2.5 Metabolism and Adverse Conditions

Question 1

In some environments extremes of temperatures can result in what?

Answer 1

in a lack of food and drought

Question 2

How do they cope with these fluctuations?

Answer 2

to cope with these fluctuations which can be cyclic or unpredictable, organisms have adaptations to survive them or to avoid them

Question 3

What is dormancy?

Answer 3

(surviving adverse conditions)
to allow survival during a period when the energy costs required for normal metabolic activity would be too high, the metabolic rate can be reduced
this can be achieved by a period of dormancy
dormancy is part of an organisms lifecycle and can be predictive or consequential

Question 4

What is predictive dormancy?

Answer 4

predictive dormancy is when an organism becomes dormant before the onset of adverse conditions and is usually genetically determined
it is typical of predictable seasonal environments where the temperature and photoperiod can be used as environmental triggers

Question 5

what is photo period?

Answer 5

number of daylight hours

Question 6

what is consequential dormancy?

Answer 6

when an organism becomes dormant after the onset of adverse conditions
it is a typical response of organisms living in unpredictable environments

Question 7

What is leaf loss?

Answer 7

some plants lose their leaves and enter a period of dormancy (inactivity) when the climatic conditions are not suitable for growth e.g. during cold winters or summer drought

Question 8

What is seed dormancy?

Answer 8

the seeds of some plant species display periods of dormancy when they fail to germinate even under ideal conditions
ideal conditions - Water Oxygen Warmth
This can be due to the presence of chemical inhibitors which prevent the growth of the embryo plant or to the presence of an impermeable seed coat which forms a physical barrier to the uptake of water

Question 9

What does hibernation allow animals to do?

Answer 9

to survive cold winter conditions and involves the lowering of body temperature, heart and breathing rates and oxygen consumption. This lowers metabolic rate at a time when food is limited

Question 10

What happens before hibernating?

Answer 10

a mammal eats extra food and stores it as fat.

the fat is used up as an energy source during hibernation

Question 11

Why do homeostatic mechanisms remain active during hibernation?

Answer 11

homeostatic mechanisms remain active during hibernation - maintaining a lower body temperature to prevent freezing

Question 12

What does decreasing photoperiod act as?

Answer 12

trigger for hibernation

Question 13

What is daily torpor?

Answer 13

some animals undergo short periods on a daily basis when their body temperature, heart and breathing rates and oxygen consumption are lowered

Question 14

Benefit of daily torpor?

Answer 14

conserves energy between feeding or may occur at night when temperature falls

Question 15

Daily torpor is common in what animals?

Answer 15

this type of behaviour adaptation is typical in small animals with high metabolic rate e.g. humming bird

Question 16

Explain Daily torpor in humming birds?

Answer 16

humming birds have an extremely high metabolic rate with a heart rate that can exceed 1200 beats per minute. Their energy consumption is so great that humming birds use daily torpor to conserve energy in tropical conditions

Question 17

What is aestivation?

Answer 17

aestivation is a form of dormancy that allows some animals to survive in periods of high temperature or drought in summer when food or water may become scarce.

Question 18

What does aestivation typically involve?

Answer 18

involves burrowing into the ground where moisture levels are higher and temperatures are lower than on the surface

Question 19

Why does aestivation require less energy than hibernation?

Answer 19

to maintain a minimum body temperature and so the animal does not require a large store of body fat
e.g. snails, earthworms, lizards and some tropical butterflies

Question 20

Example of aestivation: Water holding frog?

Answer 20

the water holding frog buries itself in sandy ground in a secreted, water tight, mucus cocoon during periods of hot dry weather and remains in this state until the arrival of rain and conditions improve

Question 21

Example of aestivation: Lungfish?

Answer 21

lungfish is an example of a species showing aestivation which allows them to survive without water for up to 3 years. They have lungs as well as gills allowing them to breathe air. When its lake dries up the fish burrows into the mud, secreting mucus covering its entire body. The mucus dries up to from a sac holding the moisture in even when the mud dries completely. The lungfish stays moist and breathes through a mucus tube.

Question 22

TOPTIP

Answer 22

In predictive dormancy the organism enters dormancy before the adverse conditions begin
In consequential dormancy the organism enters dormancy after the adverse conditions begin

Question 23

When does migration usually take place?

