1.7 - Evolution Flashcards
What is Evolution?
The changes in organisms over generations as a result of genomic variation
What is Natural Selection?
The non-random increase in the frequency of DNA sequences increases survival and the non-random reduction in the frequency of deleterious sequences
What happens as a result of changing phenotype frequency?
Stabilising, Directional and Disruptive selection
What happens in Stabilising selection?
In stabilising selection, an average phenotype is selected for and extremes of the phenotype range are selected against
What happens in Directional selection?
In directional selection, only one extreme of the phenotype range is selected for
What happens in Disruptive selection?
In disruptive selection, two or more phenotypes are selected for
What is Horizontal gene transfer?
Horizontal gene transfer is where genes are transferred between individuals in the same generation
What is Vertical gene transfer?
Vertical gene transfer is where genes are transferred from parent to offspring as a result of sexual or asexual reproduction
Is Natural selection quicker in Prokaryotes or Eukaryotes?
Natural selection is more rapid in Prokaryotes
Why is Natural selection quicker is Prokaryotes?
Prokaryotes can exchange genetic material horizontally, resulting in faster evolutionary change than in organisms that only use vertical transfer
What is Speciation?
Speciation is the generation of new biological species by evolution as a result of isolation, mutation and selection
Why are isolation barriers important in speciation?
To prevent gene flow between sub-populations during speciation
What type of speciation does geographical barriers lead to?
Allopatric speciation
What type of speciation do behavioural or ecological barriers lead to?
Sympatric speciation
