The History of The Universe

By: Haniah Virk and Isha Dixit

The Big Bang Theory

The Big Bang Theory was first created in the yer 1927 by Georges Lemaitre. According to the standard theory the Big Bang theory occurred around 13.7 billion years ago. Many people believe that the Big Bang was an explosion but some scientists like to explain it as an expansion of the universe.

Formation of the First Cells

The first cells were formed on Earth around 3.7 million years ago. They are known as prokaryotic cells or cells without a true nucleus. These cells do not have a membrane around the nucleus and are found in organisms such as bacteria.

Oxygen Levels

Initially Earth didn't have much oxygen (also known as anoxic) but as cells began to form and as these cells began to form organisms such as plants and animals began to appear as well. When these plants appeared they began going through a process called photosynthesis which is what plants go through to create their food. As they do this they give out oxygen. This cause the oxygen levels on Earth to increase rapidly.

Cambrian Explosion

The Cambrian Explosion occurred around 535 million years ago. This "explosion" is referred to the time period where most of the animal phyla began to appear. They call it an explosion because one minute there were only a couple of animals and the next tons of animals begin to appear out of nowhere.

Evolution of Homo Sapiens

Humans belong to the species of homo sapiens. Homo sapiens began to evolve around 200,000 years ago. Many people say that homo sapiens began evolving in the continent of Africa. As they evolved they began to spread to different continents and pick up on different lifestyles.