Distribution Of Organisms

Question 1

What are examples of abiotic factors?

Answer 1

• Light intensity
• pH
• Temperature
• Moisture

Question 2

What are examples of biotic factors?

Answer 2

• Predation
• Competition for resources
• Disease
• Food availability
• Grazing

Question 3

What do they affect?

Answer 3

These factors affect the distribution of organisms (how spread out they will become)

Question 4

How do you measure light intensity? And what is an error that should be avoided?

Answer 4

Light intensity can be measured with a light meter.

One error of measuring includes the light meter being in shade or covered by something.

This can be avoided by ensuring you are in the sun and your hand (or anything else) is not in the way of the panel.

Question 5

How can you measure soil moisture and pH?

Answer 5

Soil moisture can be measured with a moisture meter by placing the probe into the soil.

The pH can also be measured the same way with the pH meter.

An error in measurements could occur if the probe has not been wiped between readings

Question 6

How can air and soil temperature be measured?

Answer 6

A thermometer can be used to measure the temperature of the air

A temperature probe can be used to measure the soil

Question 7

What is a quadrat and how is it used?

Answer 7

A quadrat is a square grid used to measure the number of/sample plants in an area

It should be thrown randomly in the area and each square containing a certain species of plant should be counted (not how many of each there are in a square!)

Make sure to throw it multiple times to get a reliable representation of the area

Question 8

What is a pitfall trap?

Answer 8

A pitfall trap is used to sample small invertebrates on the ground (such as beetles, spiders, etc)

It is done by placing a small pot in a hole in the ground and covering it with something to disguise the trap

It should be checked regularly to avoid animals being eaten and placed in a number of areas to get an accurate representation

Question 9

Paired statement key

Answer 9

A key used to help identify different species

Involves a series of yes/no questions until the species can be identified

“Body has legs?” and then if your answer was yes it could ask “body has more than 7 legs?” but if your answer was no it could ask “body has a shell?”

Question 10

What is an indicator species?

Answer 10

An indicator species tells us about the level of pollution (or about the environment) depending on their presence or absence