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Ecology is the study of the interactions between living
things and between organisms and their environment.
Their environment refers to all the conditions in which the
organism lives, which affect the growth and development
of the organism.
What is the Biosphere?
The biosphere is that part of the earth
inhabited by living organisms, including land,
ocean and the atmosphere in which life can
exist.
Biosphere
What is an Ecosystem?
An ecosystem is a community of living organisms
interacting with one another and their non-living
environment within a particular area.
Ecosystem = Communities + Environment
Note: ecology is the study of ecosystems
Examples of ecosystems
Woodland
Hedgerow
Seashore
Marine
Grassland
Freshwater
Tree, etc.
Can you name some more?
To study an ecosystem
We divide the ecosystem into a number of smaller,
more manageable areas - habitats.
Habitat: area where an organism or group of organisms
live.
More Definitions
Population: all the members of the same species
living in an area e.g. a population of frogs in a pond.
Community: a group of plants and animals which
share resources of a particular habitat.
The resources they share would include:
water
shelter
space
light
food
Environmental factors that affect organisms
Abiotic
Biotic
Climatic
Edaphic
*Aquatic
Abiotic Factors
Abiotic are non-living factors
•Temperature
•Light intensity
•Air speed
•Water current
•Humidity
•pH
•Dissolved oxygen
•Salinity
•Nitrate, phosphate and other
plant nutrients
Abiotic factors in a woodland
Biotic factors
Biotic are living factors
•Plants for food and shelter
•Predators
•Prey
•Parasites and pathogens
•Decomposers
•Competitors
•Pollinators
Climatic factors
Climatic are the average weather conditions that affect
the community in an ecosystem.
•Temperature
•Rainfall
•Humidity
•Wind
•Light intensity (including
seasonal variations)
•Day length
Edaphic Factors
Edaphic factors: soil factors associated with:
•Soil type,
•Soil pH,
•Available (soil) water,
•Air and Mineral content,
•Humus,
•Soil texture and Structure.
Aquatic Environmental Factors
Aquatic environments have special factors that
influence them:
•Light penetration
•Currents
•Wave action
Energy Flow
Ecosystems are unable to function unless there is a
constant input of energy from an external source.
Where does this energy come from?
The Sun
The Sun
The sun is the primary source
of energy for our planet.
Energy Flow
Feeding allows energy to flow from one organism to
another in an ecosystem.
• All living things require energy, in order to live.
• Plants receive this energy from the sun, using this
solar energy and chlorophyll by a process of
photosynthesis they make their own food.
• Because they can make their own food (autotrophic)
plants are called producers
Energy Flow
• All other organisms in the ecosystem either
directly or indirectly obtain their energy from
green plants.
• Organisms that feed directly from green plants
are called primary consumers
Herbivores and decomposers are examples
of primary consumers
Energy Flow
• If the organisms feed on dead animal remains
they belong to secondary consumers (carnivores)
• The feeding relationship between organisms in
which energy is transferred is called a food chain.
• The food chain must always start with a primary
producer i.e. a plant
Energy Flow in an Ecosystem
Is the pathway of energy transfer from one organism to
the next in an ecosystem due to feeding, e.g. along a food
chain
Food Chain
Is a flow diagram that begins with a plant and shows how
food/energy is passed through a series of organisms in a
community.
Each organism feeds on the one before it.
A food chain ends when there is not enough energy to
support another organism.
An example of a food chain:
grass  rabbit  fox.
Woodland Food Chain
Honeysuckle  aphids  ladybirds  thrushes
Producer
Primary
consumer
Secondary
consumer
Tertiary
consumer
A Grazing food chain
• is a sequence of organisms in which each one is eaten
by the next member in the chain.
• the initial plant is living.
Grass  grasshoppers  frogs  hawks
Seaweed  winkles  crabs  herring gulls
Phytoplankton  zooplankton  copepod  herring
Grazing Food Chains
Trophic Level
The trophic level is the position of an organism in a
food chain.
At each trophic level about 90% of the received energy
is lost to the environment as a result of respiration and
only 10% of it is retained for the next level.
• Plants are at the 1st trophic level (T1)
• Herbivores occupy the 2nd trophic level (T2)
• Carnivores (eat herbivores) are at the 3rd trophic level
(T3).
• 4th trophic level (T4) is often occupied by the top
carnivore.
