Early Ideas about Evolutionand Darwin’s ObservationsSECTIONS 10.1 & 10.2

A few things first…

What is evolution?

Who was the first person to have thoughts about evolution?

Is it still going on today?

Evolution

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

What does that even mean???

Before Charles Darwin…

Carolus Linnaeus: 1700’s SwedenBotanist who organized organisms based on

their similarities. Did not believe organisms were fixed and did not

change

Why would organizing things according to similarities make one think of evolution?

What does it mean when something is “fixed”?

Georges Louis Leclerc de Buffon

1700’s France (obviously) Also rejected the idea of fixation

First to propose organisms come from common ancestors Dismissed the idea the earth was only 6000 years old.

Went off of geology instead

Why would coming from a common ancestor support evolution?

How did geology not support the theory of the earth being 6000 years old back then?

Erasmus Darwin

1731 England, Charles Darwin’s grandpaActually a doctor and a poetAlso put forth the idea of common ancestors

Suggested common ancestors were less complex

Why would he suggest common ancestors were less complex?

Jean-Baptiste Lamark

1809 France Naturalist who proposed all organisms evolved towards

perfection Did not think organisms became extinct Thought changes in the environment would lead to the

use or disuse of structures/organs

Why would he think organisms did not become extinct How could environment lead to use/disuse of organs or

structures? Examples?

Geology!

What exactly is geology?

Different theories about geologic change helped to prepare Darwin’s theory of evolution.

Catostrophism Proposed by Georges Cuvier

Examples?

Quickly change the layout of landforms or other livable areas fairly quickly

Can also cause mass extictions

https://www.youtube.com/watch?v=BUREX8aFbMs

GradualismProposed by James Hutton

Some changes in landforms were caused by forces over a long period of time

What “forces” could be powerful enough to carve through rock over long periods of time?

https://www.youtube.com/watch?v=ktf73HNZZGY

What are some examples of landforms that were subject to gradualism?

Is this still going on today?

Uniformitarianism

Developed by Charles Lyell

Changes or processes that shape earth are uniform through time

What does it mean if something is uniform?

How are we able to tell uniformitarianism has occurred in rock formations?

Charles Darwin

Left on a voyage in 1831 on the HMS BeagleJust keeping the captain company

Meant to map the coast of South America and nearby islands

Where did he do most of his observations?

Observation of differences

Variation: the difference in physical traits of an individual from those of other individuals in the group it belongs in

Variation in Finches

What is an adaptation?

What allows these adaptations to occur?

Can these adaptations get passed on to offspring?

What happens if adaptations get passed on in a population for a long time?

Fossil Evidence also supports Darwin’s theory

He found a giant armadillo skeleton in ArgentinaGlyptodon

Geologic Evidence

Found fossils of sea life in the Andes Mountains

How could that possibly happen?

Used all he found as material in his book On the Origin of Species