Science Interactive LTD Copyright 2005
Science Interactive LTD
Science base multimedia CD-ROM for PC is a collection of 38 units or tools totalling over 1150
PowerPoint slides. Each unit covers a wide range of different delivery and learning styles, offering an
exciting way to involve your pupils during lessons or revision sessions. All styles of teaching and
learning are supported through use of high quality images, graphics, challenging exercises and
questions. Units can be used in the classroom via an interactive whiteboard, data projector or used
during individual study via a PC or school network.
Science Interactive LTD. PO BOX 50764 LONDON NW6 9AT email: sales@science-interactive.co.uk
web: www:science-interactive.co.uk
Unit 1: The Digestive System
Unit 20: Crude Oil and its Products
Unit 2: The Circulatory System
Unit 21: Rock Cycle
Unit 3: Healthy Body and Immunity
Unit 22: Elements, Molecules and Compounds
Unit 4: The Respiratory System
Unit 23: Ionic and Covalent Compounds
Unit 5: Nervous System and the Senses
Unit 24: The Halogens, their Uses and Compounds
Unit 6: Human Homeostasis
Unit 25: The Noble Gases, their Properties and Uses
Unit 7: Hormones and the Endocrine System
Unit 26: Rates of Reaction
Unit 8: Drugs and Bad Body Maintenance
Unit 27: Energy
Unit 9: Photosynthesis in Green Plants
Unit 28: Generating Electricity and its Domestic Use
Unit 10: Water Transport in Plants
Unit 29: Electricity
Unit 11: Flow of Energy and Elements through the Environment
Unit 30: Light and the Electromagnetic Spectrum
Unit 12: Mitosis and Meiosis
Unit 31: Radioactivity
Unit 13: Inheritance and Selection
Unit 32: Newton's Forces and the Effects of Forces
Unit 14: Evolution and Human Impact
Unit 33: Earth and Space
Unit 15: Genetic Engineering
Unit 34: The Earth and Plate Tectonics
Unit 16: The Periodic Table and its Elements
Unit 35: The Alkaline Earth Metals
Unit 17: The Alkali Metals
Unit 36: Sound and Hearing
Unit 18: Metals and their Properties
Unit 37: Natural Forces
Unit 19: The Transitional Metals
Unit 38: Cells, Tissue, Organs and Organs systems
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Nutrients
1
50,000kJ
2
3

Unit 11

Flow of Energy and Elements through the Environment
Unit 11: Flow of Energy and Elements through the Environment
Understand:
That producers are green plants, able to
manufacture glucose using sunlight, water and
carbon dioxide.
2.
That a simple food chain describes the
relationship between producers, consumers
and top predators.
3.
That a food web describes the feeding
relationship of many organisms within a
habitat.
4.
The energy flow through a food chain or web.
5.
That energy is lost between each trophic level.
6.
How energy is lost through each trophic level.
7.
That toxic chemicals like DDT can be bioaccumulated through a food chain.
8.
That elements like carbon and nitrogen are
recycled in the biosphere.
9.
Some of the effects of disrupting the carbon
cycle.
10. The main likely consequences of global
warming.
1.
Science Interactive LTD Copyright 2005
Keywords:
Producers, Consumers, Plants, Predators,
Photosynthesis, Food chain, Food web,
Biomass,
Energy,
Flow,
Feeding,
Relationship, Kilojoules, Tropic, Level,
Elements, Carbon, Greenhouse, Effect, Fossil
fuels, Nitrogen, Recycled, Biosphere, Global
& Warming.
Click mouse to begin
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web: www.science-interactive.co.uk
email: sales@science-interactive.co.uk
Science Interactive LTD Copyright 2005
Producers plants one
Plants are called producers because they produce all the World’s biomass via a process called
photosynthesis. Plants use energy from the s______ to combine carbon dioxide and w________
to form g__________ and oxygen. This reaction produces millions of tonnes of living matter,
that nourishes all other living organisms in the animal kingdom. The oxygen that plants release
into the atmosphere is used during cellular r_____________ by all living organisms. How can
we determine the biomass of a plant ?
Plants as producers:
Word bank: sun water glucose respiration
Photosynthesis in action
Plant yield
Plant yield: (kg per hectare)
Diagram
C6H12O6
6H2O
Chloroplast
Energy
Glucose
14000
6CO2
6O2
10000
6000
2000
Plant cells
Notes
Green chlorophyll contained in
palisade chloroplasts are able to
use light energy to enable carbon
dioxide and water to combine to
form glucose and oxygen.
<1000
Plants only use a small fraction of the sunlight energy, they
receive every year. Despite this, sugarcane produces up to
200 tonnes of glucose per year per hectare. The most
productive areas are the equatorial regions that receive the
most sunlight energy.