Trophic Level
Trophic Level
Organism
Plankton
Barnacle
Whelk
Crab
Trophic Level
1st
nd
2
rd
3
th
4
Food Chain
• The size of the animal increases as you go along the
chain – this is because each animal tends to feed on
something smaller than itself.
• The numbers of individuals at each level decreases –
there will be far more grass plants in a field than there
will be rabbits.
• The relationship between the number of individuals at
the different levels is usually represented as a pyramid
of numbers
Pyramid of Numbers
• A diagram that represents the numbers of organisms
at each trophic level in a food chain.
•Bottom layer is the largest and represents a very large
number of primary producers
• The next layer smaller and represents a smaller
number of primary consumers
•The next layer – the no. of secondary consumers
• The uppermost layer where there may be only one
tertiary consumer
Pyramid of Numbers
Pyramids of Numbers
Types of Pyramids:
• Normal
• Distorted
• Inverted
Distorted Pyramid of Numbers
Inverted Pyramid of Numbers
Food Web
This is a chart showing all the feeding connections in the
habitat/ecosystem.
Constructed by showing the links between all the
interconnecting food chains in the habitat.
Food Web
the interconnected food chains in an ecosystem e.g.
Seashore Food Web
Food Niche
A niche is the functional role of an organism in an
ecosystem.
A food niche refers to the feeding role of an organism in a
habitat.
Predators: are specialised to find and kill their prey e.g.
fox
Parasites: are specialised to feed in or on the host e.g.
liverfluke, fleas
Nutrient Recycling
There is a limited amount of nutrients on earth e.g. you
are probably aware of the water cycle – where water is
constantly being recycled in nature. There are similar
cycles for all nutrients.
When plants and animals die, their nutrient content is not
wasted.
Bacteria and fungi decompose the remains and release the
nutrients back into the abiotic environment (i.e. into the
soil, nearby water and air).
Nutrient Recycling
These nutrients are then taken up by other plants and
used to make new organic material.
This material is passed on down the food chains and is
reused by all the chain members.
When death occurs for these members, the nutrients are
again returned to the abiotic environment and the cycling
of nutrients continues in this circular way.
Recycling nutrients within an ecosystem
Nutrient Recycling
Nutrient recycling is the way in which elements are
continuously being broken down and/or exchanged for
reuse between the living and non-living components of an
ecosystem.
While many nutrients are recycled we will focus on two in
particular:
• Carbon
• Nitrogen
The Carbon Cycle
• The carbon cycle is the way in which carbon is taken
from and added back to the environment.
• Three groups of organisms are involved in the carbon
cycle:
1. Plants
2. Animals
3. Micro-organisms
The Carbon Cycle
Role of organisms in the carbon cycle:
1. Plants:
- remove carbon from the environment in
photosynthesis and return it in respiration.
2. Animals:
- obtain carbon by eating plants and release it in the
form of CO2 in respiration.
3. Micro-organisms:
- fungi and bacteria return carbon to the
environment when they decompose dead plants and
animals.
The Carbon Cycle
The Nitrogen Cycle
• All organisms need nitrogen for protein, DNA & RNA
manufacture
• 78% of the Earth’s atmosphere is nitrogen gas, but it
cannot be used in this form by plants and animals.
• Nitrogen gas must first be ‘fixed’, i.e. changed to a
suitable form (ammonia or nitrate) before it can be used.
The Nitrogen Cycle
During the nitrogen cycle the following processes occur:
A – nitrogen fixation
B – assimilation
C – decomposition
D – nitrification
E – denitrification
The Nitrogen Cycle
The Nitrogen Cycle
A. Nitrogen Fixation: is the conversion of nitrogen gas into
ammonia (NH3), ammonium (NH4+), nitrate (NO3-) carried
out by volcanic action, lightning, industrial processes and
some bacteria.
B. Assimilation: nitrates are converted into plant and
animal protein, DNA and RNA.
C. Decomposition: this process is carried out by bacteria
and fungi of decay which as a result release nitrogenous
compounds such as ammonia (NH3) into the soil.
The Nitrogen Cycle
D. Nitrification:
- is the conversion of ammonia and ammonium
compounds to nitrite and then to nitrate.
- carried out by nitrifying bacteria.
E. Denitrification:
- is the conversion of nitrates to nitrogen gas.