Answer 23

migration is a relatively long distance movement of individuals which usually take place on a season basis

Question 24

What does migration enable animals to do?

Answer 24

to avoid metabolic adversity brought about by lack of food and low temperatures or predation by expending energy to relocate to a more suitable environment

Question 25

What is migration?

Answer 25

migration is a regular pattern of behaviour displayed by
birds - swallows, geese, osprey
mammals - bison, wildebeest
fish - salmon

Question 26

What are factors that trigger migration?

Answer 26

change in photoperiod
change in temperature
change in food availability
genetic factors

Question 27

What is Inate behaviour?

Answer 27

timing and direction of migration 
inherited 
carried out by all individuals in a species
triggered by an external stimulus
inflexible

Question 28

What is learned behaviour?

Answer 28

stopover feeding sites and changes to route during migration
develops as a result of experience
watching others or trial and error
flexible

Question 29

TOPTIP

Answer 29

Migration is influenced by both inate and learned behaviour

Question 30

Examples of Tracking methods?

Answer 30

direct observation 
radio tracking 
satellite tracking
marking 
radar
sonar

Question 31

Explain Direct Observation?

Answer 31

Visual identification of species and estimation of numbers along a migration route
Limited by need to see animals to restricted to daytime

Question 32

Explain Radio Tracking?

Answer 32

Uses a transmitter of radiowaves attached to the animal. Scientists use a receiver to pick up the signal and follow the migration
Limited by the need for the scientist to be within range to receive the signal

Question 33

Explain satellite tracking?

Answer 33

uses a transmitter attached to the animal and receivers on orbiting satellites which relay to receivers on Earth
allows migration to be tracked remotely

Question 34

Explain Marking?

Answer 34

Animal is tracked and tagged
on re capture, information on weight, health and location can be compiled
limited as very large number of re-captures animals are needed for reliable results

Question 35

Explain Radar?

Answer 35

Pulses of electromagnetic waves are emitted from an antennae allowing echo location to track a group of migrating individuals; allowing location and distances to be calculated
can be used remotely

Question 36

Explain Sonar?

Answer 36

sensors detect underwater sounds
passive - used to identify species
active - emits sounds to calculate distance/ direction/ position of individual

Question 37

TOP TIP

Answer 37

make sure that you know the difference between surviving adverse conditions and avoiding them

Question 38

Explain the difference between innate and learned behaviour?

Answer 38

innate behaviour is inherited, learned behaviour occurs as a result of trial and error experiences

Question 39

What are extremophiles?

Answer 39

prokaryotes such as bacteria which are able to tolerate extremes of temperature, pressure, salinity and pH within their environments are called extremophiles

they can thrive in conditions which would be lethal to other organisms

this is a result of the evolution of enzymes within their cells which are tolerant of extreme conditions

Question 40

What would’ve caused these enzymes to be produced?

Answer 40

expression of genes coding for the production of the enzymes; transcription and translation

Question 41

What are enzymes from cryophiles or psychrophiles (cold living organisms) used for?

Answer 41

used to enhance the cleaning power of biological washing detergents at cold detergents

Question 42

TOP TIP

Answer 42

PCR
heat tolerant DNA polymerase is extracted from a thermophile; a species of bacteria which lives inside rims of volcanoes. This enzyme is not denatured by temps used in thermocycling

Question 43

What are methanogens?

Answer 43

methanogens are bacteria which live in low oxygen niches (anaerobic conditions) e.g. the digestive system of humans and ruminants, hot springs, hydrothermal vents and under layers of ice
they generate ATP and methane from hydrogen and CO2

Question 44

What is sulphur bacteria?

Answer 44

live in hot springs and seabed vents
able to generate ATP from high energy electrons from inorganic molecules such as hydrogen sulfide gas
example: snotties are colonies of single-celled bacteria that hang from the walls and ceilings of caves
they generate ATP from hydrogen sulphide and produce sulphuric acid

Question 45

TOP TIP

Answer 45

to generate ATP, some extremophiles are able to remove high energy electrons from inorganic molecules

Question 46

Meaning of dormancy?

Answer 46

dormancy is part of an organisms lifecycle and is the stage associated with resisting/tolerating periods of environmental adversity

Question 47

Describe one application of an enzyme extracted from a thermophilic bacterium?

Answer 47

taq polymerase - PCR