Cells come from pre-existing cells through the process of cell division, a fundamental principle of cell theory established in the 19th century. This means that every new cell arises by the splitting of an existing cell
. Regarding the very first cells on Earth, they originated about 3.5 to 4 billion years ago from simpler precursors called protocells. These early protocells were likely vesicles of organic molecules and RNA-like substances capable of self-replication and catalytic functions. Over time, these evolved into the first true cells, which were prokaryotic in nature (bacteria and archaea)
. Eukaryotic cells, which have a nucleus and more complex internal structures, arose later (around 2 billion years ago) through a symbiotic event where one primitive cell engulfed another, leading to organelles like mitochondria. This event marked a major evolutionary step toward complex multicellular life
. In summary:
- All current cells come from division of existing cells
- The first cells evolved from protocells formed by organic molecules and RNA-like material around 4 billion years ago
- Complex eukaryotic cells emerged later via symbiosis between simpler cells
Thus, cells originate from a continuous lineage starting with the earliest self-replicating protocells on the primordial Earth.
