1.7 Evolution Flashcards
What is evolution?
The changes in organisms over generations as a result of genomic variations.
What does L.U.C.A. stand for?
Last universal common ancestor.
How do genomic variations arise?
Mutations.
Why processes does evolution involve?
Selection, gene transfer and speciation.
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.
Changes in phenotype frequency are as a result of?
Stabilising, directional and disruptive selection.
What happens in stabilising selection?
An average phenotype is selected for and extremes of the phenotype range are selected against.
What happens in directional selection?
One extreme of the phenotype range is selected for.
What happens in disruptive selection?
Two or more phenotypes are selected for.
What are the two types of gene transfer?
Vertical and horizontal.
What is horizontal gene transfer?
Where genes are transferred between individuals in the same generation.
What is vertical gene transfer?
Where genes are transferred from parent to offspring as a result of sexual or asexual reproduction.
Why is natural selection more rapid in prokaryotes?
They can exchange genetic material horizontally.
Does vertical gene transfer happen quickly or slowly?
Slowly
What is speciation?
The generation of new biological species by evolution as a result of isolation, mutation and selection.
