Ck 12: Life Science: Origins of Life

[Free Registration/Login may be required to access all resource tools.] There is good evidence that life has probably existed on Earth for most of Earth's history. Fossils of blue-green algae found in Australia are the oldest fossils of life forms on Earth. They are at least 3.5 billion years old. Learn more about the origins of life in this learning module produced by CK-12.