The history of life on earth Early Earth The earth is 4.5 billion years old. The earth's early atmosphere contained no oxygen. Methane Ammonia Hydrogen 3.8 billion years ago, the earliest form of life appeared on earth. Cyanobacteria are single-celled algae that are photosynthetic. Over hundreds of millions of years, cyanobacteria released oxygen into the atmosphere. - ozone - oxygen-breathing organisms
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The history of life on earth Early EarthThe earth is 4.5 billion years old. The earth's early atmosphere contained no oxygen. Methane
AmmoniaHydrogen
3.8 billion years ago, the earliest form of life appeared on earth.Cyanobacteria are single-celled algae that are photosynthetic.
Over hundreds of millions of years, cyanobacteria released oxygen into the atmosphere. - ozone- oxygen-breathing organisms
Invertebrates (simple animals without backbones) started to appear:- worms- jellies- corals
Then 544 million years ago, organisms with shells started to appear.
The first animals with backbones evolved. They lived in the ocean.
Ferns and mosses
Amphibians and reptiles start to appear
Early birds
Very small mammalsPlants evolved to be more complex -> gymnosperms
Small primateshominids
Angiosperms are the most complex of all plants Humans are the most complex
and intelligent of all animals
Write a 1 paragraph summary about how life came to be on earth.
Related Documents
