Investigating Ecosystems 2

Question 1

Where to collect data:

Answer 1

Quadrats, transects

Question 2

What areas including abiotic factors do you need to know how to measure?

Answer 2

Marine
Freshwater
Terrestrial

Question 3

How can you measure abundance?

Answer 3

Lincoln index and simpsons diversity index

Question 4

How can you place quadrats randomly?

Answer 4

Map out study area
Draw grid over it
Number each square
Use random number generator to choose which squares to sample

Question 5

What is a stratified number sample?

Answer 5

When there is an obvious difference within an area and two sets of samples are taken

Question 6

How do you place quadrats with a stratified sample?

Answer 6

Deal with each area separately
Draw a grid for each area
Number the numbers in each area
Use a random number generator

Question 7

What is a transect?

Answer 7

A line in which you record the occurrence and or distribution of plants and animals in a particular study area

Question 8

What is a line transect

Answer 8

String or measuring tape which is laid out in the direction of the environment gradient and species touching the string or tape are recorded

Question 9

What is a belt transect?

Answer 9

Two lines are laid out a certain width apart and the individuals between them are sampled

Question 10

What is a continuous transect?

Answer 10

When the whole line or belt is sampled

Question 11

What is an interrupted transect?

Answer 11

Samples are taken at regular points along the line. Quadrats are placed at these points

Question 12

Outline a method to measure turbidity

Answer 12

Attach a black and white secchi disk to a rope
Slowly lower the disk until it disappears from view.
Record the depth of the rope.
Repeat and calculate average depth

Question 13

How do you ensure reliable results when measuring turbidity?

Answer 13

Always stand or always sit, choose one.
Always wear your glasses.
Always work on the shady side of the boat.

Question 14

How do you measure plant biomass?

Answer 14

Place quadrat
Harvest all above ground vegetation in quadrat
Wash it to remove insects or dirt
Dry it at about 60-70 degrees until it reaches a constant weight. This mass is a dry weight.
Repeat for accuracy.
Times it by total quadrat areas of plants.

Question 15

Humane ways to trap small motile animals:

Answer 15

Pitfalls
Sweep nets
Tree beating

Question 16

Describe the Lincoln index method:

Answer 16

Establish study area
Capture a sample of the population
Mark each organism captured and record how many you marked, do this in a safe way that does not expose them to higher predation levels.
Release them into the environment and allow for efficient time to remix with the population
Take second sample and count how many are already marked

Question 17

What is the Lincoln index formulae?

Answer 17

 M2

N1 = marked first time
N2 = captured second time
M2 = marked animals in second sample

Question 18

How to measure simpsons diversity index?

Answer 18

D = N(N-1)
       --------
       Sum of (n(n-1)

N is total number of organisms of all species found
n is number of individuals of a particular species.