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Producers plants two
Plants produce all the nutrients (proteins, carbohydrates and lipids) that supply the World’s
f_____ chains. This includes the dietary nutrients that directly (through plant produce) or
indirectly (through consumers) supply the human population. Plants use light energy to
combine w_______ and carbon dioxide to form glucose and oxygen. Glucose is a store of
chemical energy and is used for cellular respiration by the plant or used to manufacture its
lipids, carbohydrates and proteins.
Energy changes during photosynthesis:
Word bank: food water
Photosynthesis in green plants
Key
6O2
C6H12O6
H2O
6H2O 6CO2
Products
Potential energy
Activation energy
Substrates
Progress of reaction
C6H12O6
Net energy taken
in during reaction
O2
CO2
In this reaction H2O
and CO2 substrates
are combined in the
plant leaf cells using
light
energy
to
produce
glucose
(C6H12O6) and O2.
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Producers plants three
The glucose produced during photosynthesis in green plants is used to make plant
c____________, lipids and proteins. Every year over 70,000,000 kJ of sunlight energy falls
on every metre squared of land. Plants only use about 90,000 kJ/m2/year of light energy
during photosynthesis, however they produce over 130 billion tonnes per annum of
biomass, globally. Overall plants y______ depends on a number of factors including light
availability, soil quality, rainfall levels and competition. How could you determine the
yields of different crops over time ?
Plant yield and biomass:
Crop
Word bank: carbohydrates yield
Sugarcane
Corn
Rice
Wheat
Sugarcane,
rich
in
glucose can produce a
yield of up to 9000 kg
per acre.
Corn, rich in proteins
and carbohydrates can
produce a yield of up to
5500 kg per acre.
Rice, rich in carbohydrates can produce a
yield of up to 3000 kg
per acre
Wheat, rich in carbohydrates and sugars can
produce a yield of up to
2500 kg per acre.
Diagram
Notes
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Producers plants four
Plants are extremely efficient at transforming the e________ carried by light to chemical
energy trapped in glucose molecules, which are produced during photosynthesis. Their
efficiency is about 80%, far higher than typical values for h__________ and carnivores.
Only a small fraction of the chemical energy they produce in the form of glucose is lost
through respiration or waste. How could you determine the amount of glucose that is used
during cellular respiration in plants ?
Plants using light energy:
Word bank: energy herbivores
Plants use of light energy
Diagram
Light energy
10,000 kJ
1
Process
Biomass: Energy contained in
8,000 kJ 1 the tissues of the plant
(available for the next level)
Respiration: Energy used in
1,500 kJ 2 cellular respiration by all
plant cells.
2
3
Notes
500 kJ
Waste: Energy contained in
3 the waste materials found in
leaves.
The transfer of energy from the sun’s rays to the glucose
found in plant leaves is achieved during photosynthesis.
Plants are highly adapted and efficient at transforming light
energy to chemical energy. Over 132 billions tonnes of plant
biomass is produced globally every year.
Only a very small fraction of
energy is used for respiration
or lost as waste. Plants are
almost 80% efficient as
producers.
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Primary consumers herbivores
Primary consumers or h___________ ingest, digest and assimilate plant nutrients
produced as a result of photosynthesis. Herbivores are the most efficient animals, able to
survive only by feeding on nutrients from plants. Herbivores provide a rich protein source
for secondary and tertiary consumers. They are highly adapted to d_______ and
breakdown the cellulose found in the cell wall of plant cells. Most carnivores including
humans are unable to digest this plant polymer. Plant cellulose is known as what in the
human diet...it is one of the seven essential food groups ?
Primary consumers:
Herbivore
Word bank: herbivores digest
Tree cutter ants
Caterpillars
Rabbits
Buffalo
Tree cutter ants can
carry and consume
many times their
own body weight of
plant material such
as leaves.
Caterpillars search for
and consume plant
leaves rich in sugary
sap to absorb and
assimilate in their
own bodies.
Rabbits feed on
grass and other small
shrubs. Their success
is because of their
high
reproductive
rate.
Buffalo graze almost
exclusively on grass,
turning this simple
nutrient source into
valuable animal flesh
rich in proteins.
Diagram
Notes
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Secondary consumers carnivores
Secondary consumers or c____________ ingest, digest and assimilate the nutrients
found in herbivore bodies. They, like tertiary carnivores or top p____________ rely
on the rich content of p_________ found in the flesh or muscle tissue of herbivores.
