Temperature
What is temperature?
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 with changing weather) or long term such as with the seasons or longer-term climate change. Temperature can also vary with location (exposed vs shaded, altitude, or latitude)
Air temperature, 2016 – 2017 — Vancouver
Source: Environment and Climate Change Canada
Average monthly seawater temperatures, 2016 — Vancouver
Why is temperature biologically important?
Temperature is an important abiotic factor because of its profound effects on the survival, growth, and reproduction of organisms. When an organism gains thermal/heat energy from its environment, the movement of atoms and molecules in its body increases, resulting in increased reactivity of molecules and increased rates of chemical reactions and biological processes (Moyes & Schulte 2006). Conversely, loss of heat energy to the environment results in decreased rates of chemical reactions and biological processes.
Metabolism refers to all of the chemical reactions needed to sustain life. Enzymes within cells catalyze these metabolic reactions, including converting food (sugars) into energy in the form of ATP. As the universal energy currency in living systems, ATP in turn fuels further biochemical reactions and ultimately, biological processes like finding food and avoiding predators. All enzymes function best at an optimal range of temperatures (Freeman et al. 2014). Therefore, variation in environmental temperature has wide-ranging implications on the physiology and ecology of organisms
Metabolism refers to all of the chemical reactions needed to sustain life. Enzymes within cells catalyze these metabolic reactions, including converting food (sugars) into energy in the form of ATP. As the universal energy currency in living systems, ATP in turn fuels further biochemical reactions and ultimately, biological processes like finding food and avoiding predators. All enzymes function best at an optimal range of temperatures (Freeman et al. 2014). Therefore, variation in environmental temperature has wide-ranging implications on the physiology and ecology of organisms
How do animals respond to variations in temperature?
Animals cope with changes in environmental temperatures in two major ways — tolerance and regulation (Moyes & Schulte 2006). Ectotherms (from ecto = outer and therm = heat), such as the invertebrates you are studying, are animals that must rely on heat from the surrounding environment to warm their bodies as their low metabolic rate does not generate enough heat (Freeman et al. 2014). Thus, the body temperature of ectotherms is primarily determined by environmental temperature. Endotherms (from endo = inner), such as birds and mammals, maintain an optimal body temperature using heat released through their high metabolic rate (Freeman et al. 2014). The body temperature of endotherms is, therefore, not primarily determined by environmental temperature.
In addition to the physiological strategies of ectothermy and endothermy, animals also display behavioral strategies for coping with environmental temperatures (Moyes & Schulte 2006). Animals alter their behaviour to modify their body temperature (behavioral thermoregulation). For example, some invertebrates can stay in the sun or on a hot rock to heat themselves, or burrow into the substratum to minimize heat loss during winter. To avoid excessive heat in summer, animals can find shelter (shade) from the heat source, immerse themselves in cool water, or burrow into a cooler substratum.
In addition to the physiological strategies of ectothermy and endothermy, animals also display behavioral strategies for coping with environmental temperatures (Moyes & Schulte 2006). Animals alter their behaviour to modify their body temperature (behavioral thermoregulation). For example, some invertebrates can stay in the sun or on a hot rock to heat themselves, or burrow into the substratum to minimize heat loss during winter. To avoid excessive heat in summer, animals can find shelter (shade) from the heat source, immerse themselves in cool water, or burrow into a cooler substratum.
Key search terms: · Temperature · Ectotherm · Metabolism · Enzymes · ATP · Thermoregulation
References Cited
Freeman S, Harrington M, Sharp J. 2014. Biological science. 2nd Canadian ed. Toronto: Pearson.
Moyes CD, Schulte PM. 2006. Principles of animal physiology. San Francisco: Pearson.
Note: Any edition of the above books or other biology textbook could be useful.
Freeman S, Harrington M, Sharp J. 2014. Biological science. 2nd Canadian ed. Toronto: Pearson.
Moyes CD, Schulte PM. 2006. Principles of animal physiology. San Francisco: Pearson.
Note: Any edition of the above books or other biology textbook could be useful.
To learn more:
Abram PK, Boivin G, Moiroux J, Brodeur J. 2017. Behavioural effects of temperature on ectothermic animals: unifying thermal physiology and behavioural plasticity. Biol. Rev. 92:1859–1876. doi: 10.1111/brv.12312.
Lagerspetz KYH, Vainio LA. 2006. Thermal behaviour of crustaceans. Biol. Rev. 81:237–258. doi:10.1017/S1464793105006998.
Schulte PM. 2015. Review. The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment. The Journal of Experimental Biology. 218:1856–1866. doi:10.1242/jeb.118851.
Abram PK, Boivin G, Moiroux J, Brodeur J. 2017. Behavioural effects of temperature on ectothermic animals: unifying thermal physiology and behavioural plasticity. Biol. Rev. 92:1859–1876. doi: 10.1111/brv.12312.
Lagerspetz KYH, Vainio LA. 2006. Thermal behaviour of crustaceans. Biol. Rev. 81:237–258. doi:10.1017/S1464793105006998.
Schulte PM. 2015. Review. The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment. The Journal of Experimental Biology. 218:1856–1866. doi:10.1242/jeb.118851.