Life on Earth evolved in the ocean and it may have been "seeded" in the oceans but comets or meteors splashing into those ancient oceans. Life existed in the ocean for almost 3 billion years BEFORE it moved out on to land.
Respond to the following:
A) What might comets and/or meteors have had that might have "seeded" life in the oceans? (They did NOT bring whole organisms like bacteria).
B) What had to happen on Earth before life could move out of the oceans (the crust of the Earth had long since have cooled off).Hint it had to do with the conversion of the atmosphere due to photosynthesis.
Remember that life existed in the oceans for almost 3 billion years before it spread on to land (both plant and animal). Also PLANTS existed for about 2 billion years before the first animals evolved. Think about the biological differences between plants & animals and that is the key to this question.
Now with recent advances in astronomy especially the Hubble Space Telescope we now know of more planets OUTSIDE of our Solar System than the 8 inside the Solar System (sorry Pluto but you got downgraded). The current count is somewhere around 480 planets orbiting distant stars.
Now recently astronomers announced that they have discovered a "Goldielocks planet" orbiting a distant star. The term "Goldielocks" means that it is not too hot and not too cold to have liquid water thus it is just right to support life as we understand it. By now I hope you realize that LIFE can take many forms from viruses to elephants so do not always think in human or hominoid terms. Was Mars "Goldielocks" in the distant past when the Sun was hotter than it is now? We may find out someday. Also read the attached articles including the one about Jupiter's moon Europa that will give you some insight into this issue.