Animal Ecophys Flashcards
What is the specific dynamic action ?
Energy cost of digesting food
What is BMR ?
Rate of energy expended by a resting animal that is post absorptive and in a thermonuclear range.
What is RMR ?
Rate of energy expended by a resting animal of unknown absorptive rate.
What is SMR ?
Rate of energy expended by a resting animal at any given temp
What is FMR ?
Rate of energy expended by an animal at any given time
What are 2 techniques for measuring metabolism ?
Direct calorimetry
Indirect calorimetry
What does direct calorimetry measure ?
Total heat production
What 2 techniques are used in indirect calorimetry ?
Measurement from food intake & waste excretion
Respirometry- Measures amount of O2 used in oxidative process
What is the problem with measuring CO2 as a measure for MR ?
If energy store being utilised by the animal is different from prediction then CO2 has a massive error rate.
Give a brief description of TEB ?
Continuously record the behaviour of the animal
Measure how long the animal spent performing each behaviour
Assign energy values to each behaviour
Calculate the overall energy expenditure
What are the benefits and negatives of TEB ?
Benefits:
Technically easy
No technical equipment needed
Negatives:
MR of individual behaviours has to be known
Difficult to use accurately as other factors will affect the MR
Need to conform to standard operative temperature
Labour intensive
Give a brief description of DLW technique.
- Catch your animal
- Inject it with water that has been labelled with 18O (H218O) and Deuterium (2H2O)
- Allow the injectate to equilibrate with the body water pool
- Take a sample of body water e.g. blood
- Release the animal
- Recapture after a specified interval
- Take a final body water sample
- Analyse water samples using a mass spectrometer
With regards to DLW technique how is CO2 production calculated ?
The difference between rate of loss of 18o and 2H because 18o is lost as H218o and c18o2 wheres as 2H is lost as 2H2o
What are the drawbacks of DLW ?
- Only estimates the mean energy expenditure over the measuring period
- Not feasible to measure over short time resolution
- May have reduced precision in very active animals
- Can be problems trying to convert CO2 production to estimates of energy expenditure
What assumptions does the DLW technique use ?
- Body water remains constant
- Rates of water and CO2 flux remain constant
- Isotope labels only the body water (i.e they are not incorporated in tissues)
- Isotopes are lost only as CO2 and/or H2O
- Labelled or unlabelled CO2 and/or water does not enter the animal via respiratory or skin surfaces
Describe the heart rate technique procedure.
- Make calibrations
2.Oxygen consumption and fH recorded over time
Estimates of VO2 from fH compared with those measured via respirometry
3.fH monitor attached or implanted
4.fH recorded over time from free-living animals
5.VO2 estimated from fH recorded in the field using the calibrations
What are the benefits of HR technique ?
- Long periods of monitoring - potential for circa-annual estimates of MR
- Short time resolution
- Easy to integrate with behavioural data
- Can be used to estimate the MR of specific activities/behaviours
- Accurate estimates
- A physiological measure
What are the Drawbacks of HR technique ?
- Has to be calibrated with respirometry
- Calibration is species-specific
- Different muscle groups may have different relationships e.g. birds
- All the parameters have to vary systematically
- Measures only aerobic metabolism
- Technically very difficult to record in the field
Why might accelerometry result in an over estimate for energy expenditure ?
on moving water (may move device even though animal is still)
soaring on air currents
during periods of estivation/hibernation.
Why might accelerometry result in an under estimate for energy expenditure ?
post-absorptive
outside of its thermal neutral zone
growing rapidly
gestating or carrying an infant
What is phenotypic plasticity ?
Environment can directly induce changes in an individuals behaviours, morphology and physiology
Organs changing in migration is an example
What 5 parameters define migration ?
Persistent prolonged movement
Straightened course of movement
Undistracted by usual stimuli (e.g. food, mates)
Distinct departure and arrival behaviour
Reallocation of energy in advance of migration
What 4 adaptations do birds have that allows flight ?
- reduced numbers of bone sand pneumatisation (strong & light)
- provision of a keel on the sternum for attachment of the flight muscles
- Magnetoreception
- Highly developed cerebellum
What muscles do the bird use for the upstroke ?
supracoracoideus
Why are birds different to mammals in terms of fat metabolism ?
Birds use fat stores (Triacylgycerol) for high intensity activity such as flying instead of carbs
What physiological changes do birds like the ruff make before flight and during in stop over ?
Fat stores increase and so does pectoral mass
Liver stays in same ratio as pectoral mass
Why does pectoral muscle decrease in flight ?
Some energy needs to be derived from protein thus the muscle is metabolised
What physiological changes do birds like the bar tailed godwit make before flight and during in stop over ?
Fat stores increase and so does pectoral mass
Liver increases during stop over then decreases before they leave for flight. This is a proxy for the digestive tract. This reduces weight
When do some birds use protein as the main fuel for migration ?
Depends what food sources are at stop over points/ breeding grounds
Golden plover uses protein for spring migration.
What energy saving mechanisms do birds exhibit during flying ?
V flight formation
Bird at front has highest flap frequency and highest heart rate subsequently birds behind have lower flapping frequency and HR thus save energy