investigation population

Question 1

how do you study a habitat

Answer 1

you need to count the number of individual of a species in a given space - abundance

Question 2

why do we use samples

Answer 2

because it is impossible to count every organism and in doing so would damge the habitats

Question 3

what is a point quadrat

Answer 3

a horizontal bar supported by two lefs

at set intervals are ten holes which a pin may be droped and the species that touches the pin is recorded

Question 4

what is a frame quadrat

Answer 4

square frame divided by string or wire into equal subdivisions , the quadrat is placed in different areas with the abundance of each species within a quadrat then recorded

Question 5

why doe we need to think about the size of the quadrat being used

Answer 5

this will depend on the size of plant or animal being counted and their distribution larger species require larger quadrats

Question 6

what do we need if the population is unevenly disribulted

Answer 6

large number of small quadrat samples

Question 7

what does a larger number of sampkle quadrat mean

Answer 7

the more reliable the results will be

Question 8

as the nuber of different species increase what needs to be increase

Answer 8

the nuber of quadrats used

Question 9

what must the position of the quadrat be

Answer 9

random sampling to produce statistically significant results

Question 10

how to set out random sampling of two different field

Answer 10

choose fields that are close together to avoid, differnet soil conditions and tempo and water ect
lay two tapes at right angle
obtain a series of coordinates from generator
place quadrate on intersect of coordinates and record the species

Question 11

why do we use systematic sampling

Answer 11

it is more informative especially wen there is gradual chanfe along a line of succession

Question 12

how to do a belt transect

Answer 12

stretch a string ot tape across the ground in a straight line ,
a frame quadrat is laid alongside the tape and species recorderd
the quadrat is then moved across it length and recorded

Question 13

what is abundance

Answer 13

the number of individuals of species living in a certain area at a given time

Question 14

how do we measure frequency

Answer 14

it is the likelihood that a particular species will appear in a quadrat eg if a bee appeared in 15/ 30 of the quadrats the frequency is 50%

Question 15

what is percentage cover

Answer 15

estimate of the area within a quadrat that a species covers , useful when a species is particulary abundant

Question 16

what is the benfit of using these techniques

Answer 16

data can be collected rapidly and individual plants do not need to be counted

Question 17

why cant we use quadrats for motile organisms

Answer 17

they move when they are approached they are often hidden and are difficult to find and identify

Question 18

how do we measure the abundance of animals

Answer 18

known number of animals are caught
marked in some way
release
some time later a given number of organisms are captured and the number of marked individuals are counted and recorded

Question 19

the size of the population is counted by

Answer 19

total individuals in first x total individuals in second sample/ number of marked individuals

Question 20

what does capture and recapture rely on

Answer 20

the proportion of marked to unmarked is ame first and second time round
no new deaths no new birth
no immigration or emigration
mark not rubbed off