Flashcards in 4.2- Biodiversity Deck (49)
What is the definition of biodiversity?
The variety of living organisms in an area
What is the definition of a species?
A group of similar organisms are able to reproduce to get fertile offspring
What is the definition of a habitat?
An area inhabited by species. It includes the abiotic factors and biotic factors
What are the three different levels of biodiversity can be considered on?
What is the definition of habitat diversity?
The number of different habitats in an area
What is the definition of species diversity?
The number of different species (species richness) and the abundance of each species (species evenness) in an area
What is the definition of genetic diversity?
The variation of alleles within a species
What are the different types of a non-random sampling?
Why should samples be taken at random?
To avoid bias in your results
What is the definition of systematic sampling?
When samples are taken at fixed intervals
What is the definition of opportunistic sampling?
When samples are chosen by the investigator
It is simple to carry out but the data will be biased
What is the definition of stratified sampling?
When different areas in a habitat are identified and sampled separately in proportion to the habitat of a whole
Why is it sometimes necessary to take a non-random sample?
Eg. When there's lots of variety in the distribution and you want to make sure all the different areas are sampled
What is species richness?
The number of different species in an area
What is species evenness?
A measure of the relative abundance of each species in an area
If a habitat has a great species richness and a high species evenness, what will happen to the biodiversity?
It will be high
How is biodiversity measured?
Using the Simpsons index of diversity
What is the formula for the simpsons index of diversity?
D=1-(sum of(Total number of individuals of 1 species/Total number of organisms of all species)^2)
A habitat has a simpsons index of diversity equal to 0. What does this mean?
It is not very diverse
A habitat has a The Simpsons index of diversity equal to 1. What does this mean?
It is very diverse
What could occur if a population has a low genetic diversity?
They might not be able to adapt to change in the environment in the whole population could be wiped out buy disease
What does polymorphism describe?
A locus that has two or more alleles
What are the three main factors that affect global biodiversity?
Human population growth
Increased use of monoculture in agriculture
How does human population growth decrease biodiversity?
Overexploitation- greater demand for resources
Urbanisation can isolate species
Pollution can destroy habitats
How does increased use of monoculture in agriculture decrease biodiversity?
Habitat are lost as land is cleared
Plants destroyed with pesticides
Varieties of crops that don't make enough money and not planted anymore
How does climate change affect biodiversity?
A changing climate can increase or decrease the habitable areas of some species (this can increase or decrease biodiversity)
Species may be forced to migrate which shuffles biodiversity around (species can even go extinct)
Why is maintaining biodiversity important? (ecological reasons)
To protect species, including keystone species
To maintain genetic resources
Why is it important to protect species, including keystone species?
Organisms in an ecosystem are interdependent
The loss of just one species can cause disruption of food chains and disruption of the nutrient Cycle
What's a keystone species?
Species which many other species in an ecosystem depend on and without them, the system will change dramatically
They can be Predators modifiers or hosts