Living Environment - Sampling, Abiotic Factors and Keys Flashcards
Examples of Biotic factors
- grazing
- predation
- competition
- land use
- habitat destruction
- overfishing
- disease
- conservation
Examples of abiotic factors
- air temperature
- soil pH
- light intensity
- pollution levels
- rock type
- soil moisture
- oxygen concentration
- nutrients
- water flow rate
- wind speed
- salinity
Animal competition
- food
- water
- space
- mates for reproduction
Plant competition
- light
- water
- space
- nutrients
Importance of random sampling
Means every individual in a population has an equal chance of being selected
How to increase reliability
Take more/larger sample
How to reduce sources of error
in experimental practice
Use keys to identify organisms and equipment should be calibrated and used appropriately
quadrat
sampling technique
- plants or slow moving organisms
- randomly place the quadrat onto the ground and count how many square an organism is present
- errors include: some organsims may be partioaly inside the quadrat; the area isnt a good represantation of the ecosystem
- solving: set rules to ensure it is fair eg. top and right is in and bottom and left is out; take several samples to increase reliability
pirfall trap
sampling technique
- small terrestrial invertibraes eg. woodlice
- dig hole into ground and place into ground, cover the trap but ensure that the cover is elevated to allow organisms to fall into trap
- errors include: container not level with the ground; birds eating sample
- solving: keep container level to the soil to ensure reliability of the sample; camouflage the trap to stop the birds from eating the sample
camera trap
sampling technique
- medium to large mammals and birds
- Digital camera sees a warm object or movement and takes photo or video
- errors include: where to find animal; animal needs to be seen
- solving: research the place where the animal will be found; place at correct hight for animal to be seen
mammal trap
sampling technique
- small, terrestrial mammals
- bait attracts the mammal and either a door closes (trapping the animal), hair is caught or footprints are made
- errors include: ‘trap shy’ animals; cant distinguish mammal from sample
- put in the area before test to animals get used to it; use a key for identification
pond netting
sampling technique
- freshwater organisms
- move net through water to collect animals or kick substrate in front of the net and collect sample
- errors include: animals can escape
- use appropriate sized netting so that the animals cannot escape
sweep net
sampling technique
- small insects from grass or other vegetation
- sweep net through vegetation after every step
- errors include: its raining and there is no insects; all falling to floor
- solutions: sample on a sunny day; tilt net upwards to collect the organisms
capture, mark, recapture
sampling technique
- used to estimate the population of any animals you want but its easier with animals that have shells or exoskeletons
1. random smaple is captured, counted and marked (M)
2. they are released
3. another random sample is taken and counted (C) aswell as the number of marked re-found (R)
4. use the formula N = MC/R - errors: not an accurate representation of the population size
- solution: take a larger sample
transect
sampling technique
Using any sampling technique at equal intervals along a straight line
light intensity
measuring terrestrial abiotic factors
- plants need sunlight to photosynthesise and some animals are sensative to light
- the panel/sensor is held towards the light and the value can be read from the scale
- avoid covering panel with body/shadow
soil moisture and pH
measuring terrestrial abiotic factors
- without water life on earth could not exist so it effects the distribution of all organisms
- the moisture/pH meter probe is inserted to a set depth and the value is recorded from the scale
- avoid cross contamination of soil by wiping the probe
a chemical test can be done for soil pH but it is more complicated
temperature
measuring terrestrial abiotic factors
- temperature effects enzyme activity
- theremometer is used and value recorded
- values can be effected by body temperature and direct sunlight - keep in shade and hold in correct place
wind speed and direction
measuring terrestrial abiotic factors
- vegetation can be affected by wind speed as tall vegetation can be uprooted by high speed winds
- anemometer held at arms length above head and the value is recorded
- avoid covering the wind with your body
wind direction use a wind vane and be carful when reading direction
precipitation
measuring terrestrial abiotic factors
- measured with rain gauge, read level of water on the scale
- keep above the ground to avoid rain spashing into the gauge
water flow rate
measuring aquatic abiotic factors
- measure depth and width of river and calculate area (a = lb)
- measure set distance (eg. 1m) and record the time it takes for an object to travel down the river of the set distance and caculate velocity (v = d/t)
- calculate water flow rate (water flow rate = area x velocity)
oxygen concentration
measuring aquatic abiotic factors
- aquatic organisms need oxygen to survive
- insert probe into water and swirl, record results
- remember to wash with distilled water before next use to combat cross contamination
