Metabolism in adverse conditions Flashcards
Adverse conditions
Extreme temperatures or lack fo water
What happens if organisms have normal metabolic rate in adverse conditions?
They will struggle and die since energy cost will be too great.
How do organisms survive these adverse conditions?
By changing the metabolic rate to not use too much energy when food is in short supply.
Dormancy -
When development of an organism is temporarily suspended, minimising metabolic activity and therefore saving energy until the environmental conditions improve.
Often a part is organisms lifecycle.
Two types of dormancy
Predictive dormancy and consequential dormancy
Predictive dormancy
When an organism enters the dormant phase before the onset of adverse conditions.
Consequential dormancy
When an organism will go into dormancy after the adverse conditions have arisen.
Predictive dormancy occurs in areas where conditions are…
Predicable and consistent
Consequential dormancy occurs in areas where conditions are….
Varied and unreliable
Example of predictive dormancy
Deciduous trees losing leaves so as to have a lower water loss
Example of dormancy
Hibernation
Hibernation:
Often done by mammals, response of animal to avoid adverse conditions such as low temperature of winter and reduction of metabolic rate - can be predictive of consequential. Normal functions of an organism change dramatically .
Hibernation process
Last many weeks/months
Often predictive - animal will consume extra for which is laid down as fat storage.
Metabolic rate drops which allows body temperature to lower to surrounding temperature.
Lower heartbeat and breathing mean less energy is expended, homeostatic mechanisms remain in place
Aestivation:
Form of dormancy
Allows survival in high temperature or drought.
Organism will bury itself in the ground where temperatures are cool, once there the organism will lower metabolic activity in a similar way as hibernation.
Daily torpor
Form of dormancy Short period (eg. part of a day) of reduced activity in organisms with high metabolic rates, it involves reduction in heart and breathing rate.
