14.4: Physical Factors - Temperature
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Temperature
Temperature governs the rate chemical and metabolic rates especially in cold-blooded organisms.
Many organisms are sensitive to changes in temperature and this results in species zonation.
Example—Different species of sharks: Sharks can be classified as tropical, temperate, or polar, depending on the surface temperature of the ocean region they inhabit.
Tropical sharks live year round in warm temperature waters (21° - 30° C, 69.8° - 86° F). Examples include nurse shark, the tiger shark, and the bull shark. They are only comfortable in warm waters where food is plentiful, so they remain there year-round without migrating. |
Sharks in Temperate regions tolerate temperatures within a range (10°-21°C, 50-69.8° F). Sharks in temperate regions tend to migrate south in the winter and north in the summer and as their food sources move up and down the coast. |
Sharks in Polar regions always stay in colder waters (below 5° C, 41° F). For example, Greenland sleeper shark is adapted to living under ice floes and will not migrate. |


Temperature controls an organism's metabolism |
For poikilothermic (or cold blooded) organisms: every 10° C rise in temperature doubles their metabolism. Most fish, reptiles, and invertebrates are cold blooded. |
For homeothermic (or warm blooded) organisms: metabolism increases with decreasing temperature to stay warm. Only mammals and birds are warm blooded. |
Some species have various degrees of thermo regulation - ability to raise or lower their body temperature. An example in fish is Opah an Blue Fin Tuna. |