- carried out by denitrifying bacteria
Role of Organisms in the Nitrogen
Cycle
Bacteria very important role in nitrogen cycle. Four
types:
1. Nitrogen fixing bacteria: convert nitrogen gas into
ammonia or nitrates.
1. Decomposing bacteria: convert decaying nitrogen
waste to ammonia.
2. Nitrifying bacteria: convert ammonia to nitrites then
nitrates.
3. Denitrifying bacteria: convert nitrates to nitrogen gas.
Role of Organisms in the Nitrogen
Cycle
Fungi: convert dead plants and animals and their wastes
into ammonia.
Plants: absorb nitrates from soil and use the nitrogen to
form proteins.
Animals: consume plants and use their nitrogen to form
animal protein.
Human Impact on Ecosystems
We are going to look at 3 ways that humans affect
ecosystems:
1. Pollution
2. Conservation
3. Waste Management
Note: from Syllabus Clarifications – Pollution must be
related to habitat studied.
Pollution:
o is any undesirable change in the environment. It is
caused by pollutants.
o Chemicals of human origin that harm the environment
are called pollutants.
River/Water
Pollution
Agricultural
Pollution
slurry, if it gets into a river/pond
Effect of one Pollutant from one area
Agricultural
Area
Pollutant
Slurry &
Agricultural
Fertiliser
Source
Effects
Washed or Formation of algal
leached
blooms and
from land eutrophication
Effect of one pollutant from one area
Agricultural
Eutrophication: a condition where lakes become overenriched with nutrients, resulting from excess artificial
fertilisers washed into rivers and lakes.
There is a rapid increase in the growth of alga (algal
bloom) as they use up the nutrients.
When all the nutrients are used up the algae die and are
broken down by bacteria, which use up the oxygen in the
water resulting in the death of aquatic organisms such as
fish.
Control of one Pollutant from one area
Agricultural
Area
Agricultural
Pollutant
Slurry &
Fertiliser
Control Measures
Avoid spreading these:
• on wet, waterlogged, frozen
or steeply sloping land
• within 1.5m of any
watercourse.
Pollution
Ozone Depletion:
• ozone is a gas that absorbs harmful UV radiation
from the sun
• Ozone depletion results in increased skin, cancers
& cataracts, damage to plants & the immune
systems of animals
• Ozone is broken down by manufactured
chemicals such as CFC’s
Conservation
Conservation is the protection and wise management of
natural resources and the environment.
Reasons for the conservation of organisms:
- food sources
- source of drugs
- prevent extinction
One Conservation practice
Fishing Industry
Fisheries
Fishing Net size, Quotas, Re-stocking
There is a need for continual monitoring of the
environment to ensure its protection and the wise
management of its natural resources.
Conservation Practices in Fisheries
• Fishing Net Size:
- the use of small-mesh nets can result in too
many young fish being caught.
- to prevent this use larger meshed nets to
allow the young to escape, mature and
reproduce.
• Fishing Quotas:
- overfishing has reduced fish stocks at sea.
- to prevent this fish quotas have been
assigned to different countries to ensure that
enough fish are left in the sea to replenish the
stocks.
Conservation Practices in Fisheries
• Pollution & Restocking:
- pollution of the rivers, lakes and the sea reduces
the amount of fish in these waters.
- to prevent this restock the rivers with fish from
fish farms.
- re-stocking attempts to maintain the balance in
the ecosystem.
- increases stocks for recreational fishing.
Waste Management
Waste Management: involves preventing pollution and
conserving the environment.
Examples of waste management can be seen in the areas
of:
- agriculture
- fisheries
- forestry
Waste Management
Agriculture:
• slurry results in lack of oxygen in our inland lakes as
a result of eutrophication - depletes our fish stocks.
• by controlling release of nutrients into rivers and
lakes water quality can be improved e.g storing
slurry in leak proof pits until the summer when it
can be spread on dry land.
Waste Management
Fisheries:
• Waste materials from fish consist of : heads, tails,
fins, intestines, dead fish, blood, water etc.
• The solid wastes (highly alkaline (basic)) are
neutralised using formic acid and then pulped, dried
and recycled as fertiliser or pig feed.
Waste Management
Forestry:
• Waste products include: tops of trees, small
branches, tree stumps, roots and sawdust.
