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

WoodlandHedgerow

SeashoreMarine

Grassland Freshwater Tree, etc.

Can you name some more?

To study an ecosystemWe 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 shelterspace lightfood

Environmental factors that affect organisms

Abiotic

Biotic

Climatic

Edaphic

*Aquatic

Abiotic Factors

•Temperature•Light intensity•Air speed•Water current•Humidity

•pH•Dissolved oxygen•Salinity•Nitrate, phosphate and other plant nutrients

Abiotic are non-living factors

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 are the average weather conditions that affectthe community in an ecosystem.

Climatic factors

•Temperature•Rainfall•Humidity•Wind •Light intensity (including seasonal variations)•Day length

Edaphic FactorsEdaphic 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.

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

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 EcosystemIs the pathway of energy transfer from one organism to the next in an ecosystem due to feeding, e.g. along a food chain

Food ChainIs 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 ChainHoneysuckle 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 LevelThe 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 Trophic LevelPlankton 1st Barnacle 2nd Whelk 3rd Crab 4th

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 NumbersTypes 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 Webthe interconnected food chains in an ecosystem e.g.

Seashore Food Web

Food NicheA 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 RecyclingThere 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 RecyclingThese 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 RecyclingNutrient 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 CycleRole 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 CycleDuring the nitrogen cycle the following processes occur:

A – nitrogen fixation

B – assimilation

C – decomposition

D – nitrification

E – denitrification

The Nitrogen Cycle

The Nitrogen CycleA. 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 CycleD. 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.

2. Decomposing bacteria: convert decaying nitrogen waste to ammonia.

3. Nitrifying bacteria: convert ammonia to nitrites then nitrates.

4. 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 EcosystemsWe are going to look at 3 ways that humans affect

ecosystems:

1. Pollution2. Conservation3. 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.

Agricultural Pollution

slurry, if it gets into a river/pondRiver/Water

Pollution

Effect of one Pollutant from one area

Agricultural

Area Pollutant Source Effects

Agricultural Slurry & Fertiliser

Washed or leached from land

Formation of algal blooms and eutrophication

Effect of one pollutant from one area

AgriculturalEutrophication: a condition where lakes become over-enriched 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 areaAgricultural

Area Pollutant Control Measures

Agricultural Slurry & Fertiliser

Avoid spreading these:• on wet, waterlogged, frozen or steeply sloping land• within 1.5m of any watercourse.

PollutionOzone 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

ConservationConservation 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 practiceFishing 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 Sitesb) 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 5Advanced 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 ControlRemember:Population: is all the members of the same species living in an area e.g. population of humans on earthThe following factors help maintain populationnumbers and bring about a ‘balance of nature’:

1. Competition2. Predation3. Parasitism4. 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: involves an active physical confrontation between two organisms – one winsExamples:

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

Contest competition

Scramble Competition

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 ivye.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 Predators1. Hawks have excellent eye sight2. Ladybirds have strong mouth parts3. 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 Prey1. Frogs are well camouflaged2. 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. ParasitismParasitism: 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 aremore predators the prey will DECREASE. Hence predatorsDECREASE. Eventually numbers of prey will increase, starting the cycle once more.

Graph: to be done on board very important !!!

Population DynamicsFactors 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.

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 andeliminates the less well-adapted organisms.

Human Population Growth

Human Population Curve

Human Population Curve

Year (AD) Population

400 100 million1650 500 million1930s >2 billion1970s 4 billion

2000 >6 billion

Note: 1 billion = 1,000 million

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

• Disease

• War

• 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 NumbersDisease:•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 habitat4. 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 SeashoreRocky 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 SeashoreFlora and Fauna

Zone Flora FaunaSplash Sea Pink

LichensBlack PeriwinklesShore Crabs

Upper Shore Channel Wrack Sand HoppersBarnacle

Mid Shore Spiral WrackBladder Wrack

Dog WhelkLimpets

Lower Shore Serrated WrackCorallina

MusselsEdible PeriwinklesSpongesFlat 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 byExposure Different species of plants and animals are found on

different zones of the shore e.g. 3 species of wrack, limpets restricted to mid shore

Profile Map (pg56/57)

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 map2. Identify 5 fauna and 5 flora3. Carry out qualitative and quantitative studies4. Measure 3 abiotic factors5. 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 floraUsing 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 funnellUsed 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

Sweep NetAnimals:

Used to collect insects from tall grass

Plankton NetDrawn 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 trayThis 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: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

Pooter

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

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

Population Size = C1st x C2nd M2nd

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 !!!