1.5.1 broad overview of a selected ecosystem

1.5.1 Broad overview of a selected Ecosystem

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Note from the syllabus

* Emphasis in this special study should be placed on the techniques of fieldwork and the recording and analysis of collected data.

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Selecting an Ecosystem

• The ecosystem selected should have a variety of flora and fauna

• Easy to get to – you may want to return during a different season

• An area within the school may be suitable e.g. hedgerow, waste ground, base of a fence where grass is not cut, a length of wall, pond, path, etc.

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What to observe in an Ecosystem

1st Form a general overview • Name the type of habitat• Observe if it is exposed, sheltered, flat, on a

slope, what direction does it face, influence of wind – direction, intensity, drainage, etc.

2nd The diversity of flora and fauna in the ecosystem

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What to examine broadly

• A minimum of five flora and five fauna• Name each organism – examine the range

of variation of any single species e.g. height, mass, colour, etc.

• Does the same species of plant grow in bright and dark areas of the habitat e.g. ivy – note the difference in leaf size and colour in each area.

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What to observe in an Ecosystem

3rd Look for inter-relationships between the various living organisms in the ecosystem

4th What is the influence of the non-living (abiotic) components on the flora and fauna of the ecosystem?

1.5.2 Ecology Equipment

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Baermann funnell• Used to extrract

nematodes 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 and identification.

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Tullgren Funnel• Used to extract

animals 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

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Grapnel• a plant grab. It

consists of a sturdy pole with barbs at one end

• When the grab is plunged into aquatic vegetation the plants become entangled in the barbs and can be pulled onto dry land.

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Insect net

• Used for catching flying insects.

• The net part should be sufficiently long so that the mouth frame seals off the end of the net which contains the catch when the net is laid flat.

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Fish Net

• Used to collect small fish from pools and streams

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Plankton Net

• Used to collect microscopic plants and animals from pools and streams

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Sweep Net

• Used to collect insects from tall grass

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Pooter

• Used for picking up very small animals.

• Suck through mouthpiece (end of which is covered with muslin) and the animal is taken into jar through the hose

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Sieve• Organisms that

live in leaf litter can be extracted by using a sieve with a mesh size of about 5 mm.

• Use the sieve over a beating tray or a large sheet of paper.

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Cryptozoic trap

• A piece of wood or stone which is left on the ground.

• After a suitable interval, animals such as slugs, woodlice, centipedes and millipedes will be found underneath.

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Mammal Trap

• Used to collect small mammals

• e.g. mice, voles, etc.

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Pitfall Trap

• Jam jar buried in ground and covered with raised flat stone.

• Used to collect ground surface animals insects, nocturnal and diurnal

• e.g. spiders, centipedes, woodlice, beetles, etc.

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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 and other invertebrates fall onto the tray.

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Settlement tray• This is used in freshwater. • It consists of a shallow wooden frame

which has a metal gauze or perforated zinc sheet bottom.

• The tray is placed on the bottom of a pond or stream and is covered with gravel or mud and is left in place for a month or more.

• It is then carefully removed and examined and the organisms which have settled on it are recorded.

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Environmental Comparator

• An electronic device often with a digital display

• Used for accurate measurement of different environmental abiotic factors e.g. temperature, pH, light intensity, etc.

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Light meter

• Used to measure the light intensity

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A Quadrat• A frame that forms a

known area usually 0.5m X 0.5m = 0.25m2

• Usually square shaped

• Can be used to measure:

Frequency and

% Cover

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Homemade Quadrat Internal area = 0.25m2

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Quadrat with marker

1.5.3 Organism Distribution

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Qualitative survey

• a study determining the presence/absence of a substance or organism in a sample or habitat

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Quantitative survey

• a study determining the amount of a substance or number of an organism present in a sample or habitat

• Conduct a quantitative study of plants and animals of a sample area of the selected ecosystem using frequency and percentage cover techniques.

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Your Results

• Transfer results to tables, diagrams, graphs, histograms, or any other relevant mode.

• Identify possible sources of error in such a study.

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A website worth checking out

If you are connected to the internet click on the folowing link

http://www.skoool.ie/skoool/examcentre_sc.asp?id=2896

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Need to know

• Explain the difference between a Qualitative & Quantitative study for plants and animals.

• Complete experiments to evaluate frequency and % Cover for both plants and animals

1.5.4 Choice of Habitat

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Choice of Habitat

Relationship between an organism’s suitability to its habitat and abiotic factors to include measurement of any three of the following:

• Mineral content• Percentage air in soil• Percentage water in soil• Percentage humus• Salinity• Degree of exposure• Slope

• pH• Temperature (air and ground or aquatic)• Light intensity• Water current• Air current• Dissolved oxygen

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From ‘Syllabus Clarifications’

• 1.5.4 Keep it simple – presence or absence of the abiotic factor will suffice.

• Measure simply – e.g. temperature. Relate the abiotic factor to the ecosystem being studied.

• Three (3) suitable factors that are relevant /present in the habitat from the list above. Investigate these factors in the investigation. Suitability to habitat. (Syllabus P13, Teacher Guidelines P23).

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Need to know

• Show how the range of organisms living in a habitat are determined by the abiotic factors present

• Investigate and report on any 3 Abiotic Factors.

1.5.5 Organism Adaptations

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Organism Adaptations

• Necessity for structural, competitive or behavioural adaptation by organisms

• Note an adaptation feature by any organism in your selected ecosystem

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Need to know

• Explain the necessity for and give examples of Structural / Competitive / Behavioural adaptations

• State one adaptation by one organism in the selected ecosystem

1.5.6 Organism Role in Energy Transfer

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Organism Role in Energy Transfer

Identify of the role of the organisms studied in the pathways of energy flow by construction of:

• Food chains• Food web• Pyramid of numbers

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Need to know

• Explain and identify the role of the organism in energy transfers.

• Construct: – A food chain, – A food web and – A pyramid of numbers of the study area