• Above products are treated as follows:
- small branches, stumps, roots allowed rot
naturally feeding next generation of trees.
- tops of trees, large branches form processed
wood products e.g. MDF
Problems Associated with Waste
Disposal
• Availability of suitable landfill sites - NIMBY Syndrome
• The toxic or polluting content of fumes from incineration
(CO2, other acidic oxides and dioxins – produced from
burning plastic)
• Decaying waste produces methane gas which contributes
to the “greenhouse gases”
• Toxic chemicals may leak into groundwater supplies
(wells, lakes, reservoirs)
• Plants and animals in rivers and lakes are killed through
direct poisoning or eutrophication
Problems Associated with Waste
Disposal
• Waste disposed of in landfills can be unsightly and attract
scavengers such as rats and gulls.
• Dumping waste at sea may lead to pollution of the sea.
Role of Micro-Organisms in Waste
Management
Micro-organisms play an important role in waste
management in the following areas:
a) Landfill Sites
b) Sewage
See handout for detailed notes on the above
Control of Waste Production
The three R’s:
• Reduce
• Reuse
• Recycle
Reduce:
- reduce consumption of unnecessary goods
- reduce packaging use e.g. charge on plastic bags
Reuse:
- reuse of glass bottles
- reuse of unwanted clothing by charities
Control of Waste Production
Recycle:
- paper, glass, different metals, plastic etc.
- 40% of household rubbish is organic matter which can
be broken down to form compost (humus).
Chapter 5
Advanced Ecology
Higher Level Only
Ecological Pyramids
Ecological Pyramids can be defined as methods of
comparing different communities in an ecosystem
according to which trophic level they occupy.
Ecological pyramids – include pyramids of numbers,
mass or energy.
Types of pyramids of numbers:
- Normal
- Inverted
- Parasitic
Normal Pyramid of Numbers:
Inverted Pyramid of numbers:
One producer is supporting thousands of primary
consumers, the numbers decrease as you go up.
Parasitic Pyramid of numbers:
One producer is supporting thousands of primary
consumers, the number of organisms increase as you go
up.
Population Control
Remember:
Population: is all the members of the same species
living in an area e.g. population of humans on earth
The following factors help maintain population
numbers and bring about a ‘balance of nature’:
1. Competition
2. Predation
3. Parasitism
4. Symbiosis
1. Competition:
Occurs when organisms of the same or different species
‘fight’ for necessary resources that are in short supply.
• Intra-specific competition:
Between members of the same species i.e. within a
species e.g. fucus plants compete with each other
for space on rocks
• Inter-specific competition:
Between members of different species e.g.
blackbirds and thrushes compete for insects and
snails
1. Competition:
Two types of competition:
Contest competition
Scramble Competition
Contest Competition: involves an active physical
confrontation between two organisms – one wins
Examples:
Two dogs fighting over a bone - One may have
stronger muscles and sharper teeth and so win the
bone.
Two stags fighting over mating rights
1. Competition:
Scramble Competition: this is where each organism tries
to acquire as much of the resource as possible.
Example:
An ivy plant and a hawthorn tree may compete for
light. The ivy uses adventitious roots to grip the
hawthorn and climb higher.
1. Competition:
Adaptive techniques: are adaptations which have evolved
(developed) in response to the need to survive
competition:
e.g.1 - sharp teeth of carnivores
e.g.2 - climbing abilities in ivy
e.g. 3 - caterpillar of cabbage white butterfly chews
on cabbage leaves, while adult butterfly drinks
nectar from flowers.
2. Predation:
Predation: is the catching, killing and eating of another
organism.
Predator: animal that hunts, captures and kills other
animals (prey) for food.
Prey: the animal killed and eaten
Examples of predators and their prey:
- ladybirds and aphids
- blackbirds and earthworms
- hawks and mice
2. Predation:
Adaptations of Predators:
•Keen senses and sharp teeth
•Catch easiest prey – old and sick (less energy used)
•Change diet to suit prey available e.g. foxes
•Live and hunt in packs
•Migrate to where prey is plentiful
•Camouflage
Three examples of Adaptations of Predators
1. Hawks have excellent eye sight
2. Ladybirds have strong mouth parts
3. Cheetahs can run at 60 km/h
2. Predation:
Adaptations of prey:
•Plants may have thorns, spines or stings
•Nasty taste when eaten e.g. giant hogweed
•Are faster than their predator
•Staying in herds or flocks – safety in numbers
•Camouflage – greenfly, stick insects
Three examples of Adaptations of Prey
1. Frogs are well camouflaged
2. Zebras have stripes, when in a group lions can’t
distinguish where one ends & another begins.
