Unit one Key Area seven Flashcards
Form a selection that results in a population being split into two distinct groups, each with its own mean value for a trait.
Disruptive
Form a selection that leads to a reduction in genetic diversity without a change in a population’s mean value or trait.
Stabilising
Form a selection that results in a progressive shift in a population’s mean value for a trait.
Directional
Non-random increase in frequency of DNA sequences which confer an advantage and increase the chance of survival.
Natural selection
Transfer of genetic sequences from one generation ‘down’ the the next by sexual or asexual reproduction.
Vertical Inheritance
Transfer of genetic material ‘sideways’ between contemporary members of a population.
Horizontal inheritance
Benefit gained by mutant organisms in an environment that suits them but not other members of the population.
Selective Advantage
Process of gradual change in a population of organisms over successive generations resulting from genomic variations.
Evolution
Geographical, ecological or behavioural barrier that prevents genetic exchange between populations of a species.
Isolating mechanism
Form of speciation where gene flow between populations of a species is prevented by a behavioural or ecological barrier.
Sympatric
Generation of new biological species by evolution as a result of isolation, mutation and selection.
Speciation
Group of organisms that produce fertile offspring and share the same chromosome complement.
Species
Total of all the genomic sequences (alleles) present in the genotypes of the members of a species.
Gene Pool
Form of speciation where gene flow between populations of a species is prevented by a geographical barrier
Allopatric
