MONITORING THE ENVIRONMENTENERGY FLOW

NUTRIENT TRANSFER

Energy Flow

Learning Outcomes

• understand that radiation from the Sun is the source of energy for most ecosystems / communities of living organisms and that green plants, and other photosynthetic organisms such as algae, capture a small percentage of the solar energy which reaches them.

Food Chains

• Food chains are one way of showing how organisms interact.

Grass Rabbit Fox

• The arrows represent the transfer of energy between organisms.

Food Chains

• Plants are producers because they make their own food

• Animals are consumers because they eat food to obtain energy.

Consumers and Decomposers

• There are 3 types of consumer– Herbivores eat plants– Carnivores eat other animals– Omnivores eat plants and animals

• Organisms that breakdown dead plants and animals are called decomposers– e.g. fungi and bacteria

Producer primary secondary tertiary consumer consumer

consumer

• Each feeding level is known as a trophic level

Energy in the Ecosystem

• The sun is the main source of energy for food chains

• Photosynthetic organisms capture a small percentage of the solar energy which reaches them and convert this into chemical energy.

• This chemical energy is then available to other organisms.

Light energy available to the plant

• Of the 100% solar energy reaching the Earth only some is trapped by chlorophyll

• What happens to the rest? – Reflected by clouds or dust in the air– Reflected by plants– Does not fall on leaves– Wrong wavelength for chlorophyll to trap

– Pass through leaves

Energy Flow through an ecosystem

• Energy is transferred from one organism to another.

• This is shown in food chains and food webs

• Energy given out by organisms is lost to the environment.

Pupil Activity Food Chains and energy in living systems

• Colour in the handout• Answer the questions below in full

sentences1. In a cool, wet summer the hedgerow insect

population is low. Why will fewer young weasels be born that spring survive?

2. Simple food chains of the type shown, are uncommon, why?

3. Why does the amount of energy flowing through the food chain fall so much between each level?

Prep: Food Chains and Energy Flow

• Read all the information provided• Answer questions 1 – 7

• This is due in on Wednesday 18th May 2011

Learning Outcomes

• Investigate data about food chains and food webs and understand that they show the transfer of energy between organisms and involve producers; first, second and third stage consumers; herbivores and carnivores.

Energy Flow – Progress question

• What is the source of energy for ecosystems?

• How does energy from that source become available to a predator like a tiger?

Food chains show the flow of energy through an ecosystem

Plants are at the start of every food chain

Food Webs

• If food chains in a habitat are linked, they form a FOOD WEB.

Food web for a single tree

Changing Food Webs

• Look at the two examples of ecosystems given.

• For each question give a suggestion of what might happen to the populations of organisms and explain why you think this.

Changing food webs

Changing food webs

Food Webs

• Food webs are easily unbalanced if one population of organisms in the web disappears due to:– Over-predation or hunting– Disease– Pollution– Use of pesticides– Lack of food– emigration

Past Paper Question (grade B)

• Answer the question on Sandeels• 4. (a)

– decrease the numbers (of sandeels) [1]– sandeels are eaten by herring [1]– herring compete with sandeels for

(animal) plankton/feed on plankton [1]

• (b) 3 effects are looked for in the answer from:– herring compete with birds for sandeels/reduce number

of sandeels;– sandeels do not have enough food / (animal) plankton;– rise in sea temp (global warming) affect plankton

distribution or numbers;– fishing for sandeels;– Not enough food for birds as numbers of sandeels

dropping.– (not: ref. bird breeding rate unqual./ref. herring killing

sandeels)

• (c) quotas for sandeel fisheries / sandeel fishing ban or protected species/ marine or nature reserves [1]

• (not: captive breeding/increase number of seals/fishing ban unqual.)

Learning Outcomes

• understand that at each stage in the food chain energy is used in repair and in the maintenance and growth of cells whilst energy is lost in waste materials and as heat during respiration.

