There are many kinds of creatures that lived on Earth long ago and their relatives still exist today. We know about them from fossil records, imprints or remains that we find in rock.
While these living things have been around a long time, there is one organism that has outlasted pretty much all others. It is so small you would likely need a microscope to see it: cyanobacteria.
I learned about these long-lived bacteria from my friend Michael Berger, clinical assistant professor of the School of Biological sciences at Washington State University Vancouver.
Berger studies barnacles, which have been on the planet for about 500 million years. He told me that cyanobacteria have been around even longer than barnacles.
One of the oldest fossil records of cyanobacteria was found in Australia. It was nearly 2.7 billion years old. For a bit of perspective, that was way before dinosaurs roamed the earth between 230 and 65 million years ago.