Animals develop physical features over many generations through natural selection that help them obtain food, stay safe from predators, build homes, withstand weather, and attract mates. These features are not acquired during an animal's lifetime but are inherited from parents and include traits like beak shape, number of fingers, fur color and thickness, and nose or ear shape. Many organisms avoid predators through camouflage, hiding, fleeing, or warning signals. The peppered moth example illustrates how a dark color mutation provided camouflage for moths in polluted areas, making the dark form more common than the light form.

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.