Nat5 Biology Unit Three Life On Earth Key Area 2 Distribution of organisms

Question 1

What are some examples of biotic factors?

Answer 1

Competition for resources, disease, food availability, grazing and predation

Question 2

What are some examples of abiotic factors?

Answer 2

Light intensity, moisture, pH and temperature

Question 3

What would you use to measure temperature?

Answer 3

Thermometer or a temperature probe

Question 4

How do you use the temperature measuring equipment?

Answer 4

Insert the probe into soil and wait until the reading has stabilized , make sure that the equipment returns to room temperature after every use or just replace it

Question 5

How do you measure pH?

Answer 5

With a pH meter or chemical test (pH indicator)

Question 6

How do you use the pH testing equipment?

Answer 6

Insert pH probe or meter into the soil and read from the scale, make sure to wipe the probe after every use

Question 7

How do you measure light intensity?

Answer 7

Using a light meter

Question 8

How do you use the light intensity intensity measuring equipment?

Answer 8

Hold the light sensitive panel towards light to be measured and read result from scale. Make sure that you are not casting a shadow over the over the panel

Question 9

How do you measure soil moisture?

Answer 9

Using a moisture meter

Question 10

How do you use the soil moisture measuring equipment?

Answer 10

Insert the probe into the soil and read the level from the scale. Make sure to wipe the probe to ensure that’s moisture from a previous reading does not affect the results

Question 11

How do pitfall traps work?

Answer 11

You create a small hole in the ground place a container into it so it aligns with the soil, and any small organism which are crawling along the surface will fall into the container

Question 12

What are possible sources of error with the pitfall trap?

Answer 12

Organisms may not be able to climb into the container
Trapped organisms may be eaten by birds
Trapped organisms may eat each other

Question 13

How do we minimize errors in the pitfall trap?

Answer 13

Make sure that’s the container is in line with soil surface
Cover trap with a raised stone or leaf to create a roof
Use a preservative such as 50% ethanol to euthanize the organisms in the traps or check traps regularly

Question 14

What are some limitations in the pitfall trap?

Answer 14

Typically only suitable for small surface-crawling invertebrates. The size of the pitfall trap can limit what can successfully be caught

If the number of pitfall traps set is low then the results may not be representative of the area as a whole

Question 15

How do quadrats work?

Answer 15

It is a 50cm2 or 1m2 square/rectangular frame, it can be one big square of can have lots of smaller squares inside the frame. You randomly throw it where you want to research

Question 16

What are possible sources of error with the quadrat?

Answer 16

Quadratic may not be placed randomly so the abundance of particular organisms cannot be accurately estimated (it could be biased)
Some plants that’s are partly in the quadrat are recorded and other are not

Question 17

How do we minimize errors in the quadrat?

Answer 17

Ensure that quadrants are placed at random

Establish a rule for plants that are partially included and apply consistently to all quadrats in the study

Question 18

What are some limitations of the quadrat?

Answer 18

Typically only suitable for small, low growing plants and very slow moving small animals due to the quadrats size and how they are placed

If the number of quadrats placed is low then the results may not be representative of the area as a whole

Question 19

What are paired statements key used for?

Answer 19

Keys are used to help identify the species that’s organisms belong to.

Fur present: Mammal
Fur absent: Go to question 2

Question 20

What is an Indicator Species?

Answer 20

Species that indicate environmental quality or levels of pollution by their presence, absence or abundance.

Question 21

What factors can cause an increase or decrease in biodiversity?

Answer 21

Predation
Grazing
Temperature
pH