2.5 Metabolism & Adverse Conditons

Question 1

why is it important that organisms are adapted to survive adverse conditions or are able to avoid them?

Answer 1

So that they can maintain homeostasis

If environmental conditions were out with an organisms tolerable limits, the organism would not be able to generate enough energy to maintain a constant internal environment.

Question 2

describe ‘dormancy’

Answer 2

dormancy is a period of reduced metabolic activity, it allows organisms to observe energy and survive during adverse conditions when the energy costs for normal metabolic activity would be too high

Question 3

what happens during dormancy?

Answer 3

there is a reduction in:
- heart rate
- breathing rate
- metabolic rate
- body temperature

Question 4

describe ‘the two types of dormancy’

Answer 4

Predictive
- this is when the organism becomes dormant before the onset of adverse conditions (common in predictable, seasonal environments)

Consequential
- this is when an organism becomes dormant after the onset of adverse conditions (common in unpredictable environments)

Question 5

trigger stimuli are changes in the environment which cause certain responses in organisms

name some examples of trigger stimuli

Answer 5

• photoperiod (day length)
• light/dark
• tidal changes

Question 6

trigger stimuli are changes in the environment which cause certain responses in organisms

name some examples of trigger stimuli

Answer 6

• photoperiod (day length)
• light/dark
• tidal changes

Question 7

describe ‘the 3 types of dormancy (and if they are predictive or consequential, there trigger stimuli and there description/survival value)

Answer 7

Hibernation
e.g. hedgehog
- period of inactivity (weeks/months)
- metabolic rate drops, minimum energy used
- organism may consume extra food prior to hibernation to build fat stores
- allows organism to survive adverse conditions in winter
- predictive dormancy
- trigger stimuli = photoperiod ad temperature decrease

Aestivavtion
e.g. snails, tortoises and crocodiles
- metabolic rate drops
- organism often burrow with the ground where the temperature is cooler
- allows organism to survive adverse conditions in summer
- consequential dormancy
- trigger stimuli = excessive heat and drought

Daily Torpor
e.g. bats, dogs and humans
- period of reduced activity for part of every 24-hour cycle
- decrease in body temperature, heart rate and breathing rate
- common in organisms with a high metabolic rate
- predictive dormancy
- trigger stimuli = light/dark

Question 8

what is an example of a dormancy in plants?

Answer 8

seed dormancy

Question 9

what does migration mean?

Answer 9

the long distance movement of a species (it allows animals to avoid adverse conditions and usually takes place on a seasonal basis

Question 10

give an advantage and disadvantage of avoiding adverse conditions by migrating

Answer 10

it allows organisms to relocate to a more suitable environment but it requires a lot of energy

Question 11

describe ‘ways in which animals can be tracked’

Answer 11

Satellite Tracking
- lightweight transmitters are glued to the organism’s body/implanted into the skin
- signals are picked up by receivers on the satellites
- organism does not need to be recaptured
- transmitters are expensive
- gives information on migratory routes

Leg Rings
- a band with a unique number attached to a bird’s leg
- if a bird is recaptured, a picture can be built up of its movements or migratory routes

Tagging
- a tag with a unique code can be attached to the underside of the wing
- if a tag is found later, the route and distance covered can be determined

Colour Marking
- bright coloured marks/flags are used
- individuals can be recognised by the combination of colours used
- allows animals to be observed using binoculars so they do not need to be recaptured
- gives information on migratory routes as individuals can be recognised at different locations