lec 8 lab 7 - metabolic rate Flashcards
define direct calorimetry
Direct calorimetry is a method used to measure an animal’s metabolic rate by directly measuring the heat it produces.
In direct calorimetry, the animal is placed inside a special chamber where the heat it releases is measured. By measuring how much heat the animal gives off over a certain period of time, scientists can calculate its metabolic rate, which tells us how fast its body is burning energy.
define indirect calorimetry (respirometry)
measures rate of respiratory gas exchange of an animal, by analyzing the amount of oxygen an animal consumes and the amount of carbon dioxide it produces, scientists can calculate how much energy it’s using, which gives them an idea of the animal’s metabolic rate.
Closed configuration respirometry
putting an organism in a sealed box to see how it breathes. The box measures the changes in air inside caused by the organism’s metabolism. By watching how the air changes, scientists can figure out how much oxygen the organism uses and how much carbon dioxide it produces, helping them understand how active or energetic it is.
open flow respirometry
animals are placed in a sealed chamber or a respirometer where the exchange of gases with the surrounding environment is continuously monitored. As the animal breathes in oxygen and exhales carbon dioxide, the concentrations of these gases in the chamber change over time. By measuring the rate of change in gas concentrations, scientists can calculate the animal’s oxygen consumption (VO2) and carbon dioxide production (VCO2), which are used to determine its metabolic rate
Intermittent flow respirometry
where a sealed chamber periodically flushes with fresh air or a known gas mixture. Changes in gas concentrations within the chamber between flushes are used to calculate the animal’s metabolic rate, making it particularly useful for studying small organisms or those with low metabolic rates.
What is q10? (definition AND formula)
Q10 - temperature quotient - how much rate changes for every 10 degree celsius in temp change. For eg. if Q10 = 2, then metabolic rate doubles every 10 degrees
q10 = (k2/k1)^10/(t2-t1)
k = metabolic rates, t = temperatures
Why are small fish poikilotherms (vs large marine animals)
Small fishes need to be poikilothermic because water’s high heat capacity and conductivity make it challenging to regulate body temperature, and they need to constantly pass water over their gills for oxygen. Unlike many terrestrial ectotherms, small fishes struggle to regulate temperature behaviorally due to these factors.
In contrast, most marine mammals are large, which gives them higher thermal inertia and a lower surface area to volume ratio, making it easier for them to regulate temperature in cooler water.
