biodiv Flashcards
(29 cards)
what is a species
a group of organisms which can freely interbreed to produce fertile offspring
what is a habitat
where an organism lives
what are the three types of biodiversity
Genetic biodiversity
Habitat biodiversity
Species biodiversity
what is species richness
the number of different species in an area or habitat
what is species eveness
the distribution of individuals among different species in a specific habitat or area
what is genetic biodiversity
variation of genes between individuals belonging to the same species
genetic variation ensures we dont all look identical
what does genetic variation play a crucial role in
Genetic variation is crucial for a species as it enables adaptation of a species to its changing environment.
allows natural selection
allows camoflage to protect species from predators
what is random sampling
Sample sites are taken inside the habitat.
you decide where to take the sample sites before-hand- can be achieved by a random number generator for coordinates.
what are the advantages of random sampling
ensures data isnt biased
what are the disadvantages of random sampling
it might not cover all areas of the habitat equally- species with a low biodiv can be missed, leading to an underestimate of biodiv
what is non random- opportunistic sampling
the researcher uses prior knowledge to make sampling decisions.
e.g sampling a specific area they know a particular species lives
what are the three types of non random sampling
opportunistic
stratified
systematic
what is non random systematic sampling
when samples are placed in fixed intervals along a habitat
e.g belt transect or line transect
what is non random stratified sampling
dividing a habitat into areas which appear different and sampling them separately.
e.g. grass near water, grass on a hill.
what is the difference between random or non random sampling
Random sampling is chosen randomly is an unbiased representation of the total population.
Non-random sampling is where the sample selection is based on factors other than just random chance.
what are the advantages to the non random systematic sampling
useful when a habitat shows a clear gradient in environmental factors. For example, water getting drier further from the pond.
what are the disadvantages of non random systematic sampling
can miss species outside of the belt leading to underestimation of biodiversity
what are the advantages of non random stratified sampling
ensure all different areas of habitat are sampled and species aren’t underestimated- because random sampling may miss areas.
what are the disadvantages of non random stratified sampling
may lead to over representation of some areas in the sample.
what is the advantages and disadvantages of non random opportunistic sampling
Advantages- easier and quicker than random sampling
Disadvantages- data may be biased and cause overestimate, as bigger species can entice the researcher to include it in the study.
what are disadvantages of random sampling
the person choosing could show bias towards or against certain areas
Individuals can purposefully place the quadrats in areas with the least species as these will be easier and quicker to count
This is unrepresentative of the whole area
what is a keystone species
a species which helps hold the ecosystem together.
.other species rely on them
.they have a significant effect on the ecosystems (taken from mark scheme)
what is a felled tree
a cut down tree
how can increased habitat diversity cause increased species and genetic diversity
more habitats means
more species to live in new habitats. (species)
genetic diversity will rise as more habitats means more conditions in which the animals will live in (genetic)
