Sexual reproduction, genetic material from two parents, emerged as a fundamental evolutionary innovation of eukaryotes. The emergence of sexual reproduction in the Domain Eukaryota highlights the unique properties of eukaryotic cells. Eukaryotes have Complex Cell Structure, chromosomes within a nucleus, meiosis, a special type of cell division that reduces the chromosome number by half and creates genetic diversity, etc. This critical development enabled the mixing of genetic material, leading to increased genetic diversity and adaptability among early eukaryotic organisms, setting the stage for the complex tapestry of life that would eventually populate Earth.
- Domain: Eukaryota > Kingdom: Protista (protozoans and some algae)
(Later it evolved in the plantae and fungi kingdoms.)