Mutations
A sudden and random change in a gene or chromosome leading to new characteristics in an organism. Occurs purely by chance.
What is a mutation
The individual has three of chromosome 21
What is Downs syndrome
High birth rate and limited resources, leads to some individuals surviving and some dying.
What is Struggle for existence
Random, non-directional change in allele frequency between generations. Occurs purely by chance.
What is Random genetic drift
Alternative forms of a particular gene. Individuals inherit one from the mother and one from the father.
What is an allele
A gene mutation where only one base of the DNA is affected.
What is a point mutation
An individual is missing a chromosome
What is monosomy
Any factor that causes the death of organisms with certain characteristics, but which has no effect on individuals without those characteristics
What is selective agent
Occurs when a small group moves away from its homeland to a totally new area and establishes a population, which later expands
What is the founder effect
The sum of all alleles in a given population.
What is a gene pool
An organism with a characteristic resulting from a mutation.
What is a mutant
A gene mutation on chromosome 7, causes salty tasting skin and persistent coughing
What is cystic fibrosis
organisms with favourable characteristics survived, while many of those with unfavourable characteristics died before they had an opportunity to reproduce and pass on the trait.
What is Survival of the fittest
An event, such as a natural disaster, severely reduces the size of the population. Allele frequencies of the new, smaller population may be different to the population before the event
What is the Bottleneck effect
economic status, educational background and social position
What is sociocultural barriers
Bases are added or removed, affecting the series of three bases that code for an amino acid. It affects the outcome of the whole DNA.
What is a frameshift mutation
Red blood cells become crescent shaped only in low oxygen environments
What is sickle cell trait
The differences that exist between individuals or populations of a species
What is variation
the movement of genetic material from one population to another.
What is gene flow
The movement of people from one area to another with the intention of settling permanently
What is migration
part of a chromosome breaks off and is rejoined to the wrong chromosome
What is translocation
Individuals with a disease trait are favoured, as they don’t exhibit the disease, but they are also resistant to other diseases.
What is heterozygous advantage
all living organisms reproduce at a rate far greater than that at which their food supply and other resources increase
What is birth rate
A population where the incidence of Tay- sachs disease is 1 in 27 people
What is Ashkenazi Jew
A mutation that causes a change in an amino acid resulting in a different protein being produced
What is a missense mutation