On earth there are many species of animals with varying degrees of intelligence. In the past there were several species of intelligent anthropoids. All evolved from a common source. The animals and plants too, evolved from a common source.
Experiments have shown that given the earth’s original atmosphere of carbon dioxide, methane, water vapor, ammonia, hydrogen sulfide and a source of energy such as lightning, solar radiation, hot rocks or maybe even radiation from other stars then complex molecules such as amino acids will be created and interact.
Given enough time and enough interactions simple forms of life may be created. The first would find conditions very hostile today and would quickly be consumed. In their time, however, there was no competition and a soup of food they could feed on. Here was your common source.
The sun and our solar system are probably very ordinary. Probably very common in the Universe which has an uncountable number of such similar systems. If a planet is the right distance from it’s sun for water vapor to condense to liquid water and is big enough to retain an atmosphere then it’s almost inevitable that life may be produced. Such life will evolve. Life may also evolve on planets which are very different to our own. It may even evolve using liquid ammonia instead of water. Perhaps life may even evolve in the atmosphere of some stars!
Wherever life evolves it will face multiple challenges. Extinction Level Events (ELE) such as impacts, solar flares, nearby supernovas, and now we've detected black hole collisions which are even more violent. All may kill life off but the process will start again. In some cases intelligent life may evolve and be lucky enough to survive long enough to ask this same question.
