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History of life

Adapted from Wikipedia · Explorer experience

A colorful diagram showing the relationships between different groups of living things on Earth, with eukaryotes in red, archaea in green, and bacteria in blue.

The Amazing Story of Life on Earth

Life on Earth has a very long and interesting story. Our planet formed about 4.54 billion years ago, and very small living things began to grow soon after. The oldest signs of life are tiny fossils found in rocks from Greenland and Western Australia. These show that tiny organisms, like bacteria and archaea, were living more than 3 billion years ago in the oceans.

At first, most life was very small and lived in water. Some of these tiny organisms learned to make food from sunlight through a process called photosynthesis. This made lots of oxygen that helped more kinds of life to grow and change over time.

Later, special cells called eukaryotes appeared. These cells worked together to form multicellular organisms with many different kinds of cells. Plants began to grow on land, and animals with bodies that look the same on both sides, called Bilateria, also came along.

Sometimes, big events called mass extinctions changed what lived on Earth. After one of these events, new kinds of animals could grow and thrive. For example, after the time when dinosaurs were no longer alive, mammals became the main land animals.

Today, scientists think there could be many different kinds of tiny organisms all around Earth, even though we have only found and named a small part of all the species that have ever lived. The story of life is still being written, and there is so much more to discover!

Images

Ancient layered rocks formed by tiny ocean organisms in Shark Bay, Australia.
Illustrations of Darwin's finches, showcasing different bird species from the Galapagos Islands.
Magnified view of structures found in a meteorite, studied by scientists to explore possibilities of ancient microbial life.
Fossil impression of an ancient sea creature from the Ediacaran period.
Scientific illustration of Opabinia regalis, an interesting sea creature from the ancient Cambrian ocean.
Scientific drawing of Acanthodes bronni, an ancient fish-like creature from the Permian period.
A close-up photograph of lichens growing on a surface, showcasing their unique textures and colors in nature.
An artistic reconstruction of Cooksonia pertoni, one of the earliest known vascular plants from the Devonian period, showing its simple stem structure.
Illustration of Acanthostega, an ancient four-legged creature, showing its unique features and body structure.
A diagram showing the structure of a liposome, with water-attracting and water-repellent parts of molecules.
An ancient fossil illustration of Horodyskia, showing how it changed shape over time.
Scientists discovered that a slime mold can solve mazes by growing paths to reach food sources—this image shows how it connects to two sugar points with the shortest route.
A scenic view of the Gilboa region, likely featuring natural landscapes suitable for young readers.

This article is a child-friendly adaptation of the Wikipedia article on History of life, available under CC BY-SA 4.0.

Images from Wikimedia Commons. Tap any image to view credits and license.