3. Ladybirds contain large amounts of Formic acid so
they are unpalatable to taste
3. Parasitism
Parasitism: occurs when two organisms of different
species live in close contact and one organism (parasite)
obtains its food from and to the disadvantage of, the
second organism (the host).
Exoparasites (ectoparasites): live on the outside of the
host e.g. fleas on a dog, mosquitoes on human skin etc.
Endoparasites: live inside the host e.g. liverfluke in
cattle/sheep, tapeworms in human intestines
Parasites do harm to their hosts but usually do not kill
them too quickly.
4. Symbiosis
Symbiosis (‘living together’): occurs when two organisms
of different species live (and have to live) in close
association and at least one of them benefits.
Mutualism: is a form of symbiosis where both organisms
benefit from the association.
Note: Mutualism increases the number of both organisms
involved in the relationship.
4. Symbiosis
Examples of Symbiosis:
• Parasitism: parasite gets the benefit of food but host
is harmed.
• *A lichen is composed of an algae and a fungus
intertwined.
The algae obtains support and a mineral supply from
the fungus; the fungus obtains food from the algae.
*Rocky seashore
example
4. Symbiosis
Examples of Symbiosis:
• Bacteria living in the colon produce vitamin B2 and
vitamin K. The body absorbs these vitamins. In
return the bacteria get food and shelter.
• Nitrogen-fixing bacteria in the nodules of plants such
as clover:
The bacteria make nitrogen compounds needed by
the plant and the plant makes carbohydrates and
other food material needed by the bacteria
Population Dynamics
• refers to the factors that cause population numbers to
change.
• the numbers of predator and prey are inter-related:
As prey INCREASES predators INCREASE. As there are
more predators the prey will DECREASE. Hence predators
DECREASE. Eventually numbers of prey will increase,
starting the cycle once more.
Graph: to be done on board very important !!!
Population Dynamics
Factors which contribute to predator-prey interactions
include:
Availability of Food:
Large no. of prey cause an increase in predators. As prey
are killed off there is less food for the predators so their
numbers fall, allowing for the number of prey to rise
again.
Concealment:
When numbers of prey are very low, they can conceal
themselves so they have time to reproduce.
Population Dynamics
Movement of Predators:
If the number of prey is low, predators normally move to
an area with more prey. This also allows the prey in the
old location to increase in numbers
Human Population Growth
Population density is a measurement of the numbers of
a species over a stated area.
Population increases are due to increases in the birth
rate and immigration.
Population decreases are due to increases in the
mortality rate and emigration.
Most population numbers tend to fluctuate in the short
term, but find an overall balance in the long term
where births and immigrations are equal to deaths and
emigrations.
Mortality rates are high in nature – many organisms die
before they can reproduce.
Human Population Growth
Deaths are usually due to predation, parasites and lack of
food rather than old age.
A high mortality rate is important to populations – why?
It protects the stock of food and
eliminates the less well-adapted organisms.
Human Population Curve
Human Population Curve
Note: 1 billion = 1,000 million
Year (AD)
Population
400
1650
1930s
1970s
100 million
500 million
>2 billion
4 billion
2000
>6 billion
Population is now increasing by about 85 million per
year = 230,000 per day = 160 per minute = 2.7 per
second
Human population curve
66% of world population live in Asia. Birth rates are
declining in developed countries.
The increase in the human population is not due to an
increase in birth rates, but is caused by reduced death
rates.
Factors Affecting Human Population Growth
• Famine
• War
• Disease
• Contraception
Factors Affecting Human Population Numbers
Famine:
A lack of food leads to malnutrition and death due to
disease or starvation
Example:
Great Irish Famine of 1845 – 47, about one million
people died.
• Some countries still suffer from famine, but it is often a
problem of food distribution rather than food shortages.
• Advances in agricultural techniques have so far allowed
food supplies to match population growth.
Factors Affecting Human Population Numbers
Disease:
•Vaccines – reduce the incidence of diphtheria,
whooping cough, tetanus, polio, meningitis, TB, etc.
