• The sun formed 4.6 billion years ago from a dust and gas cloud left behind by supernovae.

• Alongside the sun an accretion disk formed from leftover material

4.5-4.4 billion years ago

• From the accretion disk, all 8 planets including Earth formed

• Earth formed from heaver elements left in the inner solar system after lighter elements were carried out to the outer solar system

• Characterized by Earth's hellish conditions

• Impact with a proto-planet formed the moon

• Atmosphere was very different compared to today, mostly consisting of methane and lacking oxygen

• Fossil records of the Precambrian are buried under many layers of rocks or destroyed

Archean Era: 4 - 2.5 billion years ago

• Early oceans formed, along with small proto-continents

• The oldest remaining rocks are dated to this era.

• Cyanobacteria, some of Earth's first organisms, appeared 2.5 billion years ago

• Cyanobacteria over time helped oxygenate the atmosphere as they took in CO2 and pumped oxygen out into the atmosphere

• Oxygen was first produced by cyanobacteria

• Oxygen was absorbed by iron in the oceans, which released the oxygen once they dissolved and oxidized.

• Around the same time oxygen appeared in the atmosphere, Earth's first glaciation started

• Most of Earth's surface was covered in ice sheets

• Stable continents began to form and break apart over time

• Complex life also formed during this time

• The first multicellular organisms evolved around 1.2 billion years ago, according to fossil records

• The first multicelllular organisms were algae

• The first fungi appeared around a billion years ago

• Fungal structures were some of the oldest plant fossils discovered

• Formed through chemical reactions between oxygen and uv radiation from the Sun

• Started forming 2 billion years ago, and completed formation 600 million years ago

• The oldest fossil records of invertebrates date back around 660 million years

• They were some of the first multicellular organisms

• 542-485 million years ago

Paleozoic Era:

• 541-252 million years ago

Phanerozoic Eon

• 538 million years ago - now

• insects first evolved 480 million years ago

• Insects evolved from crustaceans

• Vertebrates first evolved 500 million years ago.

• The earliest nown vertebrates were jawless fish.

• At least once in its life, Earth was completely covered in ice sheets

• This is known as Snowball Earth

• Plants first appeared 435 million years ago

• They were some nof the first organisms to live on land,

• Land animals came shortly after plants on land.

• Many animals loved on land because of competition for resources in the ocean

• Amphibians evolved from a lungfish ancestor 370 million years ago

• Amphibians dominated the land for a period of time until reptiles came along

• Caused by rises in sea level

• Wiped out up to 80% of Earth's species

• Evolved from amphibians

• Later came to replace amphibians as the dominant land vertebrates

• Caused by global warming

• Wiped out 95% of Earth's species

• Dinosaurs are classified as reptiles

• However, they had many distinctions from other reptiles, such as their size and legs being under their bodies

• Mammals evolved from a sector of reptiles called therapsids

• Mammals are some of the only warm blooded organisms

• Birds evolved from a group of dinosaurs called theropods.

• Birds are some of the only other warm blooded animals aside from mammals

• Flowering plants spread fast due to their high reproduction rates and short reproduction cycles

• The last major mass extinction on record

• Caused by the fallout of an asteroid impact in modern day Mexico

• Wiped out 75% of Earth's species

• Last of 5 major ice ages

• Ongoing

• The first human species, Homo habilis, evolved 2 million years ago in Africa

• Modern humans, called Homo sapiens, evolved around 200,000 years ago

• Eliminated about 85% of Earth's species

• 251-201 million years ago

Mezozoic Era

• 251-66 million years ago

• Caused by mass volcanic eruptions

• Wiped out ~75% of Earth's species

• 65-23 million years ago

Cenozoic Era

• 65 million years ago - now