Practical 12

Question 1

list 3 abiotic factors

Answer 1

light intensity
temp
water supply
nutrient supply
humidity
wind speed
day length
rainfall

Question 2

list 3 biotic factors

Answer 2

competition for resources
predation
disease

Question 3

how is percentage cover calculated

Answer 3

use a quadrant with squares. count how many squares the required species is present in. only count sure if more than half of the square is filled. calculate the percentage of square the species is present in

Question 4

outline the procedure to this practical

Answer 4

1. choose an are to take samples from. use a random number generator to generate 10 sets of coordinates
2. use two tape measurers to create a set of axes off which coordinates can be read
3. place the quadrant at each of the coordinates. placing the bottom left corner on the coordinate every time
4. record the percentage cover for the chose species
5. at each coordinate a measure of the independent variable should be taken (light intensity, etc.)

Question 5

how can the results be used to determine the relationship between the chosen factor and the percentage cover

Answer 5

use statistical test (spearman’s)

Question 6

why should a random generator be used

Answer 6

to avoid bias in random sampling

Question 7

state the formula for the mark release recapture method

Answer 7

population= no in 1st sample*no in 2nd sample / no marked in 2nd sample

Question 8

state the assumptions when using the mark release recapture method

Answer 8

no births, deaths or immigrations
random mixing of marked individuals with population
marking does not affect behaviour of individuals or make them more vulnerable to predators