Energy Loss in a food chain

• Energy is lost at each level in the food chain – Respiration (lost as heat)– Used up in movement– Maintaining constant body temperature– Faeces and urine (lost as heat)– Some material not being eaten by the

consumer

Energy loss in a food chain

• 90% of energy is lost at each level in a food chain

Tree aphid ladybird little bird big bird 100 10 1 0.1 0.01

Energy units

• In long food chains, very little energy is left for the top carnivore

• In short food chain, less energy is lost.

Energy losses from an animal

• Herbivore

Energy losses from an animal

• Carnivore

Shortening the food chain

• The fewer the trophic levels, the less food energy is lost so the more food is available to consumers.

Shortening the food chain

• Energy transfer between producers and consumers is inefficient because:– Some plant material is not digested and passes

out of the herbivore body as faeces– The herbivore uses energy to stay alive– When the herbivore dies, its body represents

“locked up” energy, which transfers to decomposers

Pupil Activity

• Practice question on food chains and energy flow.

Learning Outcome

• use data to construct and interpret pyramids of numbers and biomass.

Food Pyramids

• Each trophic level is represented by a horizontal bar

• The width of the bar represents– The number of organisms– The amount of biomass

• The base of the pyramid represents the producer

• The second level is the primary consumer, etc

Pyramids of number

• This represents the relative number of each type of organism at each trophic level.

• Draw a pyramid of number for each of the three food chains below:

– Grass antelope lion

– Oak tree caterpillar blue tits owl fleas

– Rose bush aphid ladybird blackbird

Pyramids of number

• Pyramids of number can be inverted as they do not take into account the size of the organism.

• Pyramids of Biomass take into account the number of organisms and their size.

• Pyramids of biomass are never inverted.

Pyramids of Biomass

• This represents the amount of living material (biomass) at each level.

• Draw a pyramid of biomass for each of the three food chains below:

Grass antelope lion

Oak tree caterpillar blue tits owl fleas

Rose bush aphid ladybird blackbird

Practice Questions on Pyramids

• Collect – a question sheet– A sheet of A4 paper– Graph paper

Nutrient Transfer

Learning Outcomes

• understand that carbon is constantly cycled in nature by the carbon cycle via photosynthesis which incorporates it and respiration which releases it.

Nutrient Cycling

• Materials are returned to the environment in waste materials or when living things die and decay.

• We say that they are recycled.• This decay is caused by organisms:

– Detritivores e.g. worms– Decomposers e.g. bacteria and fungi

• These release enzymes which are adapted to breakdown material

• For decay to be successful the following conditions are required.– Oxygen – for respiration– Warmth – bacteria will reproduce more quickly,

increasing the number of decomposers. – Water

• For normal life processes• To secrete solutions of digestive enzymes• To absorb the products of digestion

• Most living matter is made up of just 6 elements; carbon, hydrogen, oxygen, nitrogen, phosphorous and sulphur.

• Living things need these elements to make proteins, carbohydrates and fats.

Fossil fuels

Coal, oil, gas, peat

Combustion (burning)

Carbon dioxideIn the air (CO2)

photosynthesis

respiration

Carbon compounds in plants

Carbon compunds in animals

decay

feeding

The carbon cycle

Past Paper Questions

• 2 • (a)

– (i) Two from: leaves, grass, twigs [1]– (ii) Compost [1]– (iii) Improve soil (not: fertiliser) [1]

• (b) – (i) Bacteria/fungi (not: mould) [1]– (ii) Oxygen [1]– (iii) heat from respiration

Past Paper Questions

• 5 • (a) A burning [1] B photosynthesis

[1]• (b)

– (i) Increase/rise [1]– (ii) Global warming / acid rain (spec) / accept

greenhouse effect [1](not: pollution/greenhouse gas/specific examples e.g. melting ice caps/ increase in temperature)

Past Paper Questions

• 5. – (a) (i) Clockwise – burning, respiration, feeding,

photosynthesis [4 × 1]– (b) bacteria / fungi / decomposers [1]

(not: microbes/worms)– (c) deforestation / increase burning fossil fuels / increase

in traffic / increase in power stations [1] (not: cutting down trees)

• (d) – (i) killing fish / trees/ tops of pine trees turn yellow [1]– (ii) lung disease [1