•Improved sanitation and insecticides – have controlled
malaria, yellow fever and sleeping sickness.
•Anaesthetics have improved surgical methods & new
drugs have saved many lives.
•Antibiotics have prevented deaths that would have
been caused by bacteria.
All of the above have helped reduce the death rate and
increase human numbers.
Factors Affecting Human Population Numbers
War:
Reduces the human population.
Effects can be temporary.
Increased birth rates (baby booms) often follow wars.
Factors Affecting Human Populations
Contraception:
Increased availability has reduced birth rates since the
1960s. Evident in developed countries e.g. in Western
Europe and USA the average family size = 2.1.
This is close to the level needed to ensure the
population remains constant.
The fertility rate in developing countries has fallen from
6.1 in 1970 to 3.5 today, due to contraception.
Study of an Ecosystem
Chapter 6
Study of an Ecosystem
• Four different investigations to be carried out and
appropriately recorded:
1. Identify any 5 fauna and any 5 flora using simple
keys.
2. Identify and use various apparatus required for
collection methods in an ecosystem (qualitative
study)
3. Conduct a quantitative study of a habitat
4. Investigate 3 abiotic factors in the ecosystem
Note: A detailed knowledge is required of any 1 fauna or
flora
Study of an Ecosystem
• Required to carry out practical investigations of any one
ecosystem
• Two types of Studies:
- Qualitative Study – records the presence or
absence of species.
- Quantitative Study – records the number of each
species.
Study of an Ecosystem
Chosen ecosystem – Rocky Seashore
Rocky Seashore
• Mixed ecosystem – it is both aquatic and terrestrial.
• Harsh Environment – no soil, wave action present,
periodic tidal changes and general exposure.
• Easy to study:
- many organisms stationary and cannot hide easily
below ground.
- shows clear changes in organisms from water’s
edge to the high rocks.
Rocky Seashore
Rocky seashore is normally divided into four zones
(based on tidal movements):
Splash Zone: is that area on the higher ground which is
rarely covered by the tide.
Upper Shore: is the area covered by high tides, but not
by normal tides.
Mid Shore: is covered by the incoming tide and exposed
at normal low tide.
Lower Shore: is only exposed at very low tides.
Rocky Seashore
Flora and Fauna
Zone
Splash
Upper Shore
Mid Shore
Lower Shore
Flora
Sea Pink
Lichens
Channel Wrack
Spiral Wrack
Bladder Wrack
Serrated Wrack
Corallina
Fauna
Black Periwinkles
Shore Crabs
Sand Hoppers
Barnacle
Dog Whelk
Limpets
Mussels
Edible Periwinkles
Sponges
Flat Periwinkles
Rocky Seashore
Adaptations within a seashore habitat
Adaptations of the previously listed fauna and flora
(and more) are outlined on handout
Remember must know 5 fauna and 5 flora
Effects of Abiotic Factors and Methods of Measurement for
Rocky Seashore
Abiotic Factor
Influence/Effect
Measured by
Exposure
Different species of plants and animals are found on Profile Map
different zones of the shore e.g. 3 species of wrack, (pg56/57)
limpets restricted to mid shore
Temperature
Different species of plants and animals have a
tolerance for a different maximum temperature e.g.
4 species of periwinkle each of which is limited to
certain regions of shore due to temperatures.
Thermometer
Wave Action
High wave action forces plants higher on the shore
and favours species with narrow fronds e.g. Thong
weed, corallina
Compare
sheltered and
exposed
habitats
Rocky Seashore
Please see handout for detailed study of 2 fauna
and 2 flora and the factors affecting them within
a rocky sea shore ecosystem
Study of an ecosystem – Rocky Seashore Habitat
A habitat study involves five main steps:
1. Draw a map
2. Identify 5 fauna and 5 flora
3. Carry out qualitative and quantitative studies
4. Measure 3 abiotic factors
5. Present the information gathered
Remember:
- Qualitative Study – records the presence or absence of
species
- Quantitative Study – records the number of each
species
Step 1: Mapping the habitat
In general when a habitat is studied a plan view and if
necessary a profile transect (indicates land sloping
down to a seashore) is drawn.
For further details please see pg’s 55 – 56 in book
Step 2: Identify 5 fauna and 5 flora
Using simple keys and pocket guide books you will be
able to identify 5 fauna and 5 flora.
