Biodiversity -Module 4 Flashcards
what is biodiversity
-the veriety of living organisms, genetic diversity, and habitats in an area
what is a habitat
a place where an organism lives
what is a species
a group of similar organisms that are capable of breeding to produce fertile offspring
3 levels of biodiversity
- Habitat diversity: (abiotic biotic)
- species diversity: (richness + evenness)
- Genetic diversity: (variation of alleles)
what is an allele
The version of a gene
locus (genes)
The position of the gene on a chromosome
polymorphism
a locus with 2 or more alleles
how is genetic diversity calculated
-genetic polymorphism is used.
-proportion of polymorphic gene loci in a population indicates the level of genetic diversity
-proportion of polymorphic gene loci = no. of polymorphic gene loci/total no. of gene loci
stratified sampling
The population or habitat is divided into subgroups and a sample is taken proportionally to the size of that group
opportunistic sampling
The investigator selects the samples as it is simple to carry out, however it is biased
systematic sampling
Samples are taken at fixed intervals, often along a line. This could be a transect
issues with animal sampling
-animals move
-disturbing habitats- need to trap animals
–cannot trap large animals
what does it mean if the diversity index of the Simpsons diversity index is low
the area may be dominated by one or a few species. environment may be hostile, and only a few organisms are well adapted to it. environmental change may effect the whole habbitat
if the Simpsons diversity index is high:
suggests a number of successful species, a less hostile environment and many ecological niches available. A change to the environment should have less effect on the habitat
how is Human population growth affecting biodiversity
Human population growth
Habitat loss due to the need for more land for housing and food destroys habitats e.g deforestation in amazon decreases habitat & species diversity
Over-exploitation of resources resources used up faster than can be replenished industrial fishing decreasing genetic & species diversity
Urbanisation cities and road developments can isolate species which would then show lower genetic diversity as can’t breed with others of the species
Pollution-> more waste & pollution which can kill species and destroy habitats e.g fertiliser/ gases causing acid rain
Monoculture affecting biodiversity
Monoculture- the growing of a single variety of a single crop
Habitat loss land is cleared to make room for large fields/fish farms
Removal of hedgerows often done to use large machinery and increase space
Loss of local plants and animals often seen as weeds/pests so destroyed using pesticides/herbicides reducing species diversity
Loss of heritage(traditional) varieties of crop-> often don’t make enough money so aren’t planted which reduces species diversity
Climate change
significant long term change in an area’s climate`
how does climate change effect biofiversity
Change in climate can mean that an area becomes inhabitable could decrease biodiversity
Change migration patterns could lead to extinction
what is species richness
no. of different species living in a specific area
species evenness
the number of individuals within the species living in a community
compare biodiversity of an arid desert to a temperate coastline
habitat diversity: desert = low , coastline = high
Species diversity: desert = low, coastline = high
why does genetic diversity increase a species’ chance of long term survival
-examples with a consequence
-Greater genetic variation -therefore more likelihood some organisms suited to habitat change
-examples with a consequence
e.g: some organisms will be better adapted to avoid new predators - therefore less chance of being killed
difference between random and non random sampling
random = organisms have same likelihood of being selected
non random - different organisms have higher/ lower probabilities of being selected
describe how you can increase the likelihood of a sample being a reliable representation of the population as a hole
-use random sampling
-remove sampling bias
-use as large a sample size as possible
-removes the effects of chance
what type of sampling would you use to study how organisms differ throughout the length of a stream
why
systematic sampling
-abiotic conditions vary as you travel downstream affecting the type and abundance of organisms present
what type of sampling would you use to study the distribution of organisms on a school field
why
Random sampling
-environment easy to study / fairly uniform
-reduces sample bias / increases reliability
what is species richness
number of different species living within an area
what is genetic biodiversity
The genetic diversity within a species is the diversity of alleles and genes in the genome of species
what is species evenness
A comparison of the numbers of individuals of each species in a community
