/mass on anatomy/physiology
All shape SA is proportional to?
length squared
what is the Surface area of organisms
membrane/skin
what makes up the volume of organisms
mass, cytosol, nucleus
Large organism have a _____ SA/V ratio than small organisms
smaller
Large organisms need to maintain large internal SA to….
exchange matter and energy with environment
Small SA/V ratio are ____ to large organisms because they need ____…
disadvantage, nutrient exchange and NRG generation
Small SA/V ratio are _____ to small organisms because they can use _____
advantage,
heat retention (heat is produced by entire volume and lost through surface area)
Allometry is a _____
type of scaling where aspects of biology do not vary proportionally to the size of the organism (characteristic of organism changes with size)
b=1 means
isometric (both domains are proportional to each other)
b=0 means
aspect of biology is independent of mass
b= any other value
it is allometric (characteristics of organism changes with size)
_____ have a larger O2 consumption relative to_______
smaller animals , larger organisms
Higher mass: _____ msMR, _____ absolute MR
lower
higher
When the graph is linear, ______ becomes the ____ of the line.
B (scaling exponent)
slope
isometry is when
both domains remain proportional, slope is 1
ex. The mass of the heart increases (almost)
isometrically with the mass of the organism
isometric when b= ___ to ____
b= 0.98 – 1.02
Positive Allometry is also called
hyperallometry
Positive Allometry (hyperallometry) is when
As one dimension increases, the other increases to greater proportion (slope greater than 1)
Negative Allometry is also called
(hypoallometry)
Negative allometry (hypoallometry) is when
as one dimension increase, the other increase to a lesser proportion (slope less one)
energy budget equations
energy in (from food) = energy out
Energy IN = Energy ASSIMILATION + Energy EXCRETION
Energy ASSIMILATION = Energy RMR + Energy ACTIVITY + EnergyPRODUCTION
Energy IN = Energy RMR + Energy ACTIVITY + EnergyPRODUCTION + Energy EXCRETION (this is NRG available to organism)
Large organisms need more food than small organisms, meaning they ______
have a greater Ein value per unit time
Large organisms can also eat more food at a given time than small organisms, meaning they _______
eat less often than small organisms relative to the body size
Large organisms take in more air with each breath; pump a greater volume of blood with each heartbeat, meaning they
have a lower breathing and heart rate than small organisms
What is a measure of evolutionary fitness?
the Total amount and rate at which organisms obtain NRG from food
How long food remains in digestive tract is a ____
phenotypic trait that responds to selective pressures in environment (pressures: how long digestive tract is, if you eat plants, it takes more time to digest)
longer it takes to digest food, longer the _______
retention time
Energy excretions
step 1: Food needs to be ________ this takes up energy and represents ______ – harder to _____ takes more NRG
broken down (chewing, enzymes, etc)
energy
a net loss of energy
digest
Step 2: Nutrients are _______, leads to a net _____
absorbed through digestion
gain of energy
step 3: Eventually, all __________, leaving ______ for excretion
possible energy is extracted
undigestible “dregs”
Metabolic rate is the ___
Rate of energy consumption (rate at which it converts chemical NRG to heat and external work)
Benefits of measuring metabolic rate:
- helps determine how much food animal needs
- quantitative measurement of total activity of all physiological mechanisms
- helps to determine the pressure on energy supplies in the ecosystem
Resting metabolic rate
NRG expenditure at rest but routine activities/day
Basal metabolic rate (BMR)
metabolism at complete rest (lowest possible),
applies to homeotherms (endotherms), when it’s in the thermal neutral zone, fasting or resting
Standard metabolic rate (SMR)
metabolic rate measured at a specific body temp. Applies to Poikilotherm (ectotherms), measured when its fasting or resting
Ways to measure metabolic rate
Direct calorimetry
indirect calorimetry
- respirometry
- material balance method
Direct calorimetry is
the measure of heat loss, measures the rate at which heat leaves an animals body, expensive and cumbersome
indirect calorimetry is
the measure of O2 consumed or CO2 produced, cheaper and easier
respirometry is
measuring animals rate of respiratory gas exchange with its environment
material-balance method is
measuring chemical energy content of the organic matter that enters and leaves the animals body
Smaller animals have a _________ demand due to high _____
higher energy
SA/V ratio
what is Energy activity
most forms of movement above resting state
heat generated from increased activity may cover
the thermoregulation costs of a dormant (resting) organism
Energy production:
Represents both growth and reproduction
If organism has balanced NRG budget:
Eproduction value will be zero (in adults)
If more than enough NRG is consumed:
Eproduction value is positive and mass increases
If not enough NRG is consumed:
Eproduction value is negative and mass decreases
(because they lose mass to cover the energy deficit)
PRACTICE CALCULATIONS
NOW!!!!
