4.2 - Biodiversity Flashcards
(23 cards)
What is biodiversity?
The spread of organisms and species in a particular habitat
What is species evenness?
The proportion of each species there is in an area
What is species richness?
How many different species there are in area
What is a transect and why do you use it?
A line across a habitat used to measure the change of concentrations of species e.g. to investigate the influence of a factor
How do you use a transect?
Take measurements every n metres down the line
What is a quadrat and how do you use it?
A square grid - place in a location and count percentage cover of a species
What are the sampling methods?
Random
Stratified
Systematic
What is random sampling?
When you take a random number generator to get two coordinates along two axes.
What is systematic sampling?
When you take measurements n metres along a transect
What is stratified sampling?
When a habitat is divided into different areas e.g. wooded, grassy and samples are taken here
What is simpsons biodiversity index?
A calculation done in order to establish the biodiversity of a habitat - the closer the number is to one, the higher the diversity
Chi squared test?
Compared the expected number of species with the actual number e.g. to establish the decline or incline of birth rates
What affects biodiversity?
Alter ecosystems
Destroy and fragments species
Pollute atmosphere
Agriculture
What is extinction?
When the last living member of a species ceases to exist
Why did this change?
Because many of the organisms in the kingdoms had both animal and plant characterised e.g. fungi and so could not be classified
How do you sample animals?
Sweep net technique sweeps up small insects, overturn onto a white sheet
What is opportunistic sampling?
When the quadrat is placed to give the largest population density
Ecological reasons to maintain biodiversity?
The presence of a keystone species can cause the ecosystem to collapse if removed, also they can provide natural solutions to our problems
Economic reasons to maintain biodiversity?
Retention and purification of fresh water Medicine Recycling of nutrients Recycling of waste Natural resources
Human aspects that threaten biodiversity?
Pollution
Exploitation of natural resources
Fragmentation of habitats
Alteration of ecosystems
How does agriculture threaten biodiversity?
Over farming causes soil erosion Removal of nutrients from soil Monoculture Fragmentation of habitats Pesticides/insecticides
What is conservation in situ?
Maintenance of the biodiversity/ habitat/ species in its natural habitat
Conservation ex situ?
Preservation of a species outside its natural habitat