The canonical position for most adverbs is after the verb phrase, i.e. the verb and any object(s):
Coco runs fast.
Carla speaks Russian fluently. (Russian = object)
He discredited the company and its CEO intentionally. (after verb and two objects)
However, there are adverbs that are more idiomatic -or- have a different meaning in front of the verb. In your example, first before the verb, means initially, whereas first after the verb phrase means before another person or thing.
I first met Hank when he moved here from Texas. (=our initial meeting)
I met Hank first, when he moved here from Texas. (=I was the first
person to meet him -or- I met him before I met anyone else)
In another example, quickly has different meanings in these positions:
I quickly switched the files in my bosses office. (= not wasting
I switched the files in my bosses office quickly. (= with rapid
To answer your question, based on the above, sentences (1) and (3) are possible, however (2) isn't grammatical. To paraphrase them:
(1) Ever since the moment when life initially appeared on Earth...
(2) [this is an outdated syntax for "first," but not ungrammatical]
(3) Given that life appeared on Earth before any other place...
Naturally, some adverbs can also occur at the beginning of the sentence or practically any position for that matter, e.g. sometimes, whereas others have syntactic strictures regarding their position and must be studied individually.
Sometimes I just close my eyes and shut out the world.
I sometimes just close my eyes and shut out the world.
I close my eyes sometimes and just shut out the world.
I just close my eyes and shut out the world sometimes.