The thermal environment
Temperature is a measure of the intensity of heat. Heat is the amount of energy associated with the movement of atoms and molecules in a body of matter.
How does temperature vary?
Temperature can vary with time over a short-term (daily or changing weather) or long term such as with the seasons or longer term climate change.
Why is temperature biologically important?
Temperature is an important abiotic factor because of its effect on the rates of biophysical processes such as diffusion and osmosis, and chemical reactions including metabolism.
Metabolism refers to all of the chemical reactions needed to sustain life. Enzymes within cells execute these metabolic reactions, including converting food (sugars) into ATP (which fuel further reactions). All enzymes function at an optimal range of temperatures.
Animals cope with environmental temperatures in two major ways. Ectotherms such as invertebrates must rely on heat in the surrounding environment to regulate their body temperatures. Endotherms such as birds and mammals maintain an optimal body temperature using heat released from their internal bodily functions.
Metabolism refers to all of the chemical reactions needed to sustain life. Enzymes within cells execute these metabolic reactions, including converting food (sugars) into ATP (which fuel further reactions). All enzymes function at an optimal range of temperatures.
Animals cope with environmental temperatures in two major ways. Ectotherms such as invertebrates must rely on heat in the surrounding environment to regulate their body temperatures. Endotherms such as birds and mammals maintain an optimal body temperature using heat released from their internal bodily functions.
How do animals respond to variations in temperature?
Ectotherms alter their behaviour to modify their body temperature (heat themselves or minimize heat loss). Some examples of how ectotherms can alter their behaviour to thermoregulate (heat themselves or minimize heat loss) include lying in the sun, climbing to higher ground (up trees, ridges or rocks), entering a warm water or air current, building an insulated nest or burrow, or lying on a hot rock.
Only endotherms are able to maintain a stable optimum temperature in at least a portion of their bodies by physiological as well as behavioural means.
Only endotherms are able to maintain a stable optimum temperature in at least a portion of their bodies by physiological as well as behavioural means.
To learn more:
Freeman S, Harrington M, Sharp J. 2014. Biological science. 2nd Canadian ed. Toronto: Pearson.
Smith TM, Smith RL, Waters I. 2014. Elements of ecology. Canadian ed. Toronto: Pearson.
Note: Any edition of the above books or other biology and/or ecology textbooks could be useful.
Freeman S, Harrington M, Sharp J. 2014. Biological science. 2nd Canadian ed. Toronto: Pearson.
Smith TM, Smith RL, Waters I. 2014. Elements of ecology. Canadian ed. Toronto: Pearson.
Note: Any edition of the above books or other biology and/or ecology textbooks could be useful.