In the beginning, God created the Heavens and the Earth (time + force = space + matter), he later created humans. This was widely regarded as a bad move, and even God regretted it (Genesis 6:6), but that's later. We're talking about the beginning right now. So bada-bada-boom, animals + land + humans *loud cheering noises*.
Humans were immortal back in those days, and by humans I meant Adam and Eve, and by immortal I mean immortal. They could never die of old age, all of their injuries healed extraordinarily quickly, and they were living peaceful lives. Then Adam and Eve decided to eat this fruit which probably had some sort of virus in it because it made them be able to die of old age (at the time, old age was like 1,000 years). If you want to blame someone because you're not immortal, blame Eve, she listened to that serpent who apparently had legs.
THIS IS WHY YOU LISTEN TO GOD. Also there was this tree called the tree of life but God buried it in the flood, if you ever find it, don't eat it. Eating that is worse that eating a moldy cheese off of a cafeteria floor, think about it, if that cheese which is only a few months old tastes bad, what would something created during the beginning of time taste like? (Bad)
Anyways, something happened later with these two dudes named Cain and Abel, one killed the other (CAIN KILLED ABEL) and fled to somewhere else. The next part is important, because it is probably the reason why I'm ugly, it's either this or because I eat too much but I'm pretty sure it's the former. So Adam and Eve didn't only have 2 children, they had tons, and since they were the only humans that God created, it meant that Cain did *The Thing* with one of his sisters.
The humans that CAIN and his wife borne became pretty smart. They created stuff, like cities, boats, things you would expect before 1760. Most of them lived to be 900 years or older unless they were dumb enough to fight a dinosaur, I call those Ancient Russians. They probably had some sort of ancient vodka seeing as they had a pretty sophisticated society.
A few years later God got angry because all of the humans were doing evil literally all the time except for one family, so he destroyed everything with a flood, and Noah & his family survived
And thus began The Beginning.
TL;DR?
Humans were made, big mistake.