History of The Earth

Avery Shepherd

Earths Formation

When Earth was first formed the planet was a sea of molten rock. The Earth was very hot, the heat was brought by the repeated collisions of space rocks that clumped together as they collided to form this planet. As they began to gradually stop, Earth started to cool down. Clouds formed and storms started and continued, it rained for a very long time which flooded earth and created the oceans and seas we see today.

First life on Earth

The first life on Earth was about 3.8 billion years ago. It started with a single-celled bacteria. Only in the last 570 million years that arthropods began to evolve. After arthropods came fish about 530 million years ago. Plants came 475 million years ago . But surprisingly mammals themselves did not come into play until 200 million years ago. Humans have only been around 200,000 years. Humans have only been around for 0.004% of Earth's history.

The Earths Ice Age

Eighteen thousand years ago, the climate and ice age was extreme. In the beginning most of the Earths water began to freeze. There are five ice ages that have happened in earths history. The first ice age was over two billion years ago. Scientists study past ice ages by taking ice core samples, studying deep sea sediments, fossils, and landforms around the world.

The Jurrasic period

The Jurassic period started when the mass extinction happened in the Triassic. Life on earth quickly recovered. The Jurassic period is mostly known for its diversity of life. This period contained some of the worlds first birds and dinosaurs ever to live. The continents broke up making the Atlantic Ocean. The Atlantic Ocean has the worlds oldest ocean floor. All of the other sea floors have been recycled through the process called Plate Tectonics.

Snowball Earth :

When the Earth was entirely smothered in ice, stretching from the poles to the tropics it was called Snowball Earth. This time period happened 650 million years ago in the Pre-Cambrian period. But now many researchers thought that there may have been more times then this once that the Earth was a giant snowball. How long they lasted still varies, but when Earth was this giant snowball, life could only live where sunlight managed to go through the ice to allow photosynthesis.

Flood basalt eruptions

Flood basalt eruptions are just a longer and more extreme type of volcanic activity. These eruptions may continue to erupt for thousand- millions of years and the lava would cover thousands of kilometers. The huge volume of lava is also with a similar release of volcanic gases that include sulphur dioxide and carbon dioxide. These large amounts of lava and gases affect climate and may also cause acid rain, leading to mass extinctions.

Desert Earth :

A desert was formed when the supercontinent of Pangaea straddled the equator and stretched to the poles. In the North East the coastal areas along with the North and South poles had lots of water although other parts of the deserts had no water.

Coal Forests :

When the Carboniferous period ended, seas started to drain away leaving coastal plains covered with swampy forests. They had a dense and lush vegetation. Even though the plants were much different, the coal forests were much like prone rainforests, mangrove swamps and cypress swamps in many ways. When plants had fallen into the water they did not decay. Although they will become coal.

Asteroid Impacts :

In the 1980s there was an asteroid that hit Earth leading to the Extinction of dinosaurs. Asteroids can range from a radius of 25-186 miles. Scientists have estimated that almost 70 asteroids the same or bigger in size have hit the Earth 1.8 billion years ago to 3.8 billion years ago. The evidence for the impacts are from tiny droplets called spherules in the Earths rock layers. They were once molten droplets that were sent into space inside the huge plumes which were created by the impacts on Earth. When they fell back to earth they created a layers of sediment called spherule beds.

Extinction of the Mammoth :

One major extinction is the Mammoth. They died out 10,000 years ago. The two main reason of its extinction are climate change, humans, and meteorites and comets.
Scientists think that they have found evidence of an asteroid that hit the Earth, which led to the extinction of large animals, including the woolly mammoth , this resulted in a large climate change.
This made the Earth start to heat up making it to much for the Mammoth to live in.
The humans contributed to the extinction because they hunted to Mammoths. The mixture of the climate quickly changing and humans hunting them they died out pretty quickly.

Citations


Works Cited

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