The following rules should be followed in order to be
sensitive to the ecology of the ecosystem:
- Follow countryside Code
- Only collect an organism if it is absolutely
necessary and you cannot identify it in the field
- Return organisms to the habitat if possible
- Leave the habitat as you found it
- Beware of dangers such as deep waters, waves,
thorns, stinging insects, bulls, dogs etc.
Step 3: Carry out Qualitative and Quantitative
Studies
• A qualitative study: simply records the presence/absence
of a species
• This type of study is carried out by identifying the
species directly in the habitat or by collecting and later
identifying the species.
Equipment used in the qualitative study of a habitat:
Plants
• collected by breaking off a piece of the plant and storing
in labelled plastic bags.
Animals
Baerman funnell
Used to extract anthropods,
worms from a soil sample.
Light and heat cause the
organisms to move out of the
muslin bag and into the bottom of
the funnel where they are
collected for examination under a
microscope.
Animals:
Tullgren Funnel
Used to extract animals
e.g. centipedes, milipedes
from soil by heating the
soil on one side
The animals are driven
out of the soil by heat
from a lamp and fall
through a wire gauze
Animals:
Sweep Net
Used to collect insects from tall grass
Plankton Net
Drawn through water from a
rock or a boat.
Used to collect microscopic
plants and animals from pools
and streams e.g. plankton
Animals:
Pitfall Trap
Jam jar buried in ground and covered
with raised flat stone.
Used to collect ground surface animals
insects, e.g. spiders, centipedes,
woodlice, beetles, periwinkles etc.
Beating tray
This is a white tray, cotton sheet or
large sheet of white paper.
It is placed under a bush or tree
branch.
The tree branch is shaken suddenly
and vigorously.
Insects, spiders and other invertebrates
fall onto the tray.
Animals:
Pooter
Used for picking up very small
animals.
Suck through mouthpiece (end of
which is covered with muslin) and
the animal (insects, spiders, sand
hoppers) is taken into jar through
the hose
Mammal Trap
Used to collect small mammals
e.g. mice, shrews, etc.
Animals:
Cryptozoic trap
A piece of wood or stone which is left on the ground.
After a suitable interval, animals (which prefer dark or
moist conditions) such as slugs, woodlice, centipedes
and millipedes will be found underneath.
Step 3: Carry out Qualitative and Quantitative
Studies
• A quantitative study gives the numbers of each species
that are in the habitat.
Quantitative Study of Plants (Black square):
1. Percentage Frequency:
- throw the quadrat 10 times
- mark the presence or absence of the organism
% Frequency = no. of quadrats with organism present x 100
no. of quadrats thrown
1
Quantitative Study of Plants:
2. Percentage Cover (White square with 24 smaller squares
inside):
- decide on organism to study
- throw quadrat 10 times
- record the no. of hits (presence of organism at sample
points)
% Cover =
No. of hits
x 100
No. of possible hits
1
3. *Population Density (Black square)
- find the average no. of organisms in each of 10 quadrats
- find the area of the quadrat in m2
- Express as organisms per m2 (mpy. the average no. of
organisms by the area of the quadrat)
Quantitative Study of Plants:
4. Line Transect:
- a line transect is a rope marked at 1m intervals
used to calculate the distribution of plants based on
the number of times they touch
Note: See also Belt Transect – pg. 62 book
Quantitative Study of Animals:
Capture – Recapture Method
- this method is used to estimate the number of moving
animals in a given area.
Method:
- locate and capture animal you wish to study, mark/tag
animal
- release them
- a day later capture another sample and count the
number caught on the 2nd visit that had been tagged
on the 1st.
Quantitative Study of Animals:
Capture-Recapture Method
Population Size = C1st x C2nd
M2nd
where, C1st = no. of animals caught and marked on 1st visit
C2nd = no. of animals caught on 2nd visit
M2nd = no. of animals marked on 2nd visit
Step 4: Measure 3 Abiotic Factors
The three abiotic factors will be those mentioned
previously and will be measured using appropriate
instruments. Note: Other factors will also be investigated.
Step 5: Record and Present the information
Gathered
On the day you will be given a handout to record all
measurements etc. taken but please note yellow
box at bottom of pg. 66 with regard to step 5 !!!!
Sources of Error in Studying an Ecosystem
Please see handout for detail of these !!!