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Biology GCSE > Topic 9 - Ecosystems and Interactions Between Organisms > Flashcards

Topic 9 - Ecosystems and Interactions Between Organisms Flashcards

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1
Q

List the different levels of organisms

A

Individual
Population
Community
Ecosystem

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2
Q

What is an individual?

A

A single organism

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3
Q

What is a population?

A

All the organisms of one species in a habitat

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4
Q

What is a community?

A

All the organisms of different species living in a habitat

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5
Q

What is an ecosystem?

A

A community of organisms along with all the non-living conditions

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6
Q

What does abiotic mean?

A

Non-living

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7
Q

What do organisms need?

A

Food

Shelter

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8
Q

What is the definiton of interdependence?

A

Organisms depending on each other for food, shelter and reproduction

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9
Q

Give types of interdependent relationships?

A

Mutualism

Parasites

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10
Q

What is mutualism?

A

A relationship where two organisms both benefit

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11
Q

What is a parasite?

A

An organism which survives and takes what it needs from the host without it benefitting

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12
Q

Give examples of abiotic factors

A

Temperature
Amount of water
Light intensity
Pollution

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13
Q

Give examples of biotic factors

A

Competition

Predation

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14
Q

Give two abiotic factors that could affect the community in an ecosystem

A 
Any two from:
Temperature
Amount of water
Light intensity
Pollution
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15
Q

What is a habitat?

A

A place where an organism lives

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16
Q

What is a species?

A

A group of similar organisms that can reproduce to give fertile offspring

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17
Q

What do you use to study the distribution of small organisms?

A

Quadrats

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18
Q

What is a quadrat?

A

A square frame enclosing a known area

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19
Q

Briefly describe how to study the distribution of small organisms

A

Randomly measure bits of the area

Work out the mean number of small organisms

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20
Q

How do you estimate population size?

A

Population = Mean number of organisms x Area

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21
Q

How can you study distribution along a gradient?

A

By using a belt transect
Mark out the line and measure along it, collect the data
Then calculate the mean amount

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22
Q

What is the source of energy for all food chains?

A

The Sun (light)

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23
Q

How does light get into the food chains?

A

Enters the plants through photosynthesis which is then converted into glucose
The glucose is then either used or stored and passed along the chain as biomass

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24
Q

What is biomass?

A

The mass of living material that makes up an organism

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25
Q

How do plants lose energy on the food chain?

A

By using the glucose for respiration

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26
Q

How do animals lose energy on the food chain?

A

Life processes (eg. movement)
Heating
Respiration

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27
Q

Why doesn’t the energy released by respiration get passed along the chain?

A

Because the energy isn’t stored as biomass

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28
Q

What is each stage of a food chain called?

A

A trophic level

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29
Q

Why isn’t all the energy passed through the chain?

A

Life processes
Not all the animal is eaten (eg. Bones)
Not all the animal can be digested

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30
Q

What does a pyramid of biomass show?

A

How much the creatures at each level of a chain would weigh if you put them together

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31
Q

What happens each time you go up one trophic level?

A

Less number and mass of organisms

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32
Q

What must you remember when drawing a pyramid of biomass?

A

Draw to scale
Producer is always at the bottom
Include the weight of the organisms

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33
Q

Give two reasons why much of the energy in one trophic level is not passed on the next

A

Any two from:
Not all organism is digested
Not all organism can be eaten (eg. Bones)
Organism ‘wasted’ energy on life processes

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34
Q

Calculate the energy lost between the first and second trophic levels
Rosebush = 80,000 kJ
Greenflies = 10,000 kJ

A

= 80,000 - 10,000

= 70,000 kJ lost

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35
Q

What is the efficiency equation?

A

Efficiency = (Energy transferred to next level) / (Energy available at previous level) x 100

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36
Q

Calculate the efficiency of the energy transfer between the first and second trophic levels?
Rosebush = 80,000 kJ
Greenflies = 10,000 kJ

A

= (10,000 / 80,000) x 100

= 12.5%

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37
Q

Calculate the energy transfer between the second and third trophic levels?
Hoverfly larvae = 850 kJ
Bird = 80 kJ

A

= 850 - 80

= 770

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38
Q

What is biodiversity?

A

The variety of living organisms of living organisms in an ecosystem

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39
Q

Why are nitrates added to fields?

A

To fertilise the field

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40
Q

What is eutrophication?

A

An excess of nutrients in water

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41
Q

Describe the process of eutrophication?

A

Excess fertilisers enter the water adding nitrates which causes algae to grow fast and block out the light
Because of the lack of light, plants can’t photosynthesise so they start to decompose
This provides more food to microorganisms which feed and breed taking up oxygen in the water
This causes fish to die

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42
Q

How does fish farming reduce biodiversity?

