Evolution

Change over time; the process by which modern organisms have descended from ancient organisms

EvolutionOnly a theory?

Some basic definitions• Theory: a well-

substantiated and accepted explanation that incorporates facts, laws, inferences, and tested hypotheses.

In science, you don’t get any better than a theory.

Spontaneous Generation- life produced from non-life

Biogenesis-life arises only from life

According to Jean van Helmont from the 3rd century B.C., when grains of wheat are place in a container and left for 21 days, mice will form from the fermenting wheat.

False

Animal Locomotion• What different ways do these animals

move?• What traits does each animal have that

help it move as it does?

Darwin’s Voyage

Charles Darwin – “The Father of the Theory of Evolution”

H.M.S. Beagle• Sailed around the world in

1831• Darwin began to make

observations about the species in the world

Darwin’s Observations• An enormous number of

species inhabit the earth• Organisms are well suited to

their environment• Organisms have many ways

to survive and produce offspring

Where Organisms Live• Certain organisms live in some areas

but not others– Rabbits and Kangaroos live in the same

type of environment– Australia has Naturally Kangaroos but

not Rabbits– England has Rabbits but not Kangaroos

Fossils• Some fossils look like

organisms that are alive today

• Other fossils look unlike any creature Darwin had ever seen

• Why do species disappear?• How are organisms in

fossils related to living species?

Galapagos Island• Islands are close

together with very different climates

• Darwin saw finches with different shaped beaks on different islands

• Could similar organisms on different islands once have been members of the same species?

Fruit

CactusSeeds

Insects

Giant Tortoise