Past Paper Questions

• 4 – (a)

• bacteria and fungi 1 mark each [2] • (allow: decomposers for 1 mark, no mark for

bacteria/fungi as well)

• (b) – (i)

• Respiration 2 [1]• Combustion 1 [1]• Photosynthesis 3 [1]

– (ii) feeding/ingestion [1](not: digestion/food chain/nutrition)

Learning outcomes

• know that microorganisms, bacteria and fungi, feed on waste materials from organisms and that when plants and animals die their bodies are broken down by microorganisms bringing about decay. These microorganisms respire and release carbon dioxide into the atmosphere.

• Understand what happens when decay is prevented. Burning fossil fuels releases carbon dioxide.

• Microorganisms digest materials from their environment for growth and other life processes.

• These materials are returned to the environment either in waste products or when living things die and decay.

• When decay is prevented substances such as peat, coal, oil and gas are formed and these store energy in carbon compounds (Fossil Fuels)

• Energy and carbon dioxide are released when these fossil fuels are burnt

• In the last 200 years, humans have extracted and burnt fossil fuels, increasing the levels of carbon dioxide in the atmosphere.

Possible investigations:

• Investigate the decay of leaves in different environmental conditions e.g. soil pH, temperature and in bags of different mesh size.

• Experiments to investigate the microbial decay of fruit or vegetables.

Nitrogen Cycle

Learning Outcomes

• understand that nutrients are released in decay, e.g. nitrates and phosphates, and that these nutrients are then taken up by other organisms resulting in nutrient cycles. In a stable community the processes which remove materials are balanced by processes which return materials. .

Decay and Recycling

• All minerals in living things are recycled.– Plants take these minerals from their

environment– Animals take them in as food– These minerals are recycled when dead plants

and animals decay.

• This maintains a balance between living things and the environment.

• Nitrates and phosphates are important substances to living things

• The nitrogen cycle and the phosphorous cycle ensure that the minerals are recycled.

Learning outcomes

• understand that nitrogen is also recycled through the activity of soil bacteria and fungi acting as decomposers, converting proteins and urea into ammonia. This is converted to nitrates which are taken up by plant roots and used to make new protein.

The Nitrogen Cycle

• Plants and animals need nitrogen to make proteins.

• Nitrogen gas is unreactive and can not be used by living things

• Nitrogen gas must be changed to nitrates before it can be used by plants.

• Animals then eat plants

The nitrogen cycleNitrogen gas in the

air

Nitrogen fixation

Nitrates in soil

Nitrogen fixing bacteria in the soil

Nitrogen fixing bacteria in root nodules

Nitrifying bacteria

Decay bacteria break down proteins and release ammonia

Plant proteinAnimal protein

Animal wastes

Denitrifying bacteria

Nitrogen fixation

• Making nitrates from the nitrogen gas in the air

• Nitrogen-fixing bacteria found in the soil and in the root nodules of leguminous plants, such as peas, beans and clover

Nitrogen Fixation

Feeding

Decay

• Nitrogen compounds in living things are returned to the soil as ammonium compounds through: – excretion and egestion by animals – the breakdown of dead plants and animals by decay

bacteria

Nitrifying bacteria

• Change ammonium compounds to nitrates

decay

decay

Denitrifying bacteria

• Denitrifying bacteria live in water logged soils.

• They change nitrates back into nitrogen gas.

denitrification

The bacteria

• The nitrogen cycle involves four different types of bacteria– decay– Nitrifying– Denitrifying– Nitrogen-fixing

• In an exam, you will need to be able to describe the roles of these bacteria

Leaching

• Some nitrates may be washed out of the soil by rainwater, this is called leaching.

• Leaching can lead to the eutrophication of lakes

Learning Outcome

• investigate the action of urease on urea.

Urease and decay

• Decomposers secrete enzymes into the soil to breakdown waste.

• The enzyme urease can cause decay by breaking down urea to form ammonia and carbon dioxide

• Ammonia dissolves in water to form an alkaline solution.

• In an experiment the action of urease can be investigated using universal indicator paper

How does urine help keep the nitrogen cycle going?

