Unit 1 Topic 7- Évolution Flashcards
What is evolution?
The changes in organisms over generations as a result of genomic variations
What is natural selection?
The non-random increase in frequency of DNA sequences that increase the rate of survival
What is speciation?
The creation of a new biological species caused by evolution as a result of isolation, mutation and selection
Who founded the theory of evolution?
Charles Darwin
What is stabilising selection?
A form of natural selection that favours middle characteristics in a range of variation, extremes survive less well
What is directional selection?
One extreme of the phenotype is selected because it survives better. This is commonly seen during periods of change.
What is disruptive selection?
Extremes of phenotypes are favoured and middle characteristics survive less well
What are the 2 types of gene transfer?
Vertical and horizontal gene transfer
What is vertical gene transfer?
When genes are transferred vertically from parent to offspring. This can be a result of either sexual or asexual reproduction and it occurs in both eukaryotes and prokaryotes
What is horizontal gene transfer?
Genes are transferred horizontally between individuals in ytr same generation. This occurs only in prokaryotes and results in faster evolutionary change
Define a population
A group of organisms of one kind
Define a species
A group of organisms that can interbreed to produce fertile offspring
Define selection pressures
Pressures from the environment that act on individuals (something that makes it difficult to survive)
Define selective advantage
The ability of an organism to cope and survive selection pressures
Define speciation
The formation of a new biological species by evolution as a result of isolation, mutation and selection
