PortalsOS

Eukaryotes are significant because they represent a singularity in the history of life on Earth, arising once about 2 billion years ago. This event gave rise to all complex life, despite bacteria and archaea having a greater genetic repertoire.

The adaptation of cells to internal selection pressures, rather than external environments, may explain why single-celled algae and complex multicellular organisms share similar cellular structures.

The difficulty of successful endosymbiosis, where one cell engulfs another, is a significant barrier to complexity. While this may have occurred many times, it often fails, leading to the loss of the endosymbiont.

Nick Lane argues that life on other planets is likely to be carbon-based and water-dependent due to the commonality of these elements. He suggests that out of a thousand planets with life, 999 might follow this pattern, with only one being radically different.

The emergence of eukaryotes is seen as a major bottleneck in the development of complex life. Despite the vast number of planets that could potentially give rise to eukaryotes, it seems this event is incredibly rare, with Earth being a unique example.

The fundamental bottleneck in the evolution of life is not the transition from geochemistry to early life, but rather the development from nucleotides to RNA, DNA, and ribosomes. This suggests that early life forms could be common, but complex life is less so.