biodiversity, ecosystems and taxonomy

define biodiversity

the variety of living organisms, there genes, species and habitats in a particular area

what 3 ways can biodiversity be measured in?

species diversity, genetic diversity, ecosystem diversity

how can we preserve biodiversity in agricultural settings?

use hedgrerows instead of fences, growing different crops in the same area, reduce the use of herbicides and pesticides, preserve wetlands

define inter specific variation

the differences BETWEEN species

define intraspecific variation

differences between individuals of the SAME species

define conservation

the maintenance of ecosystems and biodiversity by human in order to preserve the Earths resources

what is directional selection

Favours individuals that have extreme phenotypes left or right of the mean (which is selected against)

what is ecosystem diversity

a measure of the range of different habitats in a particular area

what is genetic diversity

number of different alleles in a population

what is index of diversity

describes the relationship between the number of different species AND the abundance of individuals in each species within a community

what is phylogenetic classification

organisms grouped based off of evolutionary relationships

define species richness

a measure of the number of DIFFERENT SPECIES in a community at a given time.

what is stabilising selection

favours individuals with traits close to the mean and selects against the extremes

what is standard deviation

a measure of the width of a normal distribution curve and an indication of the range of values

explain allopatric speciation

two populations of the same species become geographically isolated from each other and due to the different selection pressures and environments, adapt to each unique environment and become so different they can no longer interbreed with each other to produce fertile offspring

define variation

The differences between individuals due to genes, the environment or a combination of both

what is a climax community

the stable community of organisms that exists at the final stage of ecological succession

define community

all of the populations of different species living together in a habitat

what is disruptive selection

Favours both the extreme phenotypes

what is genetic drift

variations in allele frequencies in small populations due to CHANCE

what does the hardy weinberg principle predict

that the ration of dominant and recessive alleles in a population will remain constant between generations if correct conditions are met

what is a pioneer species

species that can survive in hostile environments and colonise bare rock and sand

explain sympatric speciation

when two populations within the same area become reproductively isolated