text: Actually it is 4.6 billion years ago that the Earth formed. Life began 3.8 Billion years ago in teh precambrian period. Oldest prokaryote fossils were found 3.5 billion years ago. Oldest eukaryotes fossils are 2.2 billion years old. Invertabrates and algae sprouted about 600 million years ago. Bony fish and insects became abundant 409 million years ago. Dinaussaurs developed 245 million years ago and died 65 million years ago. The primate group developed 35-23 million years agi abd our apelike ancestors developed 5-million years ago (according to estimates). HIumans became abundant in diversification during the ice age 1.8 million years ago.