Fraser Cain discusses panspermia  : Is Life On Mars Related To Life On Earth? – Universe Today

The planet is hostile to life now, but evidence is mounting that it was once a warm and habitable world, with rivers, lakes and oceans. Mars could have vast reserves of subsurface water, where life could thrive even now.

If we did discover life there, it’s possible that it’s completely unrelated to Earth life. This would demonstrate that life can originate on almost any world, with the right conditions.

It’s also possible that life on Mars is related to Earth, and our two planets share a common ancestor billions of years in the past.

This is a theory called panspermia.