• This practical is designed to help you– Draw conclusions– Judge the strength of evidence– Understand control experiments

How does urine help keep the nitrogen cycle going?

• Alternative name to practical– Investigating the effect of the action of urease

on urea.

• Collect the instruction sheet• Read through all instructions• Draw a results table• Collect your equipment• Start the investigation

Analysis of Investigation• What are your conclusions from this experiment?• How certain are you of these conclusions? Give

reasons for your answers.• Why do you think that ethanoic acid was added to

the tubes?• What was the point of tube D?• How could you have improved the reliability of

your results?• In this experiment, different volumes were used

to vary the concentration of urease. Suggest how this method could be improved.

Monitoring the Environment

Learning Outcomes

• understand the issues surrounding the need to balance the human requirements for food and economic development with the needs of wildlife.

The Environment

• The environment includes– All living things– All habitats

• place where living things live

– The climate• The physical factors

• All of these things are interlinked• A change in one factor can have

effects on the others

Conservation of Wildlife

• Is this a good thing?– In pairs discuss the conservation of

wildlife– List the possible advantages and

disadvantages of conserving wildlife

Conservation of wildlife

• Conflicts can arise when– Conservation measures means a

disadvantage for the human population– Conserving one species means another

suffers• Example

– Humans need housing– Building houses will destroy animal and

plant habitats

Learning Outcomes

• Discuss how the collection of detailed, reliable scientific information and monitoring by biologists could help to inform, manage and reduce the impact of development on the environment e.g. the role of the Environment Agency.

Conflicts between humans and conservation

• Humans need food– Habitats are

converted into farmland, which reduces the number of species that can live there

• Humans need alternative energy sources– Structures built can

destroy or alter natural habitats

Getting the balance right

• Environments are constantly changing – they are dynamic

• The Environment Agency monitors the environment and the human impact.

• The Environment Agency has an important role in – monitoring, protecting and improving the

environment, – promoting sustainable development.

Monitoring the environment

• Before any development, scientific information must be collected on– The state of the environment– What changes could occur– The impact of these changes on the species

• This is presented in a document called an Environmental Impact Assessment.

E.I.A

• EIA – assessment of potential

environmental damage

Cardiff Bay Barrage

• Read through the information provided– Summarise the benefits and

disadvantages of the barrage– In pairs, discuss whether or not it was

right to build a barrage across Cardiff bay.

How Science Works Task

• Since moving their feeding ground, survival rate of the common redshank has gone down from 85% to 78%.

• It is possible that this is because the food supply on the new feeding ground is not as good as in Cardiff Bay.

• What information would scientists need to collect before they could confirm this hypothesis?

Redshank

Research and use of informationPREP TASK

• Research information on the Allt Duine Wind Farm– Use a google search– Bring the information to lesson with you next

week– You will be given 45 minutes in lesson time

next week to write a report– There is information on the students P Drive

(for emergency use)– Do not bring in too much information –

although you do not know the question you are going to have to research you can sieve through information and bring in relevant unbiased information.

Research and use of informationClass Task

• Part A– Using the information which you found, write a

brief report about the proposed development of a wind farm at Allt Duine

• Part B– Devise a method to find out how many people

who live or use the area support the proposed development.

Learning Outcomes

• discuss the advantages and drawbacks of intensive farming methods, such as using fertilisers, pesticides, disease control and battery methods to increase yields.

Intensive Farming Methods

Intensive Farming Methods

•Modern farming is intensive– This means that farmers produce

as much food as possible by making the best use of available land, plants and animals

Battery farming•Animals are reared in controlled

conditions– Amount and type of food

• High protein diets with additives

– Temperature of surroundings kept constant

– Restrict movement– Antibiotics put in food to control disease

Advantages

• Produces more food on available land• Huge variety of top quality foods• Production of foods all year round• Cheap prices• No longer the risk of having to ration

food

Drawbacks

• Habitat destruction– Remove hedgerows to make large fields to maximise efficiency

• Soil erosion• Use of fertilisers

– Eutrophication

• Use of pesticides– Disrupt food chains

• Battery farming, such as hens and crated veal calves– Ethics – is this humane?

