It is clear from fossils that simple organisms dominated life on Earth for the first 3 billion years. The first multicellular organisms started showing up on Earth about a billion years ago. As time went on, life forms became increasingly complex. And last but not least, the Cambrian period brought more complexity and diversity to animals.
Documentary Film – First Complex Life
History of Earth’s Complex Life Forms
The history of life on Earth tells the story of the processes by which living organisms have evolved. This is from the origin of life on Earth some 4.4 billion years ago to the incredible diversity present in today’s organisms.
Additionally, global catastrophes, climatic changes, and the joining and separation of continents and oceans all affect their development.
The similarities between all present-day organisms indicate the existence of a universal common ancestor from which all known species have diverged through evolutionary processes.
Frequently asked questions
What is the most complex form of life?
The microscopic water flea (Daphnia pulex) is the most complex organism on Earth. It’s the first crustacean whose genome has ever been sequenced. What makes it so unusual? On average, it has about 31,000 genes compared to ours.
What were the first living cells?
3.7 billion years ago, microscopic organisms left traces of their presence in rocks. These signals are made of a type of carbon molecule produced by living things.
There’s also evidence of microbes in the dense structures they made (“stromatolites“). Some of these structures are 3.5 billion years old. Stromatolites are formed by microbes trapping sediment and binding it into layers.
As the microbes die, minerals precipitate inside the layers, forming durable structures. Earth’s earliest life forms can be better understood by studying today’s rare stromatolite reefs.
First living things were probably unicellular, prokaryotic, anaerobic, and possessed a simple structure. On the other hand, the most accepted hypothesis for eukaryotic cells is endosymbiosis.
