KA3.2 - Distribution of Organisms Flashcards
Describe the purpose of sampling?
to allow for an estimate to be made of the number of a specific species in an area.
State two benefits of sampling?
Sampling saves time and is easier than counting every organisms in an area.
A quadrat is used to sample … or …
Slow moving or immobile organisms.
If quadrat sampling is unreliable, how can this be fixed?
By taking more samples (repeating the sampling). The more samples you take the more reliable (trustworthy) your results are.
Explain the reason why representative sampling is very important.
- If not enough samples are taken (i.e. only one) then you cannot accurately estimate the abundance of organisms in the area.
- Also, if the quadrat is placed in specific areas this can cause bias and make your results not representative of the full area.
Small living organisms (insects) are sampled using a …
Pitfall trap.
What is one error to avoid in setting up a pitfall trap?
The trap must be level with the soil so insects can fall in.
How would you answer a “describe the trend” question?
Describe the graph or table by linking the two variables together. As the independent variable (thing being changed) increases/decreases the dependent variable (thing being measured) increases/decreases/stays the same.
List at least three biotic factors.
- Competition for resources
- Disease
- Food availability
- Grazing intensity
- Predation.
What are at least three abiotic factors?
- Light intensity
- Moisture
- pH
- Temperature
A light meter is used to measure …
Light intensity
Soil moisture is measured using a …
Soil moisture meter
A pH meter measures …
pH
When using a soil moisture or pH meter the probe must be … between samples to prevent the previous sample impacting the results
Cleaned.
Describe some errors to avoid when using a light meter?
Avoid shading the light meter and point the light meter at the source of light.
