- variation is the difference between individuals of the same species.
- when two different species breed, they produce infertile young known as a hybrid.
- continuous variation doesnt fit in groups easily and values have a range e.g. height, weight
- discontinuous variation fits into a small number of clearly defined groups e.g eye colour
- speciation- process of evolution when new species form
- variation is due to; genetic causes (inherritance) or environmental causes
- evolution: 1)variation- population varies slightly. 2) over production-produce more young to survive to adulthood. 3) struggle for existance- competition between organisms. 4)survival-those with advantageous characteristics are more likely to survive. 5) better adapted organisms more likely to reproduce/pass on good genes. 6) gradual change-more in population will posses good characteristic and others will be lost,