Evolution
List of Definitions:
Species: a group of organisms which are similar in structure and
function and are capable of interbreeding with each other as they
have the same chromosome number.
Population: a group of organisms of the same species living in the
same area at the same time that breed together (there are many
populations within a species)
Evolution: process involving the change in composition of a
population (change in the gene pool) in response to a changing
environment
->occurs slowly
->new types of organisms develop from existing
ones
Natural Selection: the mechanism that favours individuals that
are best suited to the environment
Selective force/pressure: certain environmental factor that is
trigger for determining which individuals are more successful
Gene Pool: total number of all the alleles found amongst all the
breeding individuals in a population
- The greater the variation in the gene pool the fitter and stronger
the population
Gene Frequency: how often a gene occurs in a gene pool
Genetic Diversity/Measure of heterozygosity: a measure of
how many different alleles are present in a population’s gene pool
Biological evolution: process that changes the frequency of
alleles in a population over time
Speciation: process whereby new species develop form existing
species such that they can’t interbreed successfully with the
existing species they rose from
Allopatric Speciation: spatial separation. New species evolve
because two populations are geographically/ physically separated.
This separation is such that these populations can no longer
interbreed ie interrupts gene flow (eg Darwin’s finches)
Sympatric Speciation: genetic isolation. New species develop
where populations that occupy the same geographical area are
prevented from interbreeding by a reproductive barrier
Punctuated equilibrium: evolve rapidly and then stay the same
for a large period of time
Gradualism: Process of slow and constant change
List of Definitions:
Species: a group of organisms which are similar in structure and
function and are capable of interbreeding with each other as they
have the same chromosome number.
Population: a group of organisms of the same species living in the
same area at the same time that breed together (there are many
populations within a species)
Evolution: process involving the change in composition of a
population (change in the gene pool) in response to a changing
environment
->occurs slowly
->new types of organisms develop from existing
ones
Natural Selection: the mechanism that favours individuals that
are best suited to the environment
Selective force/pressure: certain environmental factor that is
trigger for determining which individuals are more successful
Gene Pool: total number of all the alleles found amongst all the
breeding individuals in a population
- The greater the variation in the gene pool the fitter and stronger
the population
Gene Frequency: how often a gene occurs in a gene pool
Genetic Diversity/Measure of heterozygosity: a measure of
how many different alleles are present in a population’s gene pool
Biological evolution: process that changes the frequency of
alleles in a population over time
Speciation: process whereby new species develop form existing
species such that they can’t interbreed successfully with the
existing species they rose from
Allopatric Speciation: spatial separation. New species evolve
because two populations are geographically/ physically separated.
This separation is such that these populations can no longer
interbreed ie interrupts gene flow (eg Darwin’s finches)
Sympatric Speciation: genetic isolation. New species develop
where populations that occupy the same geographical area are
prevented from interbreeding by a reproductive barrier
Punctuated equilibrium: evolve rapidly and then stay the same
for a large period of time
Gradualism: Process of slow and constant change
