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Origin of the Solar System -

Formed 4.5 billion years ago

Used a dense cloud of interstellar gas and dust

Collapsed due to a shock-wave of a nearby star

When dust cloud collapsed it formed solar nebula and a spinning disk

The gravity in the center caused so much pressure it formed the Sun

Farther out of the disk it was clumping up and formed the planets due to the clumps having lots of mass and gravity.

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First Plants -

Lived during the Middle Ordovician around 470 million years ago

Liverworts and mosses were the first plants

Able to reproduce with spores

First Fungi -

First appeared one billion years ago

Extremely ancient group

Oldest is known as Prototaxites which was common around Devonian Period

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The origin of atmospheric oxygen -

4.6~3.5 Billion Years Ago (BYA)- No Atmosphere:

surface was molten

gas from volcanos help Earth cool

after half a billion years Earth was cool enough for water to form hydroshpere

3.5~2.4 BYA - Cyanobacteria Produce Oxygen:

No free oxygen

Oxygen first produced by photosynthetic prokaryotic organisms

Cynobacteria trapped and bounded sediments, forming wavy structures (stromatolites)

2.4 BYA~600 MYA - Iron Soaks Up Oxygen

Iron dissolved into oceans

Settled to ocean floor

Iron oxide stopped being deposited and oxygen was able to start building up

600~550 MYA - Oxygen Levels Boom:

Rapid build up of free oxygen

Little direct effect on life

550~300 MYA - Life Booms with Increased Oxygen:

Oxygen gave life new possiblities to explore

Atmospheric oxygen level 2% volume nessecary to make compounds

Oxygen levels fluctuated between 15-30%

300 MYA to NOW - Oxygen Drops from 35% to 21%

Oxygen levels reached max of 35%

May have contributed to large insect size

Rainforsts and climate evolved

Dropped to a stable 21%

Recent levels:

Co2 about 280 ppm

Co2 levels rise due to fossil fuel increase

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Trilobites -

An extinct marine arthropods.

Earliest known arthropods.

Highly diverse and extensive fossil record.

Went extinct during the Permian mass extinction.

Dinosaurs -

Diverse group of reptiles

Closest ancestor to modern day birds

Went extinct during the end of the Cretaceous Period

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Ice Age

During these periods land in North America and Northern Europe were covered by giant ice fields and glaciers.

There are periods within ice ages that scientists define as

Glacial – A glacial period is a cold period when the glaciers are expanding.

Interglacial - An interglacial period is a warm period where the glaciers may be receding.

The Five Major Ice Ages -

1. Huronian

2. Cryogenian

3. Andean - Saharan

4. Karoo

5. Quateranry

The last ice age was called “The Great Ice Age”, and it occurred 11,000 years ago.

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Humans -

Originated from ape like ancestors

First humans migrated out of Africa to Asia

Evolved over a period of 6 million years

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First Amphibians -

Found around 370 million years ago

Developed around the Devon Period

Similar to the modern coelacanth and lungfish

Used to walk along the sea floor but it's legs helped it go to land and develop lungs

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First Birds -

Known as Archaeopteryx 150 million years ago

Birds had evolved before then

A group of primitive birds evolved into the modern day birds during the late Cretaceous

Overlap period where dinosaurs, primitive birds, and modern birds co-existed

First Mammals -

Known as Morganucodontids 210 million years ago

Tiny shrews

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First Flowering Plants -

Known as Archaefructus 130 million years ago

Probably lived in or grew near water

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5 Mass Extinctions -

Ordovician-silurian Extinction: 440 million years ago. Small marine organisms died out.

Devonian Extinction: 365 million years ago

Permian-triassic Extinction: 250 million years ago

Triassic-jurassic Extinction: 210 million years ago

Cretaceous-tertiary Extinction: 65 million Years ago