4.2.1 Biodiversity Flashcards
What are the three types of biodiversity?
Species
Habitat
Genetic
Define biodiversity.
The study of all variation that exists between all forms of life.
Define habitat diversity.
The range of different ecosystems or habitats within a particular area or region.
If there are a large number of different habitats within an area, will it be classed as having high or low biodiversity?
High
If there are only one or two habitats within an area, is the area likely to have high or low biodiversity?
Low
What does species diversity mean?.
An ecosystem that has a high number of different species would be described as being species-rich.
Explain species diversity.
The greater the number of species in an ecosystem, and the more evenly distributed the number of individuals from each species, the greater the species diversity.
Define genetic diversity.
The diversity of the alleles and genes in the genome of a species.
Why is it difficult to measure the levels of biodiversity in an ecosystem?
This requires the identification and cataloguing of all organisms which is possible for smaller areas however for larger and more complex ecosystems, it is impossible to find, identify and count every organism that lives there.
What does sampling measure?
The abundance and distribution of species and populations.
What are the two types of sampling?
Random
Non-random
When would we use random sampling?
Ecosystems are very complex with large numbers of different species of different sizes so random sampling if often used to estimate the distribution and abundance of species.
Define species distribution.
How the spcies is spread throughout the ecosystem.
Define abundance.
The number of individuals in that species.
Benefit of random sampling.
The position of the sampling points is completely random so there will be no bias by the person who is taking the sample.
What is a quadrat?
Square frame of wood or wire that can be a variety of sizes, they are placed on the ground and organisms within them are recorded.
Why would you use a quadrat?
They can be used to measure the distribution and abundance of plants or slow-moving organisms.
List some examples of random sampling methods that can be used for mobile animals.
-Sweeping nets
-Pitfall traps
-Pooters
-Tullgren funnels
-Kick-sampling
What are sweeping nets
A sweeping net is a large, string net which is used to catch flying insects or insects that live in long grass. It works by sweeping the net back and forth.
What is a pitfall trap?
A pitfall trp is a can or jar which is buried into the ground and used to catch ground-dwelling insects as they fall into the trap.
What is a pooter?
A pooter is a small plastic or glass container with two tubes sticking out that are used to suck up small insects.
One tube is placed over the insect and the second is used by the scientist to create suction.
What is a tullgren funnel?
These are funnels with a light bulb above and a container below that are used to collect invertbrates that live in soil. The soil is placed into the funnel and the light and heat force it to move down and drop into the container.
What is kick-sampling?
The scientist uses their foot to churn up the stream bed and the invertebrates are carried into the net.
When is kick-sampling used?
This technique is used to catch freshwater invertebrates living in streams or rivers.
What is non-random sampling?
The positions of sampling points are chosen.
Limitation of non-random sampling.
Bias could be shown- individuals may deliberately place quadrats in areas with the least species as they will be easier to count.
What are the three main types of non-random sampling.
Opportunist
Stratified
Systematic.
What is opportunist sampling?
This involves picking and choosing sampling locations based on many non-random factors.
E.g on a school trip children may be asked to take samples only from areas that are safe.
What is stratified sampling?
This involves matching the number of sampling locations with the proportion of area that habitat covers in the whole area being studied.
What is systematic sampling?
Different areas of a habitat are identified or sampled separately.
Why would we use a transect?
Helps to show how species distribution changes with changing physical conditions.
Two types of transect.
Belt
Line
What is a line transect?
Lay out a measuring tape in a straight line across the sample area and at equal distances along the tape record the identity of the organisms which touch the line.