Fertilisers

Learning Outcomes

• understand that untreated sewage and fertilisers may cause rapid growth of photosynthesisers, plants and algae, in water. When the plants and algae die, the microbes, which break them down, increase in number and further use up the dissolved oxygen in the water. Animals, including fish, which live in the water may suffocate

Fertilisers•Fertilisers containing nitrates wash

into rivers and streams•The result is a river enriched with

nutrients, this is known as eutrophication

The stages that follow eutrophication

• rapid plant growth • plant death• increase in microbes• Decrease in oxygen as microbes

respire• Death of fish and invertebrates

Pesticides

Pesticides•used to kill insect pests to reduce

damage to crops•Also kills non target insects, which

may have been useful•Shortage of food for insect eating

birds•Pesticides can enter the food chain

Pesticides and Food Chains

• Pesticides are used to kill pest species– Insecticides kill insects– Herbicides kill weeds

• Pesticides stay in the ecosystem for a long time, they are not biodegradable

• This can have a devastating effect on wildlife.

Bioaccumulation

• pesticides are poisonous to other animal life. • If the animals at the start of a food chain take

up small amounts it becomes more and more concentrated higher up until it can kill the animals at the top

For information only

• One example was the use of a pesticide called DDT used in the 1960's.

• It was used to kill insects (an insecticide) that were damaging crops but it leaked into rivers and contaminated plants.

• The small animals and fish further up the food chain collected more and more because it wasn't lost (not excreted) from their bodies.

• Eventually, otters ate the fish and were killed. Otters were virtually made extinct in Southern England.

TB in Cattle

Learning Outcomes

• Investigate the issues surrounding the question of the source of TB infection in cattle, including the role of the scientific community in planning valid experiments in order to inform policy decisions and how different interpretations can be applied to reach various possible outcomes.

Badgers and Bovine Tuberculosis

• The facts– Badgers carry Bovine TB and pass it on

to cattle– If badgers in an area are culled, bovine

TB is significantly reduced– It’s difficult to kill every badger in an

area– Badgers can move to surrounding areas

increasing bovine TB in those areas.

Culling Badgers

• Is it possible to obtain evidence about the source of infection?

• Is it proven that badgers are responsible for TB in cattle?

• If badgers are culled would new populations fill the vacant niches?

• If badgers are culled would TB actually spread to new areas?

• Is vaccination of cattle and or badgers a possible method of control?

Exam Question bTB

• (a) (i) – because badgers could move into the area/new

areas (to fill vacant niches) – because of the movement of cattle between

herds/one farm to another. [1]

• (ii) – because it would remove a possible source of

the infection in cattle– cattle can be infected by badgers. [1]

• (b) – badgers are protected by law – they consider the evidence is unreliable– Culling doesn’t control bTB– farmers could do more to protect their herds– Vaccination– ref. animal rights or inhumane [1

• not: – ref. endangered species / – extinction of badgers / – cruelty

• (c) – vaccination – more reliable (tuberculin) testing – check cattle when sold– More control on cattle movement– culling infected herds. [1]

• not: – killing cattle

RESEARCH AND USE OF INFORMATION

• Farmers can not kill badgers unless they get a licence from the Government. In 2010 farmers in some areas of Wales were licensed and there was a proposal to allow English farmers to cull badgers, too.

• On the basis of scientific evidence, what do you think the UK government’s policy on badger culling should be?

• Use the internet to research Bovine TB and badgers – bring any print outs with you to the next lesson.

Pollution

Pollution

• Pollutant– Substance added to environment which

damages it in some way– Can be natural or unnatural

Common pollutants

• Oil• Detergents• Fertilisers• Pesticides• Heavy metals• Carbon dioxide• Methane• CFCs

• Sulfur dioxide• Nitrous oxides• Human and animal

sewage• Noise• Heat• Non-recyclable

household waste

Indicator Species

Learning Outcomes

• investigate using suitable data, how indicator species and changes in pH and oxygen levels may be used as signs of pollution in a stream

Pollution Indicating Species

• A Pollution Indicator is any living organism that shows the presence of environmental pollution.

