The photos, which are the finalists in the Academy's first-ever photography contest, show everything from a mid-air attack between a hawk and a jay to an ocean wave that looks like a snow-capped mountain.
The Academy received more than 6,000 entries from around the world.
"They're images of places that you might not go or animals or behaviors that you might not ordinarily see. It really makes you consider your role in the natural world," California Academy of Sciences Creative Director Rhonda Rubinstein said.
The grand prize winner, a photo titled "The Luckiest Penguin," shows a penguin in the Antarctic narrowly escaping a hungry leopard seal.
The winners will be awarded Thursday night at the Academy's nightlife event.