The Origin of Life

• Life on Earth began about 3.5 billion years ago.

• The Earth was covered in a hot, thin soup of water and organic materials.

• Over time, the molecules became more complex

• This was explained by Miller and Urey’s Experiment in the 1950s

The Origin of Life: The Heterotroph Hypothesis

The Earth’s atmosphere was different.

Branching Tree Diagram for Evolution

FOSSILS

Fossils Form In Sedimentary Rock

-over time, pieces of earth erode and are worn away by wind and water. Layers of eroded earth are deposited on top of each layer. These layers press down until the bottom layers turn into rock.

Preservation in Volcanic Ash- Eruption of Vesuvius in 80 BC

Refrigeration of Soft Parts

This frozen baby wooly mammoth probably lived 22,000 years ago. It was found in Siberia in 1997.

Ice Man

(Austria)

Insects inAmber

Intermediate Forms

Vestigial Structures

appendix

vestigial leg bones

Comparison of Proteins: Hemoglobin Comparison

Species Amino Acid Differences

Gorilla 1

Rhesus monkey 8

Mouse 27

Chicken 45

Frog 67

Lamprey 125

Evidence from Early Stages of Development: Embryology

Lamarck: Theory of Use and Disuse

appendix

The selective use or disuse of organs leads to acquiring or losing certain traits during an organism’s lifetime.

These traits can then be passed onto offspring. Over time, there is a change in the species.This theory is not true!

Darwin

Voyage of the Beagle1859- On the Origin of Species by Means of Natural Selection is written.

Galapagos Tortoises

Marine Iguana

FlightlessCormorant

Darwin found different

characteristics on different islands- each well suited to their environment.

Theory of Natural Selection

•Species are not perfect or unchanging.•There are different traits among offspring called variation. This variation is inherited.•There is competition for resources-•a struggle for existence. • This leads to survival of the fittest.

Sources of Variations

•mutations

Changes in Species Resulting From:

•resistance (insects, bacteria)•industrial melanism (peppered moths)

Industrial Melanism- Kettlewell’s moths

European peppered moths have 2 color variations. The darker moths (with more melanin) were rare until industrial pollution in the 1850s, when tree trunks darkened due to soot.

Species – a group of organisms that can breed together under natural conditions to produce fertile offspring.

X

Father = tigerMother = lion

Father =lionMother =tiger

Tiglon Liger

sterile and do not mate under natural conditions- not a species

Gradualism versus Punctualism in Evolution

Most of the time evolution occurs over many, many years. This is called Gradualism.

Sometimes it occurs very quickly over several generations. This is called Punctualism.

When the peppered moths changed cover over several generations, this was an example of ???