1. Key Area 5 : Metabolism in Adverse Conditions
Unit 2: Metabolism and Survival

2. Environmental Conditions
Abiotic factors fluctuate in many environments.
They can vary beyond the tolerable limits required for the normal metabolic activity of an organism.
Extreme heat, cold, lack of food in winter and lack of water are conditions which organisms may not be able to withstand.
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3. Environmental Conditions
Write down as many ways that you can think of that animals use to avoid adverse conditions. What do they do to avoid these conditions?
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4. Surviving Adverse Conditions
Animals have become adapted to living in their particular ecosystems through natural selection and evolution.
They can possess adaptations which help them survive unpredictable environmental changes and fluctuations.
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5. Surviving Adverse Conditions
Adaptations to surviving adverse conditions can be either:
Structural
Physiological
Behavioural
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6. Surviving Adverse Conditions
Write a case study on the structural, physiological and behavioural adaptations that some animals in cold climates employ to survive these adverse conditions. Use the text book and websites in your note to help you.
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7. Surviving Adverse Conditions
An organism that lives in an environment where it experiences extremes of conditions, may have to expend large quantities of energy.
This energy will be used to maintain homeostasis.
This is not a good use of resources.
To counteract this, organisms can reduce their metabolic rate.
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8. Dormancy
Organisms can reduce their metabolic rate by undergoing a period of dormancy.
They can then survive periods of environmental adversity (temperature extremes, food scarcity).
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9. Predictive Dormancy
When an organism becomes dormant in advance of worsening conditions.
Usually genetically programmed.
Found in seasonal environments that are predictable.
Temperature/photoperiod used as environmental cues.
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10. Consequential Dormancy
When an organism becomes dormant after the arrival of adverse conditions.
Advantage: organism can remain active for longer utilising resources available.
Disadvantage: organism may be killed off before they can become dormant as conditions worsen.
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11. Examples of Dormancy Hibernation. Aestivation. Torpor.
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12. Hibernation
‘winter sleep’ enables mammals to survive adverse winter conditions.
It can last weeks or months.
It is often predictive and occur in response to a shortening day length.
Extra food is usually consumed in order to lay down a store of fat for the hibernation.
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13. Hibernation
The metabolic rate of the animal drops allowing the body temperature to drop to the surrounding environmental temperature.
A drop in heart rate is experienced along with a slower breathing rate.
Minimal energy is expended during this time; only enough to maintain the vital activities of the cells is spent.
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14. Hibernation Period of long term inactivity e.g. Hazel dormouse
e.g. painted turtles
e.g. marmots
e.g. peacock butterfly
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15. Aestivation ‘summer sleep’
Is similar physiologically to hibernation but occurs in summer.
Occurs in response to drought or extreme high temperatures.
e.g. lungfish,
garden snails,
giant bullfrog
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16. Aestivation
Desert amphibians - Spadefoot toads rise like zombies at the first rain.
Nile crocodiles go in to suspended animation to wait out drought
Jersey tiger moths and snails enjoy a restful summer
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17. Daily torpor
The physiological state where an animal reduces its normal metabolism and activity for part of every 24 hour cycle.
Reduction in metabolism is accompanied by a slowing down of the heart and breathing rate and a decrease in body temperature.
This is common amongst small birds and animals that have a very high rate of metabolism.
e.g. humming birds, bats and shrews.
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18. Daily torpor
These animals have a high surface area through which heat is lost.
This means that energy is lost and wasted.
These animals are active endotherms and need a high rate of metabolism to maintain their body temperature.
A daily period of torpor decreases the rate of energy consumption during a time where the animal would be unsuccessful in its food search and could be exposed to danger.
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19. Dormancy definitions Hibernation: period of long term inactivity.
Aestivation: dormancy in response to hot, dry conditions.
Daily torpor: period of short term inactivity in animals.
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20. Avoiding Adverse Conditions Migration
This is the regular movement by members of a species from one place to another over a relatively long distance.
It avoids metabolic adversity such as shortage of food, low temperature.
This gives the organism an advantage.
There is an initial expenditure of energy use in the relocation which is a disadvantage in the short term.
It is beneficial however in the long term.
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21. Migration Animals that migrate are:
Artic skuas, swallows, whales and butterflies.
Artic Tern migration:
This is an impressive journey as these birds fly almost Pole to Pole, covering 10,000 miles each way.
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22. Migration CfE Higher Biology Metabolism and Survival

23. Migration Humpback whale migration:
Have a wide geographical range and are found in all the world’s oceans.
In the summer, populations in the southern hemisphere spend time in the Antarctic feeding.
In the autumn, they begin an annual migratory route to their winter feeding grounds and calving grounds in the warmer tropical waters of the Pacific. They then return in spring. They migrate around 5000km on average.
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24. Migration Humpback whale migration: CfE Higher Biology Metabolism and
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25. Migration Monarch Butterfly migration:
These are the only butterfly known to make a two way migration as birds do.
They are not able to survive the cold winters of North America so they migrate south each autumn to escape the cold.
The monarch butterfly lives for a short time, therefore the butterflies that make the return journey are 3-5 generations removed from those making this journey the previous year.
Successful migration information has been passed on from generation to generation.
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26. Migration CfE Higher Biology Metabolism and Survival

27. Migration
Migratory behaviour is thought to be influenced by both innate and learned behaviour.
Innate behaviour: this is inherited from parents to offspring and is likely to be the biggest influence on successful migration.
Learned behaviour: this is gained by experience. It may come from parents or other members of a social group.
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28. Extremophiles
Organisms that live in extreme conditions that would be lethal to many living things.
They possess enzymes that are tolerant to extreme conditions and function best at high temperatures.
Can you think of an example of such a enzyme?
Taq polymerase used in PCR
Some thermophiles have unique metabolism which allows them to use H2S as an energy source to make ATP.
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29. Extremophiles Types of extremophile Psychrophiles Thermophiles
Alkaliphiles
Halophiles
Acidophiles
Use the cards to match the extremophiles to the diagram and the description.
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30. Extremophile card sort activity
1. Psychrophiles - microbes that live in cold environments such as sea ice, and the Arctic and Antarctic ice packs.
2. Thermophiles - microbes that live in very hot environments such as deep sea vents and volcanic lakes.
3. Alkaliphiles - microbes that live in basic environments such as soda lakes.
4. Halophiles - microbes that live in very salty environments such as salt lakes and salt mines.
5. Acidophiles - microbes that live in acidic environments such as sulfur springs
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31. Environment
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