Metabolism and adverse conditions

 

Introduction

Dormancy

Migration

Extremophiles


 

Introduction

 

Maintaining an active metabolic rate may not be possible at all times. Adverse conditions mean that energy would be wasted on surviving in situations that don’t allow for reasonable living activities for a period of time. Therefore, metabolic rate must decrease to allow for this.

 

Dormancy

 

Dormancy occurs in organisms sporadically or as part of their lifecycle, and can be used as a response to cold, heat, lack of food or other environmental stresses that prevent the upkeep of an active metabolic state.

 

When dormancy takes place proactively and the period of e.g. cold is anticipated, dormancy is predictive. Predictive dormancy takes place in some plants. When it’s done retroactively once the stressor has begun, it’s consequential.

 

Predictive dormancy is a good idea because it avoids the damage of the environmental stressor, and a bad idea because it might be too preemptive and miss out on resources if the prediction is off. Hence, consequential dormancy is advantageous as it enables organisms to make the most of present resources and only decrease their metabolic rate if really necessary. A clear risk with this strategy is the sudden onset of detrimental abiotic factors that can damage organisms before they can mount a response.

 

One type of dormancy in animals, notably mammals, is hibernation. This is a state of lowered metabolism that takes place in cold conditions when food becomes scarce. Animals must prepare for hibernation by storing up extra energy, as a thick layer of fat tissue. Hibernation occurs as metabolism decreases along with body temperature and heart rate, and can go on for days or months, depending on the species and environment….

 

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