EARTH’S HISTORY

Earth Forms 4.6 billion years ago Started out as a hot ball of lava As it cooled the crust formed

Oldest piece of rock ever found 4.4 billion years old Found in Australia Zircon crystals

First evidence of life 3.5 billion years ago Prokaryotes: Archaea and bacteria

First fossils of Algae and Bacteria Cyanobacteria or “blue green algae” May have formed stromatolites

Free Oxygen in the atmosphere Cyanobacteria went through a process called photosynthesis. This is where carbon dioxide is converted into oxygen 21 percent of our atmosphere is made of oxygen

First fossil of complex organism Eukaryotic cells 1.8 billion years ago

First abundant life found on fossil record 540 million years ago Cambrian Explosion Major diversification in life forms appeared

First Fish Jawless fish 520 million years ago

First Land Plants 482 million years ago Very simple plants that lacked stems and roots such as liverworts

First Land Animals Tetrapods- animals from the sea use their front legs as crutches to pull themselves around. 360 million years ago

Largest Mass Extinction 250 million years ago 90 percent of all species perished May have been due to the volcanism of the Siberian Traps

First Dinosaurs 230 million years ago They started out small and then grew in size

Pangea splits 175 million years ago The plates began to pull apart This has been a cycle over the last billion years

First Mammals 160 million years ago A shrew like creature Was life hard living with dinosaurs?

First Flowering Plants 140 million years ago Highly diversified (250,000 species) and they had great success covering more ground than earlier plants

Dinosaurs go Extinct 65 million years ago The dinosaurs died out along with 50 % of the other life forms on Earth A meteor impact in the Gulf of Mexico Traces of Iridium are found at a distinct layer around the world

Mammals and flowering plants flourish 60 million years ago Mammals begin to grow in size Flowering species diversify even greater using their mammal friends to carry seeds to new areas

Beginning of Cascade volcanic arc 37 million years ago Along the coast of Western coast of North America The North American plate and the Juan De Fuca plate slam together at a snails pace

First primate in genus Homo 2.3 million years ago

First Homo Sapien 100,000 years ago

Human inhabit North America 60,000 years ago Land bridge

End of Last Ice Age 11,700 years ago