4.2 biodiversity Flashcards
What is biodiversity?
a measure of the variation found in the living world
define habitat biodiversity
The range of habitats in which different species live
define species biodiversity
the range of organisms found in a habitat
define species
a group of organisms which can freely interbreed to produce fertile offspring
define genetic biodiversity
variation between individuals belonging to the same species, can create breeds
define sampling
selecting a small portion and studying that carefully
how is random sampling carried out
sample sites are randomly selected such as through random generation of coordinates
advantage of random sampling
ensures data isn’t biased through selective sampling
disadvantage of random sampling
may not cover all areas of habitat equally and can lead to underestimate of biodiversity
types of non-random sampling
Opportunistic, stratified, systematic.
how is opportunistic sampling carried out
researcher makes sampling decisions based on prior knowledge or during the process of collecting data
advantage of opportunistic sampling
Easier and quicker than random sampling
disadvantage of opportunistic sampling
data may be biased- can lead to overestimate of biodiversity
how is stratified sampling carried out
dividing a habitat into areas which appear different and sampling each area separately
advantage of stratified sampling
ensures all different areas of a habitat are sampled and species are not under represented
disadvantage of stratified sampling
may lead to overrepresentation of some areas
how is systematic sampling carried out
samples are taken at fixed intervals across the habitat
types of systematic sampling techniques
line transects and belt transects
advantage of systematic sampling
useful when a habitat shows a clear gradient in some environmental factor
disadvantages of systematic sampling
only species on the line or within the belt can be recorded, some may be missed and lead to underestimate of biodiversity
what preparation should be considered when sampling a habitat
suitable clothing and footwear
apparatus needed to carry out sampling
clipboard pen and paper to record observations
appropriate keys to identify plants
camera to record specimens and grid location
what is best to do when measuring biodiversity
use a range of sampling techniques- can be important if the habitat is not homogenous (even)
what is an important aspect to consider when sampling a habitat
the effect your presence will have on the habitat- sampling should cause as little disturbance as possible
what is the best way to count plants which are too small or there’s numerous
calculate a value of percentage ground cover occupied by each species
define quadrat
square frame used to define the size of a sample area
how may you use a quadrat with random sampling
generate random numbers then use them as coordinates to place the quadrats within the habitat
what can help with placing a quadrat accurately
a tape measure
what do you need to do inside the quadrat
identify the plants found and then calculate the percentage cover as a measure of their abundance
what do some quadrats have to make estimates more accurate
a grid of string that divides the quadrat into a number of smaller squares
what can you use to measure percentage cover
a point frame
what is a point frame and how do you use it
a frame holding a number of long needles
lower the frame into the quadrat and record any plants touching the needles
what should you not forget to record when using a quadrat and why
bare ground as its easy to bias your readings by using the point frame not randomly within the quadrat
what is the best way to use a point frame
at regular intervals across the quadrat
what is a transect and how do you use it
a line taken across the habitat
stretch a long string across the habitat and take samples along the line
what would you record with a line transect and where would you use it
the plants touching the line at set intervals along it
in a large habitat
define interrupted belt transect
Quadrat placed at regular intervals along the line
what does an interrupted belt transect provide
quantitive data at intervals across the habitat
define continuous belt transect
placing a quadrat beside the line and moving it along the line so you can study a band or belt in detail