Maintaining Metabolism

Question 1

Dormancy

Answer 1

Dormancy is part of the lifecycle of some organisms to allow survival during a period when the costs of continued normal metabolic activity would be too high. The metabolic rate can be reduced during dormancy to save energy. During dormancy, there is also a decrease in heart rate, breathing rate and body temperature.

Question 2

What are the two types of dormancy?

Answer 2

predictive or consequential

Question 3

Pros of predictive dormancy?

Answer 3

A predictive strategy allows dormancy to occur before the onset of unfavourable conditions. For example, decreasing temperature and day lengths are cues in seasonal environments that predict the onset of winter.

Question 4

Pros and cons of consequential dormancy?

Answer 4

A consequential strategy enables the organism to react immediately to environmental cues. Organisms only enter a state of dormancy after they have been exposed to the adverse conditions. This is typically found in unpredictable environments where conditions may change very quickly. There is an enormous disadvantage to this, as a sudden change in conditions may result in high mortality rates. However, the organisms can delay dormancy until adverse conditions arise, meaning that they can make full use of the resources available in the habitat for as long as possible.

Question 5

Daily torpor

Answer 5

Daily torpor involves the reduction of an organism’s activity and metabolic rate for part of the day. Daily torpor often involves a reduction in heart rate and breathing rate. This allows organisms with high metabolic rates to save energy when they would not be able to find food. For example, house mice are active during the night and experience torpor through the day when it would be dangerous for them to be out in the open foraging for food.

Question 6

Hibernation

Answer 6

Hibernation is used by many organisms to escape cold weather conditions and scarce food supplies. The normal body functions of an organism change dramatically during hibernation. For example, the heart rate of the jumping mouse falls from 600 beats per minute to just 30 beats per minute. Animals prepare for hibernation by eating lots of food in the late summer and autumn. This builds up a layer of fat which keeps them warm and acts as a food source during the hibernation period. Hibernation can be either a predictive or consequential strategy. This form of dormancy is commonly seen in mammals such as hedgehogs, bears and dormice.

Question 7

Aestivation

Answer 7

Aestivation is a form of dormancy entered into by organisms in response to very hot and dry conditions. For example, the garden snail and some worms become dormant until moisture levels rise again. The snail retreats into its shell and seals the end and the worm coils up in a pocket of air surrounded by mucus. A more amazing example of aestivation is the lungfish, found in South America and Africa. This fish survives drought by burying itself in the mud on the river bed; the mud dries with the fish inside where it is able to survive until the next rainy season. Aestivation is a consequential strategy.

Question 8

Explain migration with energy?

Answer 8

All migration involves a considerable investment of energy from the individuals concerned, but is beneficial in the long-term, as it allows them to relocate to a more suitable environment.

Question 9

Migration behaviour

Answer 9

Migratory behaviour is thought to be influenced by both innate and learned behaviour.

Question 10

How to track migration?

Answer 10

Techniques have been developed to study long distance migration. These include tagging, radio tracking, capture and release, and direct observation.