A simple description of how natural selection and evolution works, in very simple, bullet point style steps, followed by an example.

1. Evolution by Natural Selection
By James Holmes

2. A random genetic variation
creates variation within a
population

3. This means that some members of
the species are better adapted to
their evironment than others

4. This increases their chance of
surviving long enough to
reproduce

5. When the organisms reproduce,
the beneficial trait is passed on to
the offspring

6. This process continues over many
generations, until the trait
becomes common place in the
population

7. An example
Random genetic mutation created variation in
the giraffe population, meaning some giraffes
had longer necks than others.

8. The giraffes with longer necks were
better adapted to their environment
as they could reach leaves that were
higher up, so they were more likely to
survive long enough to reproduce than
the giraffes with shorter necks.

9. When the giraffes reproduced they
passed their genetic information
onto their offspring, meaning the
offspring were likely to also have
long necks.

10. This process continued over many
generations, until long necks
became commonplace amongst
the giraffe population.

11. The End