Like all animals and plants, they are highly adapted to catch and kill their prey. The
spider for example produces a highly complex web to catch insects. Spider silk is
stronger than steel weight for weight. It also injects its prey with a toxin that causes
paralysis.
Secondary consumers:
Carnivore
Word bank: carnivores predators protein
Ladybird
Snakes
Frogs
Spiders
Ladybirds feed on
aphids which are
found on many plants.
They are natures own
pesticides.
Snakes feeds on
small animals and
paralyse their prey
before its digestion
with venom.
The Brazilian tree
frog feeds on small
insects or mammals,
by catching them on
their ‘sticky tongue.’
Spiders spin webs to
catch small insects
and
like
snakes
paralyse their prey
with venom.
Diagram
Notes
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Primary and secondary consumers
Primary consumers ingest, d______ and assimilate the nutrients found in plants. Secondary
consumers rely on the nutrients provided by eating the bodies of herbivores. Both primary and
secondary consumers are inefficient at turning what they consume into tissue biomass which is
then available for the next trophic level. This is because a large part of the nutrients they
consume is used in c___________ respiration to provide the energy for movement, cellular
respiration, keeping warm, growth and repair. Their average efficiency is only about 20%
compared to plants which are about 80% efficient.
Primary and secondary consumers:
Word bank: digest cellular
Energy efficiency of consumers
Diagram
Nutrients
10,000 kJ
1
2
3
Notes
Process
Biomass: Energy contained in
2000 kJ 1 the tissues of the consumer
(available for the next level)
Respiration: Energy used in
6000 kJ 2 cellular respiration by all
tissues and cells.
Waste: Energy contained in
2000 kJ 3 the waste materials excreted
by consumers.
The transfer of energy from plant tissue through the bodies of
herbivores to the next feeding level i.e; secondary consumers
is relatively inefficient. This is because a large part of the
nutrients they consume is used in cellular respiration to
provide the energy for movement, keeping warm and repair.
Only a very small fraction of
energy is turned into biomass
for the next feeding level.
Consumers are about 20%
efficient.
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Unusual carnivores
Even in the plant kingdom, we can find some examples of plants that cannot produce
sufficient nutrient by p_____________ alone. They rely on trapping and digesting the
nutrients of small insects and sometimes animals. The Venus fly trap lives in very
poor soil and supplements its nutrient requirements by trapping and digesting small
insects. The fly is attracted to the brightly coloured petal which resembles animal
flesh. The leaves close and enzymes begin to d_______ the insects’ body.
Carnivorous plants:
Plant
Word bank: photosynthesis digest
Venus fly trap
Heliamphora
Sundew plant
The venus fly trap, the best
known carnivorous plant
closes shut on its prey. It is
then able to digest, and
absorb the nutrients using
enzymes.
The Heliamphora attracts
small insects like flies by
producing a smell like rotting
meat. In the flower, a sticky
fluid which contains enzymes
digests its prey.
The sundew has hundred of
tiny hair-like protrusions
which catch very small
insects. Like many other
carnivorous plants, they habit
nutrient poor areas.
Diagram
Notes
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Top predators carnivores one
Top predators like lions, wolves, killer whales and brown bears are located at the top of the
food chain or web and have no natural p____________. They are usually highly evolved
to catch and kill their prey, equipped with speed, strength, forward facing v__________,
good hearing and canine t_________. Successful top predators have a very varied diet
relying on many different animals for their proteins, lipids and carbohydrates. Name three
other top predators and their adaptations ?
Top predators:
Predator
Word bank: predator vision teeth
Tiger
Wolf
Killer whale
Brown bear
Tigers and other big
cats
are
highly
adapted to stalk,
chase and kill their
protein rich prey.
Artic wolves and wild
dogs hunt in large
packs to increase their
success when they
hunt their prey.
The killer whale is
able to catch and kill
prey like dolphins
and seals in a marine
environment.
The brown bear hear
in this picture is
taking advantage of
salmon returning to
spawn.
Diagram
Notes
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Top predators carnivores two
Tertiary consumers or top predators ingest, digest and assimilate the nutrients found in the
bodies of herbivores or secondary consumers. Top predators are the least efficient at turning
what they consume into tissue biomass which is then available to the next trophic l_______
...decomposers. In this case, to decomposers which will then recycle some of the nutrients
trapped in the dead bodies of top predators back into the soil. This is because a large part of the
nutrients they consume are used in cellular respiration to provide the e_________ for
movement, keeping warm and repair. Their average efficiency is only about 15%.
Top predators:
Word bank: level energy
Energy efficiency of predators
Diagram
Nutrients
10,000 kJ
1
2
3
Notes
Process
Biomass: Energy contained in
1500 kJ 1 the tissues of the consumer
(available for decomposers)
Respiration: Energy used in
6500 kJ 2 cellular respiration by all
tissues and cells.