A

Food produces waste which causes eutrophication
Parasites can be produced
Fish can escape and can cause problems

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43
Q

What is a non-indigenous species?

A

A species that doesn’t naturally occur in that area

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44
Q

How can non-indigenous species be introduced?

A

Intentionally

Unintentionally

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45
Q

Why do non-indigenous species cause problems?

A

Can outcompete indigenous species

Can bring diseases

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46
Q

Suggest how introducing a non-indigenous species could reduce the biodiversity of an area?

A

By outcompetiting indigenous species or by bringing diseases

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47
Q

What ways are there to conserve and maintain biodiversity?

A

Reforestation

Conservation schemes

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48
Q

What is reforestation?

A

The replanting of new trees

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49
Q

What do conservation methods include?

A

Protecting a species’ natural habitat
Protecting species in safe areas
Protecting seeds in a seed bank

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50
Q

What are the benefits of maintaining biodiversity?

A 
Protecting the human food supply
Ensuring minimal damage to food chains
Providing future medicines
Cultural aspects
Ecotourism
Providing new jobs
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51
Q

Explain how reforestation affects biodiversity

A

Provides more food and shelter for different animal species

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52
Q

What factors affect the level of food security?

A 
Increasing human population
Increasing consumption of meat and fish
Environmental changes caused by human activity
Sustainability
New pests and pathogens
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53
Q

Why is eating plants better than meat (biologically)?

A

Plants are the begining of the food chain meaning they have more biomass and energy than meat

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54
Q

How does climate change affect food security?

A

Changes rainfall patterns which affects the growth of crops and reduces yields

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55
Q

How do pests and pathogens affect food security?

A

By causing damage to crops and livestock which reduces the amount of food therefore reducing food security

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56
Q

What happens to materials in an ecosystem?

A

They’re constantly recycled

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57
Q

What do the living things in an ecosystem do?

A

Use the elements from the environment to ‘make themselves’ and turn them into complex compounds

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58
Q

In the carbon cycle, what is the only arrow down?

A

Photosynthesis

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59
Q

In the carbon cycle, what do plants use the carbon for?

A

To make carbs, fats and proteins

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60
Q

In the carbon cycle, how do animals get the carbon?

A

By eating the plants

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61
Q

In the carbon cycle, how do animals give off their carbon?

A

By respiring

By dying and decomposing

62
Q

In the carbon cycle, what happens to dead animals?

A

They are decomposed by microorganisms which releases carbon back into the atmosphere by respiration

63
Q

In the carbon cycle, how does human activity contribute?

A

We burn: plant and animal products, fossil fuels which all release carbon through combustion

64
Q

In the carbon cycle, what does the decomposition mean?

A

That habitats can be maintained as the nutrients are returned

65
Q

Describe the role of microorganisms in the carbon cycle

A

Microorganisms in the carbon cycle are decomposers which break down dead organisms and waste products and release carbon through respiration as they do so

66
Q

In the water cycle, what powers the whole thing?

A

The sun

67
Q

In the water cycle, how does the water turn into water vapour?

A

By the sun heating the land/sea or by the sun heating plants which causes transpiration

68
Q

What is the process of the evapouration of water from a plant called?

A

Transpiration

69
Q

In the water cycle, what happens to the warm water vapour?

A

It gets carried upwards and cools and condenses to form clouds

70
Q

In the water cycle, describe the steps using words

A

Evapouration and transpiration
Condensation
Precipitation

71
Q

What are the methods of preventing droughts?

A

Thermal desalination

Reverse osmosis

72
Q

What does thermal desalination involve?

A

The heating of salt water to evapourate the water leaving the salt behind

73
Q

Define osmosis in turns of salt concentration?

A

Osmosis is the net movement of water particles across a partially permeable membrane from an area of lower salt concentration to an area of higher salt concentration

74
Q

How does reverse osmosis work?

A

By forcing water at extremely high pressure, into a vessel with a partially permeable membrane, which causes the water to move in the opposite direction to osmosis (up the gradient)

75
Q

Briefly describe how to produce clean water through reverse osmosis?

A

Remove the salt water of solids
Send into a vessel with a partially permeable membrane at very high pressure
Collect water with the salts left behind

76
Q

Explain how water from the sea can eventually fall as rain?

A

Heated by sun which causes evapouration, turning water into water vapour
Water vapour rises as hot air rises
Water vapour then cools turning into clouds
Water will then fall from the clouds as precipitation

77
Q

Why can’t nitrogen from the atmosphere be used in plants?

