EvolutionEvolution

Evolution, n. [L. evolutio - an unrolling]

1: a process of change in a certain direction

2: a theory that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations

Charles Darwin

• naturalist and collector

• amateur geologist

• avid reader

• and soon to be traveler

Darwin’s ThoughtsDarwin’s Thoughts

Why are some animals only in certain places?

How old is the earth?

Where do

fossils fit in?

Has everything always been

here on Earth?

Where did humans

come from?

Why are there so

many different kinds of animals?

Do plants ever

change?

Darwin’s Voyage 1831- 1836

Darwin’s Voyage 1831- 1836

Darwin’s ObservationsDarwin’s Observations

• Buried fossil skeletons of animals no longer around

• Finches with small changes in beak shape associated with different diets

• Tortoises in different ecosystems with different shell types

• Layers of sedimentary rock exposed from an earlier time

Evidence for EvolutionEvidence for EvolutionGeologic Time Scale

• Fossil Record

• Homologous Structures

• Embryology

• Molecular Biology

Is the Earth Old Enough?Is the Earth Old Enough?

Tim

e S

cale

for

Lif

eTim

e S

cale

for

Lif

e

Earth’s Cool

Dance – the

Continental Drift

Earth’s Cool

Dance – the

Continental Drift

Permian – 225 mya Triassic – 200 mya

Jurassic – 135 mya Cretanceous – 65mya

Present

Best Geology on Earth – New England

Best Geology on Earth – New England

Trilobites at Lake Champlain

430 mya(Ordovician)

Dinosaurs in Hartford

200 mya(Triassic)

Evidence for EvolutionEvidence for Evolution• Geologic Time Scale

Fossil Record

• Homologous Structures

• Embryology

• Molecular Biology

The Fossil RecordThe Fossil Record

BarbellusBarbellus

A Whale of a StoryA Whale of a Story

Evidence for EvolutionEvidence for Evolution• Geologic Time Scale

• Fossil Record

Homologous Structures

• Embryology

• Molecular Biology

Homologous StructuresHomologous Structures

Evidence for EvolutionEvidence for Evolution• Geologic Time Scale

• Fossil Record

• Homologous Structures

Embryology

• Molecular Biology

Evolution Replays in the Embryo

Evolution Replays in the Embryo

Whale EmbryosWhale Embryos

Evidence for EvolutionEvidence for Evolution• Geologic Time Scale

• Fossil Record

• Homologous Structures

• Embryology

Molecular Biology

Molecular Biology CluesMolecular Biology Clues

• Proteins– Enzymes – amino acid

sequences

• Genetic Material– DNA base sequences

• Nuclear DNA• Mitochondrial DNA

Clues from Cytochrome CClues from Cytochrome C66*

36

31

20

17

13

Human Pig Duck Snake Tuna Moth Yeast

* Number of base differences in gene coding for Cytochrome C

Darwin’s Dangerous IdeaDarwin’s Dangerous IdeaWe thus learn that man is descended from a hairy,tailed quadruped, probably arboreal in its habits,and an inhabitant of the Old World. This creature,If its whole structure had been examined by a naturalist, would have been classed amongst the Quadrumana, as surely as the still more ancientprogenitor of the Old and New World monkeys.

“The Descent of Man”