Waste: Energy contained in
2000 kJ 3 the waste materials excreted
by consumers.
The transfer of energy from the bodies of top predators to the
next trophic level (decomposers) top predators is very
inefficient. This is because a large part of the nutrients they
consume is used in cellular respiration to provide the energy
for movement, keeping warm and repair.
Only a very small fraction of
energy is turned into biomass
for the next feeding level.
Top predators are about 15%
efficient.
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Decomposers
Decomposers including b__________ and fungi play a vital role in the recycling of
nutrients trapped in the bodies of primary and secondary consumers. Bacteria help break
down proteins carbohydrates and l_________ in all organisms producing simple soluble
molecules that can be reused by plants. These molecules are taken from the soil by the
plant root system using active transport. Without this recycling of nutrients, plant growth
would be severely affected. Why is the soil in graveyards always rich in nutrients ?
Decomposers:
Decomposers
Word bank: bacteria lipids
Bacteria
Fungi
Moulds
Sewage and waste
Bacteria cells exist
everywhere and it is
estimated that their
total cell biomass
exceeds that of all
other species.
Fungi grow and
breakdown mainly
dead plant materials
releasing nutrients
back into the food
chain.
Moulds also play a
large role in recycling
small molecules and
nutrients
making
them available to
plants.
Sewage
including
animal waste is rich
in nutrients including
nitrogen. It is usually
spread over the land
like many fertilisers.
Diagram
Notes
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Food chains one
Food chains shows us what eats what in a particular habitat. They show the flow of
nutrients or food energy from producers through p_________, secondary and tertiary
consumers. Food chains always begin with a producer, usually a green plant and end
with a top predator. In the following food chains, what would happen to the number
of secondary consumers and producers if the primary consumers died (slugs and
caterpillars)
Food chains:
One
Word bank: primary
Oak leaves
Slug
Robin
Sparrow hawk
Oak leaves
Caterpillar
Hedgehog
Fox
Diagram
Two
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Food chains two
There are many food chains and webs found in marine environments. Within marine
environments about 90 billion tonnes of biomass are produced each year. This is not
surprising, since the oceans and seas receive over 70% of the s_______ energy from the
sun. Humans only take 0.02 billions tonnes per annum out of marine ecosystem, which
remain an untapped resource. Find out how low levels of crude oil in the sea can
dramatically affect marine food chains ?
Marine food chain:
Word bank: sun’s
Plankton
Krill
Crabeater seal
Killer whale
Plankton use light
energy, CO2 and
water producing part
of the 90 billion
tonnes of marine
biomass per year.
Krill filter and trap
small plankton. They
provide a rich protein
source for secondary
consumers like seals
and the blue whale.
Crabeater seals feed
predominately
on
krill and other fish.
They assimilate the
krill proteins into
their bodies.
The killer whale, is a
supremely adapted
marine
organism
which feeds mainly
on crabeater seals
and dolphins.
Diagram
Notes
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Food webs one
In most habitats, primary, secondary consumers and top predators feed on more than
one species of plant or animal. Furthermore, if two species relies on only one food
source this will increase c_____________ among species. A food web is made up of
many food chains and gives a more complete picture of how herbivores and
carnivores feed. Look at the woodland food web, find all six separate food chains ?
Woodland food web:
Producers
Word bank: competition
Herbivores
Carnivores
Top predators
Mouse
Owl
Oak leaves
Earthworm
Weasel
Snail
Hedgehog
Grass
Rabbit
Fox
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Food webs Two
Marine habitats are home to many different feeding relationships, which can also be
shown by a food web. In the great o________, nutrients from the seabed are
constantly being brought to the surface by ocean currents. Colder oceans are more
productive because of their stronger currents. Look at the marine food web, find all
five separate food chains ?
Marine food web:
Producers
Word bank: oceans
Herbivores
Carnivores
Top predators
Barnacle
Seabird
Algae
Periwinkle
Dog whelk
Limpet
Starfish
Seaweed
Mussel
Crab
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Biomass through food chains
Using biomass instead of numbers of organisms gives the actual mass of living things at each trophic
level. It demonstrates how available b_________ for the next levels is lost through supplying energy
for activities like respiration, body heat, movement and reproduction. Some is also lost as indigestible
nutrients and w______. Interestingly, of the 130 billion tonnes of World’s plant biomass, only 0.2
billions tonnes enters the human food chain as animal protein like beef, chicken and lamb.
