Precambrian Time

•

•

•

The Earth Forms6 BYA The

Solar system formed from

swirling gases and dust

4.5BYA Rocks in the solar system condensed to form Earth

The center of Earth was melted by great pressure and intense heat.

4.1BYA The surface of Earth cooled forming the crust

An atmosphere formed as Earth cooled.

Oldest rock found in Western Australia

primitive atmosphere forms from volcanic eruptions

Did NOT contain oxygen gas

Oceans form from water vapor released in eruptions &

maybe comets

4.6 BYA Precambrian Time

○

○

○

4.0-3.8 BYA Precambrian Time

A molten Earth forms

Comparison of Atmospheres

Miller & Urey Experiment (1953)

◎

◎

How did the 1st cells form?

◎

◎

◎

◎

3.5 BYA Precambrian Time

○

○

○

3.0 BYA Precambrian Time

○

○

○

○

2.1 BYA Precambrian Time

◎○

○

○

Evolution of Eukaryotic Cells

◎

Endosymbiotic Theory◎

◎

◎

630 MYA Precambrian Time

◎

Species include:

jelly fish; coral

stalks; segmented

worms; algae

From Cells to

Humans…

the evolution of life

Paleozoic Era540,000,000 yrs ago to 250,000,000 yrs ago

Life starts in the seas and moves onto land

Paleozoic Era

Ordovician Period (490-445 MYA)

1st vertebrates (in ocean) - jawless fish

(filter feeders)

The lamprey of today is a parasite. The hagfish is a scavenger.

Creatures of the

Ordovician Period

Paleozoic Era

Silurian Period (445-415 MYA)

◎Ozone layer (O3) formed which blocks harmful UV rays. Life

could evolve on land

◎1st land plants (mosses & ferns) followed by 1st land animals

(invertebrates like spiders & scorpions).

◎1st jawed fish (later evolved into sharks-made

of cartilage).

Paleozoic Era

Devonian Period (415-360 MYA)

◎1st vertebrates on land – amphibians

○ Evolved from the lobed-fin fish which include the lungfish.

Paleozoic Era

Devonian Period (415-360 MYA)

◎ “Age of the Fish” (giant armored fish).

◎1st bony fish (scales and swim bladder for buoyancy).

View of Earth—Devonian Period

Life of the Devonian

Period

Paleozoic Era

Carboniferous Period (360-300 MYA)

◎◎Amphibians & insects dominate and become large

○ (dragon flies-1m wing span; cockroaches-10 cm long).

View of Earth—Carboniferous Pd

Mesozoic Era

Triassic Period (250-200 MYA)

Pangaea (supercontinent) formed

Triassic Period (250-200 MYA)

First Dinosaurs

(small in size)

Pisanosaurus

Length:3 feet Height:1 foot Weight:15 pounds

Eoraptor:

Length:3 feetHeight: 1 footWeight:20 pounds

Mesozoic Era

(Age of the Reptiles)

Mesozoic Era

Jurassic Period (200-145 MYA)

Pangaea starts to separate

Mesozoic Era

Jurassic Period (200-145 MYA)

1st mammals (small rodents).

Mesozoic Era

Jurassic Period (200-145 MYA)

1st birds (Archaeopteryx).

• Jaws and bone structure like dinosaurs

• Bones are hollow, like birds• Had feathers

Continents in modern positions

Mesozoic Era

Cretaceous Period (145-65 MYA)

Mesozoic Era

Cretaceous Period (145-65 MYA)

Flower plants (angiosperms) evolve & dominate

Tertiary Period (65 MYA to 2.6 MYA)

◎Mammals dominate: increasing in size

◎Earliest prehistoric humans (approx. 4 MYA).

◎Flowering plants (angiosperms) dominate

◎Grasses develop, grazing animals become even larger

Cenozoic Era

(Age of the Mammals)

Cenozoic Era

Quaternary Period (2.6 MYA to Present)

◎Modern humans evolve