Biodiversity Flashcards
What is biodiversity and why is it important?
The variety if living organisms present in an area
It is essential in maintaining a balanced ecosystem for all organisms as they are all interconnected (rely on each other)
What is habitat biodiversity?
The number of different habitats found within an area
What is species diversity?
Species richness- the number of different species living in a particular area
Species evenness- a comparison of the numbers of individuals of each species living in a community
What is genetic biodiversity and why is it important?
The variety of genes and alleles that make up a species
Greater genetic biodiversity- better adaptation to a changing environment, eg resistance to disease, less likely to become extinct
What can sampling be used to measure?
The abundance of an organism or measuring a particular characteristic of an organism
What is random sampling?
Selecting individuals by chance
Mark a grid out using two tape measures laid at right angles to one another
Use a random number generator to generate random co ordinates
Take a sample at the coordinate generated
What are the types of non random sampling?
Opportunistic- use organisms that are conveniently available (not representative of the population)
Stratified- population is divided into sub groups based on a particular characteristic then a random sample is taken from each of these strata (proportional to size)
Systematic- Using a line or belt transect to monitor changes over a habitat
Why is a sample never entirely reliable/ representative of organisms present in a habitat?
Sampling bias- minimised by using random sampling
Chance- minimised by using a large sample size
Identification keys should be used
What is capture-mark-release recapture?
Used to estimate animal population size
Capture as many individuals of a species in an area, mark them ans then release them back into the environment. Allow time for organisms to redistribute themselves and collect another sample. Compare the number of marked individuals with the number of unmarked.
Why is it important to conserve areas with low species diversity?
Organisms present in those habitats can be highly adapted to the extreme and may not be able to survive elsewhere
Factors that reduce genetic diversity
Selective breeding
Captive breeding
Natural selection
Genetic bottlenecks- when only a few individuals within a population survive an event or change thus reducing the gene pool (only the alleles of the surviving members are available to be passed on to offspring)
The founder effect- small number of individuals create a new colony
Rare breeds
Factors that increase genetic diversity
Mutations in the DNA
Gene flow- when an individual migrates from one population and breeds with a member of a different population
How is genetic diversity measured?
By measuring the number of polymorphic gene loci
Factors affecting genetic biodiversity
Deforestation to create space for buildings and infrastructure- removes habitat, breeding sites and camouflage for species, increases Co2 levels in the environment
Selective breeding- organisms bred for particular characteristics- smaller gene pools and little genetic variation so the species is more vulnerable to disease
Monoculture- eg removal of hedgerows to plant fields of the same crop, removing habitat of many organisms
Use of pesticides/ herbicides-
Global warming- eg melting of the polar ice caps leads to a destruction of habitat and rising sea levels, xerophytes could become more dominant, insect life cycles change eg more spread of disease carrying vectors
Reasons for maintaining biodiversity- aesthetic
Enriches our lives, may inspire people or make diseased people heal quicker
