Download Natural Selection Notes

Natural Selection vs Selective
Breeding
Natural Selection
Natural Selection

Think!
Does every organism get a chance to
pass on it’s genes?
 Why / why not?
 What could this have to do with
evolution?

Natural Selection Notes
Natural selection is the process by which
organisms that are better suited to their
environment survive and reproduce,
while those less well suited fail to do so.
 So the better adapted organisms are
more likely to pass their genetic
characteristics to the next generations.

The Peppered Moth
Moths with light wings were
camouflaged on trees
Moths with dark wings were easy
to spot by predators
What would you expect to happen
to the ratio of each type?
Along came the industrial
revolution – and lots of pollution
Tree trunks were discoloured by
pollution
Now the black moths had the
advantage
What would you expect to happen
to the ratio of each type?
As coal burning stopped, the trees
returned to their natural color
The Peppered Moth

Watch this video
Natural Selection Summary
Sexually reproducing organisms show
genetic variety
 Some organisms are better adapted to
their surroundings than others
 This allows them to survive and pass on
these favorable genes – natural
selection
 Over time, natural selection can result in
a change in a population – evolution!

Selective Breeding
Selective Breeding

People rely on plants and animals to
supply us with many of the things we
need.

Can you think of some examples?
Selective Breeding

All of the species of plants and animals
that we eat, use, and breed today are
derived from wild ancestors.

However, some look very different. Have
a look at the cows on the next slide…
Selective Breeding
‘Wild’ cow
‘Beef’ cow
What differences can you see?
Selective Breeding

Selective breeding is the selection of
individuals which possess desirable
characteristics and breeding them to
produce the next generation.