Evolution of Species Flashcards
What is genetic variation caused by?
Slightly different versions of the same genes between members of the same species
How does variation occur?
Mutations
What are mutations?
Spontaneous, random changes to the genetic material of an organism
What is the only way that alleles can be added into a population?
Through mutations
What is an allele?
A form of a gene
What environmental factors can increase the rate of mutations?
Radiation (Gamma Rays, UV Rays) and Chemicals (Nicotine, Bromine)
What is adaptation?
An inherited characteristic that makes an organism well suited to surviving in its environment/niche
Why are adaptations needed?
To help organisms survive changing environments
What is natural selection?
When organisms of a species produce more offspring than are going to survive because there are not enough resources for them
When do selection pressures occur?
When there aren’t enough resources to allow all members of a species to survive
What is speciation?
When two or more species are formed from one original species
What are the four stages of speciation (in order)?
1) Isolation
2) Mutation
3) Natural Selection
4) New Species
What is isolation?
When one population of a species is separated by an isolation barrier
What can the isolation barriers be?
Geographical (mountains, rivers)
Ecological (pH, salinity)
Behavioral (different breeding seasons)
What is a species?
An organism that can reproduce to produce fertile offspring