Biomass through food chains:
30 kg Biomass
4.5 kg
Biomass
Waste
Biomass
Waste
200 kg
Top predator
Respiration
Respiration
Biomass
Waste
Waste
1000 kg
Carnivores
Respiration
Herbivores
Respiration
Producers
Word bank: biomass waste
Eagle
Snake
Grasshopper
Grass
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Energy loss through trophic levels
Losses of energy occur at all trophic levels. Most herbivores only achieve about 20%
efficiency. That means for every 1000 kJ of nutrients consumed, only 200 kJ of energy
is available to the next trophic level. Most of the energy is used for c__________
respiration, body warmth, movement or remains in undigested food as faeces. Most
carnivores can only achieve about 15% efficiency. Why do vegetarians have less
impact on the environment ?
Energy loss through trophic levels:
Word bank: cellular
Energy use and loss in animals
Diagram
Nutrients
1
50,000 kJ
2
3
Notes
Process
Faeces: Energy contained in
20,000 kJ 1 the faeces and undigested
food of the animal.
Respiration: Energy used in
20,000 kJ 2 cellular respiration and for
body heat.
Biomass: Energy contained
10,000 kJ 3 in the tissues of the animal
(available for the next level)
The transfer of nutrients from producers to primary and
secondary consumers involves ‘wastage.’ The daily nutrient
requirement in kilojoules for a horse is around 50,000 kJ with
only 10,000 kJ of nutrients ending up as part of the horse’s
body.
Just under half the energy
(20,000 kJ) passes undigested
through the horse's body,
with 20,000 kJ used during
cellular respiration.
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Pyramids of numbers
Pyramids of numbers allows us to show the number of individuals within a species at each
t________ level. In most pyramids of numbers, the number of organisms decreases as you
ascend the trophic levels because of two things: Usually the mass of the organism
increases and energy is lost between each level.
Pyramid one: The pyramid of numbers shows that 10,000 grass feeds 800 snails which then feed 33 weasels which then 5
foxes.
Pyramid two: The pyramid of numbers shows that 1 oak tree feeds 800 snails which then feed 24 hedgehogs which then 7
owls.
Pyramids of numbers:
Pyramids of energy one & two
One
Food chain
Two
5
Owl
7
Weasel
33
Weasels
24
Hedgehog
Hedge
hog
Snail
Snail
800
Snails
Grass
Species
Owl
Fox
Food chain
Fox
Species
Word bank: trophic
10,000
Grass
800
Snails
1 Oak tree
Oak
tree
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Pyramids of energy one
The most accurate method of showing how nutrients are transferred from producers to
top predators and the feeding relationships between o___________ is to use an energy
pyramid. These energy pyramids show the amount of energy transferred from one
level to the next. The energy available to the next level is through growth. Energy is
always l_____, as you ascend from one level to the next. Unlike pyramids of
numbers, pyramids of energy can never be inverted.
Pyramids of energy:
Species
Fox
Food chain
Word bank: organisms lost
Pyramids of energy
Notes
104 kJ/m2/yr
Fox
Weasel
2,300 kJ/m2/yr
Weasels
Snail
12,500 kJ/m2/yr
Snails
Grass
90,000 kJ/m2/yr
Grass
The pyramid of
energy shows that
90,000 kJ/m2/yr is
pass to the snail
from the grass. The
snails pass 12,500
kJ/m2/yr
to
the
weasels which then
passes 2,300kJ/m2/yr
to the top predator,
the fox. How is this
energy lost through
the food chain ?
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Pyramids of energy two
Understanding how energy is lost at each trophic level is important. Some of the
energy from ingested food is lost through c_________ respiration and body heat.
Some food molecules are not digested, passing through as waste. The further you
move up the food chain or w____, less of the original energy found in producers is
passed along. Look at the following food chain and pyramid of energy and work out
the energy lost at each trophic level. Explain how the energy is lost ?
Pyramids of energy:
Species
Pyramids of energy
1,230 kJ/m2/yr
Starfish
Starfish
8,900 kJ/m2/yr
Mussels
Mussels
67,500 kJ/m2/yr
Algae
Notes:
Crab
Crab
Food chain
Word bank: cellular web
345,000 kJ/m2/yr
Algae
The pyramid of
energy shows that
345,000kJ/m2/yr is
passed to the
_________kJ ?
mussels from sea
algae. The sea
mussels then pass
67,500kJ/m2/yr to
________kJ ?
the starfish which
then
pass
2
8,900kJ/m /yr to
the top predator,
the crab. Work out
_______kJ ?
how much energy
is lost at each
level. How is this
energy lost ?
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Pesticides and toxic chemicals in food chains
Pesticides, heavy metals like m__________ and other chemicals that are not broken
down, can enter a producers or consumer’s body and then pass along the food chain.