• Species vary significantly between clean and polluted areas.

• Pollution levels in a river can be monitored by looking at the species of organisms living there.

Freshwater indicator species

• A large population of tubeworms in a river tells us that there are low oxygen levels.

• They are red in colour because they contain haemoglobin

• This helps them to absorb dissolved oxygen from the water.

red tubeworms

Chemical Indicators

• Oxygen levels can be a measure of pollution.

• pH is also measured to find out how clean water is.

• A data logger can be used to measure these things. Data logger

Trent Biotic Index

This is a standard method of measuring pollution. It is based on the fact that different organisms can resist different degrees of pollution.

The table shows an interpretation of Trent Biotic Index results.

Index State Typical Animals

XI-X Very clean Trout, salmon

VII-X Clean Fish and various arthropods

VI-VII Clean As above but fewer species

V-VI Fairly clean A few fish, freshwater fleas

III-IV Dubious As above but fewer species

II-IV Dubious As above but only fish

I-III Poor Insect larvae and tubeworms

0-I Poor Anaerobic organisms only

11

22

33

44

11 15

5

12

02

0

0

0 0

3

4

616

12

3

0 0

3

8

814

2

0

0 0

5

12

25

0

0

The case of a polluted riverClick the numbers on the river to see the effect of the pollution which has happened between locations and on the population of different organisms.Use this data to plot a graph and write a conclusion.

Click on the graph icon above

to plot a graph

1

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18

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1

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3 42

Bar graph to show the effect of the pollution on the population of different river organisms.

Number

1 3 42 1 3 42 1 3 42 1 3 42 1 3 42 1 3 42 1 3 42

Back to the data

Click the numbers in order to record the number of organisms

Practical testing water for organic pollutants

• Sewage or fertiliser pollution causes an increase in the number of bacteria in water.

• These bacteria produce an enzyme, catalase, which breaks down hydrogen peroxide in their cells into water and oxygen.

• Polluted water, with more bacteria, will break down hydrogen peroxide faster than clean water will.

• The breakdown can be measured by the oxygen produced.

Analysing your results

• Draw a graph of your results.• What are your conclusions from your

results?• Why is it better to use capillary

tubing in this experiment rather than normal glass tubing?

Prep Task

• How can we tell how polluted the environment is?– Read through the task on pages 22 &23

in the textbook

• Write a report of the pollution of the stream and its likely causes.

Learning Outcomes

• investigate how lichens can be used as indicators of air pollution

Lichens and Air pollution

• Lichens are used are indicators of air pollution

• Different lichens have different sensitivities to sulphur dioxide in the air.

Lichen

Plants can also be good indicators of pollution. Lichen are very sensitive to sulphur dioxide in the air. They do not grow well in areas with air pollution.

Lichen growing on a tree in a clean air area.

Trees with lichen

Trees without lichen

Click the trees to change their colour to show the polluted areas

Learning Outcomes

• Understand that mathematical modelling can be used to analyse and predict effects.

Modelling

• Mathematical modelling can be used to predict and analyse the effects of pollutants in the environment.

Learning Outcomes

• Discuss and understand that the effects of pesticides, such as DDT, became apparent in the early 1960s and the initial observation, accumulation and interpretation of scientific evidence emphasised the need to monitor the effects and control the use of these chemicals

Learning Outcomes

• explore information about the heavy metals which may be present in industrial waste and the types of pesticides used on crops. Some of these chemicals enter the food chain, accumulate in animal bodies and may reach a toxic level and so have harmful effects.

Chemicals and food chains

• Heavy metals and pesticides are two types of chemical that can enter the food chain.

• Heavy metal pollution includes lead and mercury

Minemata Bay

• Mercury released into the bay from a factory

• Phytoplankton absorb mercury from the water

• Zooplankton eat the phytoplankton• Fish eat the phytoplankton and the

zooplankton• Mercury builds up to high levels in the

fish making them poisonous• Humans ate the fish