1500 – 1400 million years ago

Year thirty-two
Eukaryotes

Eukaryotes

The oldest fossil eukaryotes are found in the Bitter Springs Formation, Australia.

Fossil eukaryotes have been found in rocks that formed when Earth was 32 (about 1400 million years ago).

They were a lot bigger than the earliest bacteria, but still only about one tenth of a millimetre long and still made of just a single cell, although a more complicated one. They could only survive when there was enough oxygen in the water. The cell contains lots of organelles, which are minute bodies that control the mechanisms within the organism such as energy, photosynthesis and movement. Organelles may have started out as individual prokaryotes (more primitive cells) that invaded the cell of another organism and began to live together as one organism.

Lipids, possibly indicating the first eukaryotes, have been found in rocks that were formed around Earth's 19th birthday (2700 million years ago). However, no fossil eukaryotes have been found in rocks older than the Earth's 32nd birthday.

Prokaryotes multiplied by simple division of the cell. Eukaryotes multiplied in a different way. First the cell would split into two, then into four or more, each piece floating away in the sea water. When two pieces met, they joined together to form the new generation. Plants and animals (including us) were eventually to evolve from the eukaryotes.


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