Question: how did we get on the earth

Jared Parnell answered on 11 Mar 2015:

That is a good question, and a hard one to answer. One theory is that the right chemicals were on the planet, and these began to slosh together and from more complex chemicals, and these began to connect and at some point life began from this chemical mess!

It is hard to say, if that is true then we assume that this early life slowly began adapting to the environment, evolving from bacteria to small organisms to fish to lizards, and so on. Evolution is a very complicated process and no-one really knows where it began!