PortalsOS

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.

Eukaryotes have larger genomes because they acquired mitochondria, which provided more energy to support larger genetic material. This energy availability allows for systematic gene maintenance, unlike bacteria that rely on lateral gene transfer.

The concept of extreme polyploidy in giant bacteria, where they possess tens of thousands of genome copies, highlights the immense energy demands compared to the efficiency of eukaryotic cells.

Bacterial evolution is fascinating because they maintain small genomes but have access to a large pan genome. For example, an E. coli cell might have 3,000 to 4,000 genes but access to 30,000 to 40,000 genes. This allows them to adapt by borrowing genes from other strains, which is crucial for survival in different environments.

The continuity between geological environments and cells suggests that life forms are continuous with Earth's geochemistry, challenging the idea of a 'Frankenstein moment' where life suddenly zaps into existence.

The necessity of large genomes in multicellular organisms is driven by the need to minimize genetic conflict between cells, ensuring that all cells work towards the same goal of survival and reproduction.

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 Asgard Archaea, discovered about ten years ago, are fascinating because they exhibit some eukaryotic-like features, such as similar proteins and genes, yet they remain fundamentally prokaryotic in complexity.

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.

Despite the vast number of planets, the unique development of eukaryotes on Earth suggests that while other methods of achieving complexity might exist, they are not easily realized in nature.