Life on Earth - Biology

By Kyara Young
  • Formation of Earth's Crust & Ocean (4.4 BYA)

    Formation of Earth's Crust & Ocean (4.4 BYA)

    Earth started cooling off which led to a crust forming and the creation of oceans. The oceans gave the conditions needed to develop life.
  • Evolution Of Prokaryotic Cells (3.8 BYA)

    Evolution Of Prokaryotic Cells (3.8 BYA)

    The first living organisms where prokaryotic cells. These organisms had no nucleus and where found in Earth's oceans at the time.
  • Earliest Evidence Of Life (3.7 BYA)

    Earliest Evidence Of Life (3.7 BYA)

    The earliest evidence of life was around 3.7 billion years ago, chemical signatures that were found in old rocks show activity from microscopic organisms.
  • First Fossil Evidence Stromatolites (3.5 BYA)

    First Fossil Evidence Stromatolites (3.5 BYA)

    Stromatolites are layered rock structures that were formed by microorganisms. These are known as the oldest fossils on Earth yet found.
  • Proliferation Of Cyanobacteria (2.7 BYA)

    Proliferation Of Cyanobacteria (2.7 BYA)

    Cyanobacteria spread all over the oceans around 2.7 billion years ago. They release oxygen to the atmosphere by the photosynthesis process.
  • Evolution of Eukaryotic Cells (2.1 BYA)

    Evolution of Eukaryotic Cells (2.1 BYA)

    These cells contain a nucleus and organelles and were likely formed by endosymbiosis.
  • Evolution Of Multicellular Organisms (1.2 BYA)

    Evolution Of Multicellular Organisms (1.2 BYA)

    Multicellular organisms evolved and they started working together, this made organisms more complex and helped them evolve faster.
  • Cambrian Explosion (541 MYA)

    Cambrian Explosion (541 MYA)

    The Cambrian Explosion occurred about 541 million years ago. It was due to increasing oxygen levels, and other changes, in this time many animal groups appeared in the fossil record.
  • First Land Plants (470 MYA)

    First Land Plants (470 MYA)

    The first land plants changed environments and it helped increase the oxygen levels on Earth, this happened around 470 million years ago.
  • Dinosaurs (230 MYA)

    Dinosaurs (230 MYA)

    Dinosaurs became the dominant animals on land around 230 million years ago, and lived around 165 million years before going extinct.