1.  Animals depend on physical
features to:
 obtain food
 keep safe
 build homes
 withstand weather
 attract mates.

2.  Do not develop during an animal's life but over
many generations.
 Examples:
 shape of a bird's beak
 number of fingers
 color of the fur
 thickness or thinness of fur
 shape of the nose or ears

3.  Defensive adaptations include:
 Predator avoidance
 Hiding and camouflage
 Group defense
 Fleeing
 Signal
 Warnings

4.  Many organisms avoid predators by the use of
cryptic coloration.
 A requirement of camouflage in many cases is
that the individual choose an appropriate
background.

5. Natural selection rests on three facts:
1. Organisms produce more offspring than can survive.
2. Individuals vary in their characteristics.
3. Many characteristics are inherited by offspring from
their parents.

6. • Some individuals will be better suited to their
environment
 They will survive and reproduce
more successfully than individuals
without those characteristics.
• Future generations: contain more genes from
better-suited individuals.
• Result: characteristics will evolve over time to
resemble those of the better-suited ancestors.

7.  Two Kinds:
 White speckled moth
 Black moth.
 In early 1800’s dark form was very rare.
 Dark form caused by dominant mutation that
occurs spontaneously.

8. Peppered moths rest on trees and depend
on camouflage for protection.

9.  Unpolluted Areas: trees are covered
in lichens and the light form of the
moth is hard to see.
 In mid 1800’s air pollution in British
cities covered trees with soot.
 In cities dark form became common
and light form rare.

11.  Inmid 1950’s pollution
controls were introduced in
Britain and frequency of the
black moth form has declined
since then.