4.2.1 biodiversity Flashcards
(26 cards)
define biodiversity
measure of variation found within living world
define habitat
where an organism lives
define species
group of organisms which can freely interbreed to produce fertile offspring
habitat biodiversity
place where individual species live & the range of habitats in which different species live
- each habitat will be occupied by range of organisms
describe species biodiversity
species = individual organisms which are very similar in appearance, anatomy, physiology, biochemistry & genetics
- can interbreed freely to produce fertile offspring
- range of organisms found in a habitat contribute to species biodiversity
- 2 habitats may have equal number of species but may not be considered equally diverse
types of species biodiversity
- species richness
- species evenness
species richness
number of species
species evenness
degree to which the species are represented
describe genetic biodiversity
- variation between individuals belonging to the same species
- ensures we don’t all look identical
- can create breeds within a species
what is required to measure the biodiversity of a habitat
- observe all species present
- identify species
- count how many individuals of each species
what is sampling a habitat
select small portion & study it
–> can multiply up numbers of individuals found to estimate number in whole habitat
what must the samples be
representative of the habitat
name 2 main sampling techniques
- random
- non-random
what is non-random sampling split into
- opportunistic
- stratified
- systematic
how is random sampling carried out
sample sites in habitat randomly selected:
- can be achieved by using randomly generated numbers as coordinates
OR
- selecting coordinates on map & using portable global positioning satellite system to find exact position in habitat
advantages of random sampling
- ensures data isn’t bias by selective sampling
disadvantages of random sampling
- may not cover all areas equally
- species of low presence may be missed = underestimate of biodiversity
how is (non-random sampling) opportunistic sampling carried out
- researcher makes sampling decisions based on prior knowledge or during process of collecting data
- researcher may deliberately sample area they know/can see contains a particular species
advantages of (non-random sampling) opportunistic sampling
- easier & quicker than random sampling
disadvantages of (non-random sampling) opportunistic sampling
- data may be biased
- presence of large/colourful species may make researcher want to include the species = may lead to overestimate of importance (thus, overestimate of biodiversity)
how is (non-random sampling) stratified sampling carried out
- divide habitat into areas which appear different
- sample each area separately
eg. patches of bracken in heathland sampled separately from heather/gorse patches
advantages of (non-random sampling) stratified sampling
- ensures all different areas of habitat are sampled
- ensures species aren’t under-represented due to possibility that random sampling misses certain areas
disadvantages of (non-random sampling) stratified sampling
- possibility it will lead to over-representation of some areas in sample eg. disproportionate number of samples taken in small areas which look different
how is (non-random sampling) systematic sampling carried out
- samples taken at fixed intervals across habitat
- line transects/belt transects are systematic techniques
