Did Life on Earth Come From Mars?
Given the same raw materials, Mars would have been a better host for life to arise than Earth, which some scientists believe was too flooded for the chemistry of life to gain a toehold. Without at least occasional dry land, the chemistry needed to get life started doesn’t work very well because the molecules to support genetics, such as RNA, are chemically unstable in many ways, particularly in water.
Scientists who model what early Earth was like believe the planet had no dry spots. On the other hand Mars is believed to have had liquid surface water in the past, albeit never in the amounts found on Earth. Rocks from Mars regularly fall onto the surface of Earth, providing a possible transport mechanism between the two worlds.