Biodviersity Flashcards
What does Biodiversity mean
A measure of variation found in the living world
What is a habitat
Where an organism lives
What is the definition of a species
A group of organisms that can interbreed to produce fertile offspring
What levels are biodiversity considered at and explain what they mean
Habitat - The range of different habitats in an ecosystem
Species - Related to species richness and species evenness
Genetic - Variation within a species. For example the number of different alleles within the population
Why do we take samples to measure biodiversity
It can be time consuming to measure the whole area so usually smaller samples are taken then scaled up so they are representative of the population
What is species richness and evenness
Richness - the number of species in an area
Eveness - the proportion/abundance of each species in an area
What are the types of sampling
Random - randomly generating coordinates
Non random - opportunistic - Taking samples based on previous knowledge. This is much
easier and quicker but data will likely be biased
systematic - Taking samples usually when land isn’t evenly distributes line or
belt transect can be used. Species may be missed leading to an
underestimate of biodiversity
stratified - dividing a habitat into areas that appear different. This ensures
areas aren’t underrepresented
How can you improve your sampling techniques and what techniques can be used to sample
Use a key
Take repeats at different times of the year
Take percentage cover
Calculate mean density
use Abundant
Common
Frequent
Occasional
RareHow can you sample larger animals
Sweep nets - For insects in long grass or winged insects such as butterflies
Pooters - Suck insects up, usually from a bark of a tree
Tullgren funnel - A light drives animals down as litter dries out
Pitfall trap - Trap to catch small animals
Capture recapture technique (c1*c2)/marked individuals on c2
What is an Allele Locus Polymorphic gene locus Simpsons index
Version of a gene
Position of that gene on a chromosome
A locus that has more than two alleles
A measure of the diversity of a habitat
What is the formula for Simpsons Index
𝐷 = 1 - Ʃ (n/N)^2
What does a high and a low Simpsons index mean
There is high biodiversity, complex food webs many niches habitat is more likely to survive if there was a change in environment
There is a low biodiversity, simple food webs , more specific adaptation. The habitat is dominated by one of two species and would less likely be able to adapt and survive if there was a change in the environment
How can we calculate genetic diversity
You can look at the proportion of polymorphic loci compared to the total loci
How has human population growth affected biodiversity
Human population is growing exponentially so there’s more demand for houses and food. This has led to destruction of habitats , deforestation, pollution of the atmosphere. We alter ecosystems to provide ourselves with food
How has agriculture and selective breeding affected biodiversity
We clear natural vegetation reducing habitat size and genetic diversity. Modern agriculture relies upon monoculture and selective breeding to increase efficiency. This limits genetic diversity. With the same crops being grown soil erosion arises and lack of nutrients also appear. This is because the same minerals are always taken and organic matter is not replaced
Farmers pick particular traits when breeding this leads to loss of alleles that could be important in the future. Lack of genetic diversity leaves animals susceptible to diseases and extinction of species
