Extinction is a natural process but with the expansion of the human race it is occurring at a excelling rate.
Its good to include thoughts, feelings, what was special about it..describe to the reader what it was like
A simile can be found when using "like" or "as" between two things. Example: I'm as happy as a clown.
Your question would be a metaphor. Both things are being compared to a science expieriment, probably meaning that they need to have an outcome, but it isn't known for sure if it will be a good or bad outcome.
Things like this can be taken many ways, so if you think something else, I'm sure it would work as well.
Odysseus in "The Odyssey" by Homer is a dynamic character.