DDT is a chemical sprayed on crops to control insects and in some parts the malaria
spreading m___________. In the USA, DDT found in ponds and lakes, was taken up
by plant plankton and then accumulated in consumers further up the food chain. The
levels of DDT increased from primary consumer (fish) to top predator (grebe),
reaching lethal levels. This is called bioaccumulation.
Bioaccumulation of toxins in food chains:
Species
Food chain
Word bank: mercury mosquito
Bioaccumulation
DDT ppm
Grebe
2000 ppm
Grebe
Fish
Plankton
Fish
Fish
300 ppm
Plankton
8 ppm
Water
0.3 ppm
Water
Notes
During bioaccumulation
of pesticides and other
chemicals, small levels
present in the water or
producers accumulate in
the bodies of primary and
secondary
consumers.
This is because DDT is
not easily broken down.
The grebe also eats many
fish, for each one it eats it
receives a dose of DDT.
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Predator prey cycles one
Predators like ladybirds trap, kill and feed on their prey. The greater the number of
predators, the larger the effect they have on prey numbers. The number of available
prey also has an effect on the number of p__________. If for example, prey numbers
reduce because of disease or lack of plant growth, the number of predators will be
reduced. The effect on predator numbers is usually delayed. Remember: numbers are
increased in predators by reproduction and reduced by starvation and death.
Ladybirds and aphids:
Species
Ladybird
Aphids
Rose bush
Food chain
Word bank: predators
Ladybirds and aphids
Notes
Numbers of prey and
predators are closely
linked. A reduction in
the food supply will
cause a decrease in
the
number
of
predators. However,
this reduction is
slightly delayed.
Explain what causes
this delay and why
does the weather
affect the predator –
prey cycle ?
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Predator prey cycles two
Another predator prey relationship is the snowshoe hare and the lynx. The lynx has to trap, kill
and feed on their prey. The greater the n________ of predators, the larger the effect they have
on prey numbers. The number of available prey also has an effect on the number of predators,
although this effect on predator numbers is usually delayed. In this relationship decades with
very hard winters and low plant growth caused a subsequent d__________ in snowshoe hares
and then some months later, the total numbers of lynx also decreases. Explain why over the last
100 years there is also a general slow decline in both the number of lynx and hares ?
Lynx and the snowshoe hare:
Lynx and snowshoe hares
Lynx
Notes
Snowshoe hare
Lynx
120
10
Thousands of hares
80
5
40
normal
37oC
0
0 1850
0
2
1875
4
1900 8
Yea
6 time days
r
1925
10
Thousands of lynx
Predator prey cycle
Snowshoe Hare
Word bank: number decrease
Numbers of prey
and predators are
closely linked. A
reduction in the food
supply will cause a
decrease in the
number of predators.
However,
this
reduction is slightly
delayed.
Explain what causes
this delay and why
does the weather
affect the predator –
prey cycle ?
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Element cycles
Decomposers including b__________ and fungi play a vital role in the recycling of
nutrients trapped in the bodies of primary and secondary consumers. Microbes help
break down proteins, carbohydrates and l_________ in all organisms producing
simple soluble molecules that can be reused by plants. These molecules are rich in
two very important elements: Carbon and nitrogen.
Recycling nutrients:
Word bank: bacteria lipids
Carbon
Nitrogen
Recycling
Fungi
Diagram
Bacteria
+
Carbon
C
Notes
12
6
Plants and animals are all
built using carbon chains
found in cellular proteins,
carbohydrates, sugars and
lipids.
Nitrogen
N
14
7
Nitrogen is essential for
protein manufacture by
plant and animal cells. It
is found in all amino
acids.
All life in the biosphere relies on the
recycling of nutrient molecules by
decomposers including bacteria and
fungi. Without recycling ‘life on
Earth’ would fail.
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The nitrogen cycle
All living organisms require the element n_________ to make proteins. Although air contains
almost 80% nitrogen gas, plants and animals cannot use it in this form. Nitrogen (N2) has to be
changed to nitrates (NO3-) before plants can absorb and use nitrogen to build proteins. Animals
acquire their nitrogen from plants or animals that feed on plants. The nitrogen cycle shows how
nitrogen gas is changed into nitrates.
The nitrogen cycle:
Word bank: nitrogen
Lightning
Atmosphere
N2 Atmosphere
The atmosphere is 78% Nitrogen gas.
Animal waste
Animal biomass
Plant biomass
Legumes
Fertilisers
Soil
Denitrifying
bacteria in soil
(NH3)
Plant and
animal remains
(NH3)
Nitrogen fixing Nitrates from
bacteria in root fertilisers &
nodules
lightning
Nitrates (NO3-)
in the soil.
