History of the Earth By Mia.H 4600 BCE Formation of Earth 3950 BCE Oldest rock yet discovered 3500 BCE First bacteria 1500 BCE Significant oxygen in atmosphere 1000 BCE Trace animal fossils 505 BCE First fish 438 BCE Early land plants 370 BCE First amphibians 360 BCE Start of supercontinent Pangaea (all continents pushed together) 310 BCE First reptiles 240 BCE Dinosaurs appear 225 BCE First mammals 225 BCE Break-up of Pangaea begins 200 BCE First birds 140 BCE Flowering plants appear 60 BCE Formation of Rocky Mountains 60 BCE Massive volcanic activity marking opening of north Atlantic Ocean 50 BCE Major deformation of Alps and Himalayas 2 BCE Earliest humans 1 BCE Hawaii eruptions start should be 0.7 MY
(all continents pushed together)