Living Environment - Sampling, Abiotic Factors and Keys

Question 1

Examples of Biotic factors

Answer 1

• grazing
• predation
• competition
• land use
• habitat destruction
• overfishing
• disease
• conservation

Question 2

Examples of abiotic factors

Answer 2

• air temperature
• soil pH
• light intensity
• pollution levels
• rock type
• soil moisture
• oxygen concentration
• nutrients
• water flow rate
• wind speed
• salinity

Question 3

Animal competition

Answer 3

• food
• water
• space
• mates for reproduction

Question 4

Plant competition

Answer 4

• light
• water
• space
• nutrients

Question 5

Importance of random sampling

Answer 5

Means every individual in a population has an equal chance of being selected

Question 6

How to increase reliability

Answer 6

Take more/larger sample

Question 7

How to reduce sources of error

in experimental practice

Answer 7

Use keys to identify organisms and equipment should be calibrated and used appropriately

Question 8

quadrat

sampling technique

Answer 8

• 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

Question 9

pirfall trap

sampling technique

Answer 9

• 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

Question 10

camera trap

sampling technique

Answer 10

• 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

Question 11

mammal trap

sampling technique

Answer 11

• 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

Question 12

pond netting

sampling technique

Answer 12

• 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

Question 13

sweep net

sampling technique

Answer 13

• 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

Question 14

capture, mark, recapture

sampling technique

Answer 14

• 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

Question 15

transect

sampling technique

Answer 15

Using any sampling technique at equal intervals along a straight line

Question 16

light intensity

measuring terrestrial abiotic factors

Answer 16

• 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

Question 17

soil moisture and pH

measuring terrestrial abiotic factors

Answer 17

• 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

Question 18

temperature

measuring terrestrial abiotic factors

Answer 18

• 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

Question 19

wind speed and direction

measuring terrestrial abiotic factors

Answer 19

• 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

Question 20

precipitation

measuring terrestrial abiotic factors

Answer 20

• measured with rain gauge, read level of water on the scale
• keep above the ground to avoid rain spashing into the gauge

Question 21

water flow rate

measuring aquatic abiotic factors

Answer 21

• 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)

Question 22

oxygen concentration

measuring aquatic abiotic factors

Answer 22

• 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