Darwin suggested in his
book, ‘The Origin of
Species’ the following
ideas:
Modification with descent - the diversity of a species is a
result of evolution, i.e. species has modified gradually
from ancient ancestors unlike themselves
Natural Selection - a mechanism causing evolution –
individuals are best adapted to the environment will
leave the most offspring
He theorised…

All related organisms have a common
ancestor

Ancestral species adapted into new
habitats, modified according to their
niche, and became new species

Some species became extinct