<Tr> <Td> 1400 Ma </Td> <Td> Great increase in stromatolite diversity . </Td> </Tr> <Tr> <Td> By 1200 Ma </Td> <Td> Meiosis and sexual reproduction are present in single - celled eukaryotes, and possibly in the common ancestor of all eukaryotes . Sex may even have arisen earlier in the RNA world . Sexual reproduction first appears in the fossil records; it may have increased the rate of evolution . </Td> </Tr> <Tr> <Td> 800 Ma </Td> <Td> First multicellular organism may have arisen . </Td> </Tr> <Tr> <Td> 750 Ma </Td> <Td> First protozoa (ex: Melanocyrillium) </Td> </Tr>

About how long ago did multicellular life forms appear on earth