Evolution Flashcards
What is evolution
The process which living things change over many generations which is a result of changes to the genome
What is natural selection
The non random increase in frequency of DNA sequences that increase survival and the non random reduction in the frequency of deleterious sequences
What are deleterious sequences
A deleterious sequence is a harmful mutation which negatively effects an organisms survival chances.
What is stabilising selection
An average phenotype is selected for and extremes of the phenotype range are selected against
What is directional selection
One extreme of the phenotype range is selected for
What is disruptive selection
Two or more phenotypes are selected for
What is horizontal gene transfer
Genes are transferred between individuals in the same generation
What is vertical gene transfer
Genes are transferred from parent to offspring as a result of sexual or asexual reproduction
What is gene transfer
Prokaryotes such as bacteria can exchange genetic information through horizontal gene transfer. These results in much faster evolutionary change than in organisms which use vertical gene transfer
What is species
A group of organisms capable of interbreeding and producing fertile offspring and which do not normally breed with other groups
Speciation
The generation of new biological species by evolution as a result of isolation mutation and selection
What are the types of isolation barriers
Geographical
Ecological
Behaviour
What is allopathic speciation
When new species arise due to isolation of a population by geographical barriers like rivers or mountains which isolate animals and plants
What is sympatric speciation
When new species arise despite occupying the same geographical area isolation barriers in this type of speciation can be ecological.
