4.2 biodiversity Flashcards
what is habitat biodiversity
refers to the number of different habitats found in a certain area
how does the number of habitats effect the biodiversity
Each habitat can support different number of species.
Therefore, the greater the habitat biodiversity the greater the species biodiversity
what is species biodiversity
is the number of species & individuals within each species in a community.
what are the 2 different components of species biodiversity
Species Richness
Species Everness
what is species richness & how to find it
Species Richness is the number of different species in a particular area at a particular time. To measure you would record the number of different species that are present. The investigator would also have identification keys.
what is species everness & how to find it
species evenness is the comparison of the numbers of individuals of each species living in a community and whether it’s evenly distributed. To measure you would record the number of individuals present for each species identified.
what is genetic biodiversity
Genetic Biodiversity refers to the variety of genes amongst all the individuals in a population of one species.
why is genetic biodiversity useful
Greater the genetic biodiversity within a species allows for better adaptation to a changing environment and is more likely to result in individuals who are resistant to disease
what is sampling used for
Sampling can be used to estimate the number of organisms in an area without having to count them all
what 2 things must you do to ensure that sample is represensative
Take a large sample: You can calculate a mean & statistical test to see if any differences or correlations you see are significant
Random Sampling: To ensure there is no bias
random sampling description (3)
Selecting individuals by chance
Everyone in the population has an equal chance of selection
To decide which organism to study random number tables or computers can be used & you should not be involved on deciding
what is opportunity sampling & why is it weak
Involves sampling organism which are conveniently available and therefore involves bias
Doesn’t accurately represent population
stratified sampling & example to the different strata
Some populations or habitats can be separated into groups to sample from
For example, when sampling a pond, you may split the bond into 3 regions (surface, shallow, and deep-water regions). You would then take random samples with each group (strata)
what is systematic sampling
Involves identifying different areas within a habitat to sample which are then samples separately
when is systematic used
to measure distribution in different regions to see if it has effect on biodiversity
what 2 techniques are used to carry out sampling
Line Transect
Belt Transect
describe line transect
This involves marking a line along the ground between 2 poles and taking samples at specified points. This can include describing all the organisms which touch the line or distance of samples from the line.
what is belt transect
This involves placing a single tape measure along sample area and at regular set distances along the tape measure you would place a quadrat and record data
what are 2 biases that must be taken into consideration when taking sample
Sample Bias
Chance bias
what is sample bias
The selection process may be biased. This may be by accident or may occur deliberately. For example, you may choose to some point particular area that has more flowers because it looks interesting. The effects of sampling bias can be reduced using random sampling where human involvement in choosing the sample is removed.
what is chance bias
The organisms selected by chance may not be representative of the whole population. For example, a sample of five ones collected in a trap may be the five longest in the habitat. Chance can never be removed completely from the process, but its effect can be minimised by using a larger sample size. The greater the number of individuals studied, the lower the probability that transferred influenced the result. Therefore, the larger sample size would be more reliable.