Theories in Evolution

Jean Baptiste Lamarck (1809)

• published a theory of evolution

• observed ‘line of descent’ with fossils

Jean Baptiste Lamarck (1809)

• proposed microscopic organisms arose spontaneously from non-living sources

Jean Baptiste Lamarck (1809)

• new species evolved from simple ones

---> “use and disuse” resulted in formation of body parts [giraffes reach for leaves resulted in long necks]

• Inheritance of Acquired Characteristics

characteristics acquired in a lifetime passed to offspring (short hair, long necks, etc...)

Charles Darwin

• group of 20 small islands approx 1000 km off the coast of Ecuador

• few animal species• species resembled

some animals off the west coast of SA (nearest land mass)

• single act of creation did not seem to support the trends Darwin observed

• realized species had become modified from original

Summary of Darwin’s Theory

1. Organisms differ; variation is inherited 2. Organisms produce more offspring than

survive 3. Organisms compete for resources 4. Organisms with advantages survive to

pass those advantages to their children 5. Species alive today are descended with

modifications from common ancestor

Color of fur Black Tan Tan and Black

Cream

Age at death 2 months 8 months 4 months 2 months # pups produced by each female

0 11 3 0

Running speed 8 cm/sec. 6 cm/sec. 7 cm/sec. 5 cm/sec.

Who is winning? Explain.

Name George Dwayne Spot Tyrone Age at death 13 years 16 years 12 years 10 years # cubs fathered 19 25 20 20 # cubs surviving to adulthood 15 14 14 19 Size 10 feet 8.5 feet 9 feet 9 feet

Who is winning? Explain.

• How would Darwin explain the Giraffe?

• How would Darwin explain the hover flies?