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Factors affecting the nitrogen cycle
Intensive farming year after year, reduces the quality of the soil, stripping all the essential plant
minerals like n__________. Farmers add fertilisers at the beginning of every growing season to
replace these lost minerals. Crop yield increases as the amount of fertilisers is added to the soil.
Nitrates that are washed out and end up in lakes and rivers can pollute our drinking water and
cause algae to grow using all the available o_________ in the water. Low oxygen levels can
kill fish and freshwater invertebrates. How will this affect freshwater food chains ?
Factors affecting the nitrogen cycle:
Word bank: nitrogen oxygen
Fertilisers
Lightning
Animal waste
Nitrogen fixing bacteria
The use of nitrate
fertilisers
benefits
modern farming by
improving crop yields.
Too much can lead to
the destruction of many
freshwater habitats.
During a lightning strike
nitrogen in the air is
converted to nitrates
which can then dissolve
into the soil. This is
nature’s own way of
fertilising the soil.
Organic farmers only
use natural sources of
fertilisers like animal
waste or manure. They
do not use artificial
fertilisers
made
by
companies like ICI.
Nitrogen fixing bacteria
are found in root nodules
of plants like peas. The
bacteria convert N2 from
the air directly into
nitrates (NO3-), a form of
nitrogen, plants can use.
Diagram
Notes
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The carbon cycle
All living organisms require the element c_________ to make carbohydrates, proteins and other
important molecules which make up living organisms. Cellular respiration and decomposition
by bacteria release carbon dioxide into the atmosphere. Plants use this during p_____________
at the same rate. The amount of CO2 in the atmosphere should stay the same but it is increasing
rapidly because of the use of fossil fuels and deforestation.
The carbon cycle:
Word bank: carbon photosynthesis
Atmosphere
Respiration
CO2 Atmosphere
There is 750 billion tonnes of CO2 trapped in the
atmosphere. This is rising by 3 billion tonnes a
year because of fossil fuel use and deforestation.
Fossil fuel combustion
Land deforestation
Photosynthesis
Plant biomass
Soil
Buried fossil fuels
Ocean
Marine biomass
There is 3300 billion tonnes of carbon trapped in oil, coal There is 1020 billion tonnes of carbon trapped in living
and natural gas deposits found under rock sediments.
organisms like algae. CO2 is also dissolved in the oceans.
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Causing the greenhouse effect
Our atmosphere is changing and will continue to change for many years to come. The
average concentration of carbon dioxide in the air is increasing because of human
activities. Fossil fuels rich in c________ are extracted deep underground and
combusted with o__________ forming over 3 billions tonnes of carbon dioxide per
year. We are also destroying large areas of ancient forests in Africa and South
America. Why does this affect carbon dioxide concentrations in the atmosphere ?
Factors affecting atmospheric carbon concentrations:
Word bank: carbon oxygen
Fossil fuels
Deforestation
Combustion engine
Renewable energy
Combusting fossil
fuels like petrol, gas
and diesel release
over 3 billion tonnes
of carbon dioxide
every year.
The destruction of
the rain forests adds
to the carbon dioxide
in the atmosphere
and also increases the
erosion of soil.
Over 500 million cars
are responsible for the
release of carbon
dioxide found in the
atmosphere. Is public
transport the answer ?
Using
renewable
forms of energy
liked wind power
could reduce carbon
levels and slow the
greenhouse effect.
Diagram
Notes
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The greenhouse effect
Our planet Earth, is surrounded by an atmosphere, which is a collection of gases including
nitrogen, oxygen, water vapour and carbon dioxide. Insulating molecules like carbon dioxide
are called greenhouse gases allowing s______ energy to pass through whilst absorbing some of
the h______ energy radiating back into space. Correct levels of atmospheric carbon dioxide
keeps temperatures ambient. The combustion of fossil fuels and subsequent increases in
atmospheric carbon dioxide has caused too much heat energy to be absorbed. The atmosphere
is becoming warmer. How can we reduce carbon dioxide concentrations in the atmosphere ?
The greenhouse effect:
Word bank: solar heat
The greenhouse effect
Polar ice caps
More deserts
Rising oceans
Diagram
Absorbed in atmosphere
by greenhouse gases
15
15
50
50
Altitude (km)
Notes
The Earth has warmed by 3oC over
the last century and is predicted to
warm by 4oC over the next 50
years. This is because of increases
in CO2. How can we stop this ?
The polar ice caps are melting, reflecting less heat energy back
to space and causing rising sea levels. Arid land found in
Africa and the Middle East will become deserts in the near
future. Rising seas and oceans will engulf low lying countries
like Holland and Bangladesh.
