When did the first eukaryotes emerge on Earth?

The emergence of the first eukaryotes on Earth is generally estimated to have occurred around 2 billion years ago. This timeframe is supported by various lines of evidence, including fossil records and molecular data that suggest a significant shift in biological complexity during this period. Eukaryotes, which are characterized by their complex cell structures, including a defined nucleus and organelles, represent a crucial step in the evolution of life. The development of these organisms is often linked to significant environmental changes and the proliferation of oxygen in the atmosphere, a process largely driven by photosynthetic organisms. This evolutionary milestone laid the groundwork for the development of multicellular organisms and the vast diversity of life forms that followed.