A

Because it is N2 which contains a triple covalent bond which makes it very unreactive that it can’t be used directly

78
Q

What do plants use nitrogen for?

A

Proteins

79
Q

What type of nitrogen do plants use?

A

Nitrates

80
Q

In the nitrogen cycle, what happens to the nitrogen the plants have used?

A

Gets passed along the food chains

81
Q

In the nitrogen cycle, what happens to the nitrogen passed along the food chain?

A

Decomposers break down the: proteins that are found in rotting plants and animals, the urea in animal waste. Which is returned to the soil

82
Q

What is nitrogen fixation?

A

The process of turning nitrogen gas into nitrogen-containing ions in the soil

83
Q

In the nitrogen cycle, how is nitrogen fixated?

A

Lighting

Nitrogen-fixing bacteria

84
Q

In the nitrogen cycle, how does lightning contribute?

A

The energy of the lightning makes nitrogen react with oxygen in the air to give nitrates

85
Q

In the nitrogen cycle, what are the four bacterias involved?

A

Nitrogen-fixing bacteria
Decomposers
Nitrifying bacteria
Denitrifying bacteria

86
Q

In the nitrogen cycle, what do decomposers do?

A

Decompose proteins and urea and turns them into ammonia

87
Q

What do plants do with ammonia?

A

Turns it into ammonium ions

88
Q

In the nitrogen cycle, what do nitrogen-fixing bacteria do?

A

Turn the nitrogen gas into ammonia which forms ammonium ions

89
Q

In the nitrogen cycle, what do nitrifying bacteria do?

A

Turn ammonia in decaying matter into nitrites and then into nitrates

90
Q

In the nitrogen cycle, what do denitrifying bacteria do?

A

Turn nitrates back into nitrogen gas

91
Q

Describe the benefit of denitrifying bacteria?

A

No benefit to living organisms

Only benefit is that it provides the nitrogen cycle

92
Q

In the nitrogen cycle, what is the only arrow up?

A

Denitrifying bacteria

93
Q

Where are denitrifying bacteria found?

A

Waterlogged soils

94
Q

Where are nitrogen-fixing bacteria found?

A

Soil

Nodules on the roots of legume plants

95
Q

Give examples of legume plants?

A

Peas and beans

96
Q

Describe the relationship between legume plants and nitrogen-fixing bacteria?

A

Mutualistic

97
Q

Why are legume plants and nitrogen-fixing bacteria mutualistic?

A

The plant supplies the bacteria with food (sugars), whilst the bacteria supplies the plant with nitrogen-containing ions which can be used to make proteins

98
Q

Why doesn’t the nitrogen cycle work with farms?

A

Because the crops are harvested instead of being left to die and decompose so the nitrogen they contain isn’t returned to the soil

99
Q

What does lack of nitrogen content in the soil lead to?

A

Poor crop growth and deficiency diseases

100
Q

Why must farmers use methods to increase nitrate content?

A

Because the crops are harvested instead of being left to die and decompose which will lead to poor crop growth and deficiency diseases as there will be no nitrogen returned to the soil

101
Q

How do farmers provide nitrogen to the soil?

A

Crop rotation

Fertilisers

102
Q

Give examples of fertilisers

A

Animal manure

Compost

103
Q

How do fertilisers increase nitrogen content?

A

By providing substances which have nitrates in them which adds nitrates to the soil

104
Q

Why aren’t artifical fertilisers as popular?

A

They are alot more expensive

105
Q

How does crop rotation increase nitrate content?

A

Nitrogen-fixing crops are planted for a period of time putting nitrates back into the soil for another crop to use for a period of time

106
Q

What does crop rotation involve?

A

Swapping a normal crop with a nitrogen-fixing crop every once in a while to replenish the nitrogen content of the soil

107
Q

Give examples of nitrogen-fixing crops

A

Peas and beans

108
Q

Describe how nitrogen compounds in dead leaves are turned into nitrates in the soil?

A

Decomposers turn the urea and protein into ammonia

Then nitrifying bacteria turns the ammonia into nitrites which is then turned into nitrates

109
Q

What does the number of stonefly larvae tell you?

A

How clean the water is

110
Q

If you find stonefly larvae in a river what does that tell you?

A

The water is clean

111
Q

What does the number of blood worms tell you?

A

How polluted the water is

112
Q

If you find blood worms in a river what does that tell you?

A

The water is polluted

113
Q

Give examples of organisms which indicates water is clean

A

Stonefly larvae

Freshwater shrimps

114
Q

Give examples of organisms which indicates water is polluted

A

Blood worms

Sludge worms

115
Q

What organisms can be used to monitor the concentation of sulfur dioxide

A

Lichen

116
Q

What does the number of lichen tell you?

