Chapter 11.3 Flashcards
(21 cards)
Why do you use more than one sampling technique?
So a range of data can be collected
What are the type of ways that you can sample animals?
Pooter Sweep Nets Pitfall traps Tree beating Kick sampling
How do you carry out “potter” sampling?
To catch insects - you suck through mouthpiece and insects are drawn into holding chamber via inlet tube
A filter is place near the mouthpiece to prevent them getting sucked into the mouth
How do you use a “sweep nets” for sampling?
Can be used to catch insects in areas of long grass
How do you use a “pitfall traps” for sampling?
{can be used to catch beetles and spiders
A hole is dug in the ground which insects fall into (the hole being deep enough that they cannot crawl out and covered with a root structure propped up so that it doesn’t fill with rainwater)
Trap is left overnight so nocturnal species is sampled
How do you use “tree beating” for sampling?
{For invertebrates living in trees or bushes}
A large white cloth is stretched out under a tree
The tree is then shaken or beaten so invertebrates are dislodged
The animals will fall onto the sheet where they are collected and studied
How do you carry out “kick sampling” for sampling?
{Used to study organisms in the river}
The river bank bed is kicked for a period of time to disturb the substance
A net is held downstream for a set period of time in order to capture any organisms released into the flowing water
What is a qudrat?
A piece equipment that is used to sample plants and used to pinpoint an area which the sample plant should be collected
What are the two types of quadrats?
Point quadrat
Frame quadrat
How is a “point quadrat” done?
It consists a frame containing a horizontal bar
At set intervals along the bar, long pins are pushed through bar to reach the ground. Each species of plant the pin touches is recorded.
How is a “frame quadrat” done?
This is when a square frame is divided into a grid of equal sections
The type and number of species within each section of the quadrat is recorded
How should quadrats be used to for most valid representation?
They should be used in a random sampling technique
How should quadrats be used to investigate distribution and presence?
Quadrats should be placed systematically along a line or belt transect
What is species richness?
Measure of the number of different species living in a specific area.
What is species evenness?
Refers to how close in numbers the populations of each species in an environment are
What are the 3 main ways that you can use a frame quadrat can be used to sample the population of plants living a habitat?
Using the density - gives you an absolute measure
Measuring the frequency - gives you an estimate
Measuring the percentage cover - gives you an estimate
How can you measure the “density” the quadrats?
If the specie is seen clearly, you then count the number of them in a 1m by 1m square quadrat (giving you density per square metre)
How can you measure the “frequency” the quadrats? When is it used?
{used in situations where individuals of species is very hard to count}
To do this, you use a small grid within a quadrat and you then count the number of squares with particular species present ( so if 65 quadrats out of 100 have that species =65%)
How can you measure “percentage cover” using quadrats? when is it used?
{when loads of data needs to be collected quickly}
When a species is difficult to count - an estimate by the eye of the area with the quadrat that a particular plant species covered
What are the types of abiotic factors? How do you measure each factor?
Wind speed - anemometer - ms-1
light intensity - light meter - lx
relative humidity - humidity sensor - mg dm-3
pH - pH probe - oC
oxygen content in water - dissolved oxygen probe - mg dm-3
What are the advantages of using sensors to measure abiotic factors?
- Rapid changes can be detected
- Human error in taking a reading is reduced
- A high degree of precision can often be achieved
- Data can be stored and tracked on the computer
