Researchers believe they've discovered the oldest known evidence of life on Earth. Scientists found signs of biological activity in 3.95 billion-year-old rocks from Labrador in northeast Canada. The rock samples were formed when Earth was 500 million years old.

See the source article by following the link below:
Researchers believe they've discovered the oldest known evidence of life on Earth. Scientists found signs of biological activity in 3.95 billion-year-old rocks from Labrador in northeast Canada. The rock samples were formed when Earth was 500 million years old.