biodiversity Flashcards
define biodiversity
the total number of all species and all individuals within those species in a given environment
what factors influence biodiversity
1) human influence
2) succession
3) natural selection
outline how succession influences biodiversity
succession is the change in structure and composition of an ecological community over time.
over time the environment becomes more suitable for other species, therefore they colonise the area, increasing the number of individuals and species therefore increasing biodiversity
what is adaptive radiation
a rapid increase in the number of species with a common ancestor characterised by an increase in biodiversity
outline how natural selection influences biodiversity
mutations create differences in organisms DNA therefore there is variation in phenotype or behaviour
this variation may provide a competitive advantage allowing the organism to outcompete others for resources
they become better suited to the environment and therefore will produce more offspring passing on their advantageous alleles to their offspring
define adaptation
when an organism is specialised to suit the environment they live in
what are the 3 types of adaptations
1) behaviour- refers to actions an organisms does to increase survival and reproduction ie storing food
2) anatomical- refers to physical features which increase survive and reproduction, features which can be observed such as kangaroo rats having increased LOH
3) physiological- refers to internal working which help an organisms reproduce and survive such as birds being able to drink salt water
how is biodiversity assessed
1) physical methods such as quadrats and Simpson’s biodiversity index
2) the number of alleles
3) the proportion of alleles
4) molecular assessment
define polymorphism and how it affects the number of alleles and biodiversity
several different forms of types of individuals among members of a single species which cant be accounted for by mutation alone as a result of polymorphic genes which are genes with more than one allele such as blood type
the more phenotypes possible from a gene the more biodiverse
outline how the proportion of alleles influences biodiversity
refers to the proportion of alleles on one locus, if there is only one allele ie 100% Io blood there is lower biodiversity
if there is 30% Io, 20% IB and 50% IA there is increased biodiversity
outline how DNA finger printing can be used as a molecular assessment of biodiversity
1) the greater the variation in base sequence the greater the genetic biodiversity of the species
2) Not all DNA of organisms codes for proteins and these non-coding pars also undergo mutations so individuals acquire a different base sequence
3) these differences can be seen when comparing the number and position of the bands of a population indicating how similar their DNA sequences are
4) the variations in base sequence can either be SNPs or STRs
what is an SNP
single nucleotide polymorphisms- when there is only one different base
what is an STR
short tandem repeats- when 20-40 base sequences differ and are repeated along introns
