Were Eukaryotic Cells the First Cells?

The first eukaryotic cells - cells with a nucleus an internal membrane-bound organelles - probably evolved about 2 billion years ago. This is explained by the endosymbiotic theory

. ... The small cells were not digested by the large cells. Instead, they lived within the large cells and evolved into organelles.

Were the first cells prokaryotic or eukaryotic?

The first cells were most likely very simple prokaryotic forms. Ra- diometric dating indicates that the earth is 4 to 5 billion years old and that prokaryotes may have arisen more than 3.5 billion years ago. Eukaryotes are thought to have first appeared about 1.5 billion years ago.

What were the 1st cells?

The first cells consisted of little more than an organic molecule such as RNA inside a lipid membrane. One cell (or group of cells), called the last universal common ancestor (LUCA), gave rise to all subsequent life on Earth. Photosynthesis evolved by 3 billion years ago and released oxygen into the atmosphere.