10.1 Early Ideas About Evolution

What is evolution?• Evolution is the process

of biological change by which descendants come to differ from their ancestors.

• Evolution is a central theme in all fields of biology today.

Charles Darwin• Natural selection was the

theory he proposed to explain evolution.– He attempted to provide

reasons for the biological diversity on Earth.

• However, Darwin was not the first scientist to study evolution.

4 Scientists before Darwin…

•Carolus Linnaeus•Georges Buffon•Erasmus Darwin

• Jean-Baptiste Lamarck

Carolus Linnaeus• In the 1700s, he

developed a classification system to help organize all types of organisms into categories based on their similarities.– Scientists still use his

classification system today.

Georges Buffon• He proposed that

species shared ancestors rather than arising separately.– Species is a group of

organisms so similar to one another that they can reproduce and have fertile offspring.

Erasmus Darwin• Charles Darwin’s

grandfather• Proposed that all

living things were descended from a common ancestor and that more-complex forms developed from less-complex forms

Jean-Baptiste Lamarck• He believed that

species evolved into different forms rather than becoming extinct…flawed idea!

Jean-Baptiste Lamarck• He proposed the idea of inheritance of

acquired characteristics:– changes in an environment caused an organism’s

behavior to change– this would lead to greater use or disuse of a

structure or organ. – the structure would become larger or smaller and

would then be passed down to offspring• For example: giraffes’ long necks

So….Darwin based his studies on the work of these four men and developed his theory

known as evolution by natural selection.