Earthlings (humans) are mostly similar to humans in real life. The only difference is that they didn’t entirely evolve from monkeys but from the common ancestors of Martians, Venusians and Jovians. However, they did mingle with neanderthals, which did evolve from monkeys.
Earthlings anywhere that isn’t planet Earth: Earthlings are the weakest when it comes to change in planets. They are more likely to face health problems from both weaker and stronger gravitational pull, and need liquid water to survive which is something that none of the planets have (Mars has ice, Jupiter has water vapor, and Venus has no water at all). Their life spans, instead of being decreased by a couple years on a planet, get decreased to a mere couple of minutes at best. They cannot survive on Jupiter or Venus due to the atmosphere, and can barely get by on Mars. The only benefit they have compared to the other aliens is that they may be a little smarter compared to the others.