U3 Evolution Flashcards
What is the only source of new alleles?
Mutation
What is a mutation?
A random change to genetic material
What can increase the rate of mutation?
Radiation and other chemicals
What does variation allow for?
A population to evolve and adapt to a changing environment
When does natural selection occur?
When species produce more offspring than the environment can sustain and selection pressures occur.
Who survives natural selection?
The best adapted survive allowing them to reproduce and pass on favourable alleles
When does speciation occur?
When a population is split by an isolation barrier
What is speciation?
Formation of a new species via mutation which was passed on as a result of natural selection
What are the events in speciation?
Population separated by an isolation barrier
Different mutations occur based upon different selection pressures s
Different species are formed as a result of natural selection and favourable alleles being passed on
What are the three types of isolation barrier?
Ecological, geographical and behavioural
What is an example of an ecological barrier?
Different pH levels or habitats
What is an example of a behavioural barrier?
Different mating times or areas
What is an example of a geographical barrier?
A mountain or lake
