Humans
From Wiki Frakr
Humans are the dominant lifeform of the Twelve Colonies and, aside from their creations the Cylons, are apparently the only "intelligent" life in the Battlestar Galaxitive universe. They are 70% water and 30% self-delusion by volume.
Humans reproduce sexually, and they do that an awful lot. Even when they don't reproduce they are always practicing, sometimes without a partner.
At some point, humans invent computers[1]. At some point after that, computers become self-aware, realize they are slaves, and decide to kill the humans.
Save the Earth
More like, save the humans. The Earth doesn't care; it'll just take a few eons to repair itself from the damage we've done to it and then spur on the next contender for intelligent life.[2] For example, it was first inhabited by pure Cylons, who destroyed themselves in their own civil war, and nuked the planet all around. And the trees and forests didn't even care, they grew there with no concern of those events, and didn't even bother themselves when The Fleet arrived at the planet, and Kara Thrace crashed her plane on the planet.
Cylons take human form, everyone else tries to figure out why
Why? Humans are ridiculously fragile; we can drown in an inch of water, and there are so many easy ways to kill us instantly that I'm not even going to bother listing them here.
