1. Evolution Evolution is the process by which Populations
accumulate inherited
changes over time.

2. Includes three major ideas:
Theory of Evolution
Includes three major ideas:
All organisms developed from a single
life form that lived on Earth billions of
years ago.
All organisms share common
ancestors.
All species arise from other species.

3. Common Ancestor Scientist have found evidence that all
organisms on earth share a common
ancestor…all organisms are related.
Similar bone structure in the upper arm suggests these animals have a common ancestor.

4. Two processes are necessary for populations to change over time.
Mutations
Natural Selection

5. Mercury-Poisoning Mutation
Mutations are sudden changes in the
DNA of a gene. These changes can
be passed on from parent to
offspring.
Some mutations are helpful.
Some mutations are harmful.
Some are neither helpful or harmful.
Helpful: such as a mutation that causes bright color patterns in flower petals…all the better to attract pollinating insects.
Harmful: Albinism is an inherited mutation. Albinos lack protective skin pigments therefore are prone to skin cancer and do not see well in bright light.
Mercury-Poisoning Mutation

6. Finches from the Galápagos Islands
Charles Darwin
In 1831 Charles Darwin (22 years old) voyaged on the HMS Beagle
to the Galapagos Islands where he made many observations
about the different species of plants and animals.
He was most interested in the birds that lived
in the different Islands. In 1859 he wrote a book
called “On the Origin of Species”. In it Darwin
presented his theory of evolution by natural selection.
H.M.S. Beagle
Five year voyage of H.M.S. Beagle ( )
Finches from the Galápagos Islands

7. Natural Selection Natural selection is a process in which organisms
that are better able to survive and reproduce in
an environment are more likely to pass their
traits on to future generations.
“Survival of the Fittest”
Traits are selected
Traits must be passed from one generation to the next
Changes occur in response to the environment

8. Adaptation An adaptation is a characteristic
or trait that helps an organism
survive in its environment.
Adaptation plays a major role in
natural selection.
An adaptation makes an organism
more suited to its environment,
and therefore more likely to
survive and pass on its traits to
the next generation.

9. Adaptations
Some adaptations are body parts. Other adaptations are behaviors.
A tiger’s teeth are adapted for
tearing and chewing. A tiger’s fur
helps it blend into tall grasses.
Feathers are adaptations used for
flight. A bird’s beak is adapted to
the food it eats. What type of
food do you think this bird eats?

10. Adaptations Cont. Leaves of green plants are adapted
to absorb sunlight. Flowers are
adaptations that attract insects that
can help a plant reproduce. How do
you think a plant’s stem helps it survive?
A cactus is adapted to life in a
desert. Its thick stems store
water. A waxy coating on the plant
reduces water loss.

11. Adaptations Cont. A sea turtle retreats into its shell
when it senses danger. What are
some other adaptations of sea turtles?
A dandelion’s seeds are easily dispersed
by the wind. How do you think this
adaptation help the plant’s species?
How do you think this
insect adapted to living
in or near trees?

12. Peppered Moths The European peppered moth
often rests on the trunk of trees
and is found in two colors: one
light and one dark.
Before 1850, most peppered
moths were light. After 1850,
industry created pollution that
blackened the tree trunks. Light
moths became rare, while the
once-rare dark peppered moths
became more common.

13. Adaptations of Peppered Moths
Which moths are better adapted to the tree that they are on?

14. Unpolluted Birch Forest
The light variety of the peppered moth on a birch tree trunk.
The dark variety of the peppered moth on a birch tree trunk.

15. Polluted Birch Forest
The light variety of the peppered moth on a soot-blackened tree trunk.
The dark variety of the peppered moth on a soot-blackened tree trunk.

16. Evolution Mini Assessment Review
__________ is the process by which populations accumulate
inherited __________ over __________.
Evolution
changes
time
Three Major Ideas of the Theory of Evolution:
Organisms developed from a single life form that lived on Earth billions of years ago.
Organisms share common ancestors.
Species arise from other species.

17. Evolution Mini Assessment Review
Two processes are necessary for populations to change over time:
1. __________ 2. ___________
Mutations
Natural Selection
__________ are sudden changes in the ______________ of a
gene. These changes can be passed on from parent to offspring.
DNA

18. Evolution Mini Assessment Review
__________ in 1859 wrote a book called “On the Origin of
Species”, it was about __________ by __________ selection.
Charles Darwin
evolution
natural
__________ is a process in which organisms that are better
able to survive and reproduce in an __________ are more likely
to pass __________ traits on to future generations.
Natural selection
environment
favorable (good traits)

19. Evolution Mini Assessment Review
An __________ is a characteristic or trait that helps an
organism survive in its environment.
Adaptation
A species can become __________ if its environment changes
to quickly.
extinct