Evolution:Natural Selection

Evolution• Change in inherited characteristics over time.

(Descent with modification)

Before the 1800’s few thought much about evolution 1. Most people thought the earth was only 6,000 years old (not 4.6

billion years old)

2. Few traveled to see similarities in species

3. Many people (of European descent) understood only the biblical story of creation.

http://mythicjourneys.org/bigmyth/

In the 1800’s scientists started to change people’s minds….

Lamarck• A French scientist who proposed that traits developed during a

parent’s life would be passed onto their kids.

Example: giraffes stretch their neck to reach tall leaves, this results in a long neck. This trait is then inherited by the kids.

Lamarck didn’t realize not all things are passed onto the offspring

=

Plastic Surgery does NOT get passed onto your offspring!

Before surgery After surgery

Genetics wasn’t described until the 1860’s by Mendel

Charles Darwin• A British scientist who studied nature and noticed similarities among

animals.

• He concluded that living things must be related and somehow they changed, or evolved, over time due to natural selection.

Natural Selection• An organism with the best traits for their environment is more likely

to survive and reproduce

Which mouse is better suited for

this environment?

Survival of the Fittest• Which moth has the

best traits for this environment? • What will happen to

the “unfit” moth?