Presentation on theme: "Sampling techniques and the measurement of abiotic and biotic factors"— Presentation transcript:
1Sampling techniques and the measurement of abiotic and biotic factors
2Previously we learnt about abiotic factors that could affect biodiversityWhat is the definition of an abiotic factor?A non-living factor in an ecosystem that caneffect organisms.What are some abiotic factors in an ecosystem?Light intensity, temperature, pH and soil moisture
3Previously we learnt about biotic factors that could affect biodiversityWhat is the definition of a biotic factor?A living factor in an ecosystem that caneffect organisms.What are some biotic factors in an ecosystem?Predation, competition, diseases
4Today we are learning about how abiotic factors can be measuredand errors avoided when measuringthemhow to use a quadrat and pitfall trapsto assess the numbers of organisms inan ecosystem
5Abiotic factors include light intensity, temperature, pH and soil moisture. These are easy to measure using simple equipment.Link the abiotic factor with the equipment used to measure it?Light intensity moisture meterTemperature pH probe or meterpH thermometerSoil moisture light meter
6Easy!The teacher will now explain how to use theEquipment for measuring abiotic factors,how to avoid errors when usingthe equipment and any limitations there mightbe with the technique.(Most of this is a re-cap of work done in S1 Science)
7Light intensitySelect the correct position if the meter has a switchPut the meter in the area to be measured pointing the sensor area at the source of lightRead the correct scale and repeat a number of times for the area.
8The ERRORS to be avoided include correct switch position and NOT shading the sensor. The limitation is that light intensity changes with day time and cloud cover.
9For which group of organisms might light intensity be most important?Why might light intensity be important to these organisms?
10pH and soil moisture(Often measured by the same meter)Select the correct position if the meter has a switch.Put the probe in the area to be measured, coveringonly the tip.Read the correct scale,wipe the probe andrepeat a number oftimes for the area.
11The ERRORS to be avoided include correct switch position and wiping the probe after each measurement is taken.Not wiping the probewill give a false reading.
12For which group or groups of organisms might pH of their environmentor soil moisture be important?Why might pH or soil moisture be important to these organisms?
13TemperaturePut the thermometerin the ground or waterand leave for the heatto take effect.Read the scale and carefully, wipe the thermometer and repeat a number of times for the area.
14For which group or groups of organisms might the temperature of theirEnvironment be important?Why might temperature be important to these organisms?
15The abundance of animals and plants in an area can be estimated using a numberof sampling techniques includingquadrats and pitfall traps.These techniques only give an estimaterepresentative sample and only ifenough replication is carried out.
16QuadratsThese are a square frame sub-dividedinto smaller squares.They are often 0.5m by 0.5m divided into25 smaller squares but can be muchsmaller or bigger depending on the studyarea.They can be used in a random manneror along a transect line.
17QuadratsThese are a square frame sub-dividedinto smaller squares.
18Quadrats used randomly to get an overall abundance in an area. Quadrats used on a transect line to help understand the changes in plants in a specific area.
19QuadratsThese give a representative samplein a small area.Enough samples must be taken in relationto the size of area studied.They can be used to generate results fora larger area.
20Pitfall trapsThese are used to collect samples of small organisms moving along the surface of the soil.Dig a hole and place a pot in it, level with theground.Put on a cover(stone) and leaveovernight.Check for organismsthe next day.
21Pitfall trapsOnly useful for small organisms.Some organisms may eat others.Organisms need to be identifiedIt gives a representative sample of the area.
22What have you learned today? Explain the meaning of abiotic factor?What are 4 typical abiotic factors?How can these factors be measured?What errors can be made measuring them?Explain the meaning of biotic factor?What are 2 techniques used to sample organismsin an area.