A

How clean the air is

117
Q

If you find alot of lichen what does it tell you?

A

The air around you is very clean

118
Q

What does the number of blackspot fungus tell you?

A

How clean the air is

119
Q

If you find alot of blackspot fungus what does it tell you?

A

The air around you is very clean

120
Q

Give examples of organisms which indicates the air is clean

A

Lichen

Blackspot fungus

121
Q

What are the flaws of indicator species?

A

No accurate figures

Other factors causing increase or decrease in number of species

122
Q

How can you use indicator species to measure pollution?

A

Count the number of species or doing a survey to see if a species is present or absent

123
Q

What doesn’t checking an area for a species absence or presence tell you?

A

How polluted the area is

124
Q

What are the pros of using indicator species?

A

Cost-effective

Simple

125
Q

What are non-living indicators of pollution?

A

Dissolved oxygen meters and chemical tests

Electronic meters

126
Q

A gardener finds blackspot fungus on the leaves of her rose plant
Explain what this indicates about the local air quality

A

That the air is clean as the fungus is very sensitive to the level of sulfur dioxide

127
Q

What type of organisms decompose?

A

Fungi and bacteria

128
Q

What does the rate of decay depend on?

A

Temperature
Water content
Oxygen availability

129
Q

Why does temperature affect rate of decay?

A

Because the temperature affects the rate of enzyme-controlled reactions in microbes so decay happens at different speeds depending on the temperature

130
Q

Why does water content affect rate of decay?

A

Decay takes place faster in moist conditions because the organisms involved in decay need water to survive and carry out biological processes

131
Q

Why does oxygen availability affect rate of decay?

A

Because most organisms involved in decay need oxygen for aerobic respiration which releases the energy needed for the decay to take place

132
Q

How do we reduce the rate of decay?

A

Storing food in fridges/freezers
Storing food in airtight cans
Drying food
Adding salt/sugar

133
Q

How does freezers/fridges reduce rate of decay?

A

The cold temperature slows down the decomposers’ rate of reproduction or stops it altogether

134
Q

How do airtight containers reduce rate of decay?

A

To stop microorganisms getting in, and if they were to get in the lack of oxygen would most likely kill them

135
Q

How does drying the food reduce rate of decay?

A

By removing water that microorganisms need to survive and reproduce

136
Q

How does adding salt to food reduce rate of decay?

A

By causing the water to leave via osmosis meaning the microorganisms lose water needed to survive and reproduce

137
Q

What is compost?

A

Decomposed organic matter

138
Q

When is compost produced quickest?

A

Warm and moist conditions with plenty of oxygen

139
Q

Name three things that affect the rate of decay

A

Temperature
Oxygen availability
Water content

140
Q

What does it mean if two species are interdependent?

A

They depend on each other

141
Q

Give twp biotic factors and explain how each one could affect a community?

A

Competition - the stronger organisms will survive
Predation - if predators increase, prey decrease causing predators to decrease causing prey to increase (negative feedback)

142
Q

Explain why food chains rarely have more than five trophic levels?

A

As you go up each trophic level there is less energy available until you get to the top bit where there is not enough energy for the predator to kill the prey

143
Q

What is the formula for calculating the efficiency of energy transfer between trophic levels?

A

(Energy to next level / Energy available at previous level) x 100

144
Q

Give four ways in which fish farms can reduce biodiversity

A

Waste causing eutrophication
Parasites breeding and getting out
Predators dying in the nets
Escaping of fish which become indigenous species

145
Q

What is meant by the term food security?

A

The state that we have access to enough food that is safe for us to eat and has the right balance of nutrition

146
Q

Name the process that removes carbon from the air?

A

Photosynthesis

147
Q

Name two processes which put carbon back into the air

A

Any two from:
Combustion
Respiration
Decay

148
Q

Name a common method of desalination

A

Thermal desalination

149
Q

Describe the role of nitrogen-fixing bacteria in the nitrogen cycle

A

Turns nitrogen gas into ammonia which forms ammonium ions

150
Q

Why is crop rotation beneficial to farmers?

A

Replenishes nitrogen content in ground, saving money which would of been spent on fertilisers whilst also providing a crop to sell

151
Q

Explain why cold conditions can help to preserve foods

A

The cold conditions prevent/slow reduce the survival and reproduction of the microorganisms

152
Q

Give three ways of increasing the rate of decomposition of compost?

A

By making the conditions more:
Moist
Warm
Oxygen plenty

Biology GCSE (9 decks)

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