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Effects of global warming one
Scientists have many theories as to what may happen over the next century because of rising
carbon dioxide levels in the a__________, as a result of combusting fossil fossils and the
subsequent rising global temperatures. There is now increasing agreement amongst scientists
that atmospheric carbon dioxide levels need to be controlled. Many countries have signed ‘The
Kyoto Agreement’ which aims to reduce carbon emissions over the next 20 years. This will
perhaps s____ global warming. Only one country, America has not signed up, she is the biggest
carbon polluter. Why do you think that America has not signed up ?
Effects of global warming:
Word bank: atmosphere slow
Global warming
Drought
Ozone layer
Flooding
Average
world or
global temperatures are
set to increase by
between 0.5 and 1oC
per decade for the next
fifty years.
More
extremes
of
temperatures are now
expected with lower
rainfall in areas which
already see little rain
over the year.
The destruction of the
Ozone by CFCs from
aerosols will also add to
global
warming
by
reflecting less infra red
heat given out by the sun.
Flooding will increase
over the next decade. In
England (summer 2004),
we had some of the worst
flash floods on record,
including Boscastle.
Diagram
Notes
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Effects of global warming two
The greenhouse effect is a natural process where the 750 billions tonnes of c________
dioxide in the atmosphere maintains the Earth’s atmosphere at hospitable temperatures,
which are supportive of life, here on Earth. Combusting fossil fuels is adding to this
‘warming effect’ causing average global t___________ to rise over the last fifty years.
Global warming will continue, whilst we continue to combust fossil fuels like coal and oil.
The World’s weather, habitats and temperature are set to change over the next century.
Effects of global warming:
Word bank: carbon temperatures
Weather
Waves
Biodiversity
Melting ice caps
The World’s weather
will
become
more
dynamic. In summer
2004,
Florida
in
America was hit by
three hurricanes causing
immense damage.
Damage due to strong
tides and wave action
along the coast will
also increase over the
next decade. Parts of
the England's coastline
are now being eroded.
Animals and plants may
undergo mass extinction
in the next one hundred
years if global warming
continues. The Malarial
Mosquito is spreading
north into Europe.
The ice caps have shrunk
in size over the last 30
years. This may rise sea
levels and also reduce the
amount of the Sun’s infra
red heat reflected back
into space.
Diagram
Notes
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Extension questions and homework
1:
Define the following terms: Producers, Consumers, Top-predators, Food-web, Biomass, Energy-flow, Trophiclevel, Greenhouse-effect & Biosphere
2:
3:
4:
.
Look at the diagram of the three types of organisms. Complete the table:
Organism
Class
How are they adapted for their role
Other examples
Killer Whale
_____________ ?
__________________________ ?
Camel
Primary consumer
Rabbit, buffalo, sheep, Slug, Snail & ants
Bacteria
_____________ ?
___________________________ ?
Match the following organisms with their habitats:
Frog
Heather
Crab
Squirrel
Killer whale
Trout
Wall
Rocky shore
Ocean
River
Wood
Pond
Complete:
Producers like green plants are able to make their own ______________ by photosynthesis. These producers are
fed upon by herbivores or ____________ consumers. These provide food for ______________ consumers: Dead
and _____________ material provide nutrients for ______________ and fungi. These feeding relationships can be
shown in a food chain or __________.
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Look at the information in the table below. It shows the relationship between the numbers of lynx and snowshoe
hairs over the last 150 years:
a) Explain the relationship between the numbers of lynx
Thousands of hares
120
Snowshoe hare
Lynx
10
80
6:
5
40
normal
37oC
0
0 1850
2
18754
1900
Year 6 time
days 8
0
1925
10
Thousands of lynx
5:
and snowshoe hares over the last 150 years.
b) Why is there a delay in the response of lynx numbers
to declining numbers of snowshoe hares..
c) Name two other prey – predator relationships.
Look at the food chain below and answer the questions:
a) Name the producer.
Eagle
10 kJ
b) Name the secondary consumer.
c) Name the top predator.
Fox
7:
100 kJ
Rabbit
1,000 kJ
Grass
10,000 kJ
d) Explain how energy is loss through each feeding level.
e) Draw a food chain with five links in it.
a) Give 2 ways in which nitrogen in the form of nitrates can be added to the soil.
b) How is nitrogen in the form of nitrates lost from the soil and what do plants use nitrates for during normal
growth and development.
c) What are the main effects of the greenhouse effect and how can we reduce its impact on global weather.
Internet:
Go to google.co.uk and find about the greenhouse effect. Also find out about how you can reduce you impact on
the environment by using less fossil fuels.