Charles Darwin was a famous scientist in
the 1800s.
He was famous because he came up with an idea
that changed the way we think about life on earth forever; 
the theory of evolution. 
Darwin loved animals and studied them all of his life.
In 1831, he went on an exciting voyage aboard the
ship, HMS Beagle.
The Beagle visited the coast and islands
of South America and Australia,
where Darwin observed and collected a
wide range of weird and wonderful plants and animals.
When he got back to England,
he analysed his collection closely. 
That was when his ideas about evolution started to form.
Darwin had found around 15 different species of finch when he was on the Galapagos Islands.
He noticed that the birds were similar to other finches in lots of ways, 
but their beaks were all different shapes.
Darwin looked into it further.
He realised that the different beaks matched
the type of food available on each island. 
The frinches who ate insects had skinny,
pointed beaks, so they could pick them up
better, and those that ate
hard fruits had beaks that were sharp, so they
could get through the skin.
Darwin decided that there was only one way
this could have happened.
The birds must have adapted to their
environment over time. 
This lead him to another idea,
which he called the survival of the fittest.
In any environment, plants and animals
from the same species
show natural variation in their physical
characteristics,
such as neck length in giraffes.
Darwin suggested
that those plants and animals
best-suited to their environment are more
likely to survive and pass on their
characteristics to their offspring.
Over a long period of time, the
characteristics of the surviving members of the species
will come to predominate.
Confused?
Take the peppered moth.
In London in the early 1800s,
98% of peppered moths
had light coloured bodies. Only 2%
were dark.
The light moths with very happy, because they were
the same color as the trees,
which meant they could easily hide
from hungry birds.
The dark peppered moths were easy to see and...
well...eat.
Then came the factories and the smoke of the
industrial revolution.
Many trees turned black with soot and
suddenly,
it was the dark moths who were able to
survive better in their environment.
By 1895, the dark peppered moth
made up 95% of the
population. That's quite a turnaround!
The process of natural selection usually
takes much longer,
but this is a good example of how it
works.
What about us humans?
Good question.
Darwin went on to suggest that humans
share a common ancestor with modern apes.
This was controversial,
because it went against the religious
beliefs of many people.
Darwin's theory of evolution by natural
selection had a great impact on the world.
Today it is widely accepted as our best scientific explanation
of how life on earth works.
