As I’ve discussed here before, writers who want to ground their fiction in science have a limited amount of biology to draw from. We only have one planet with life to study, and have yet to meet an alien. Still, a fair bit of biology is grounded in physics and chemistry. Any extraterrestrial life is almost certainly going to be made of the same elements we are, and will likely have both genetic material and some way to exchange that material between individuals when reproducing.
One of the latest such efforts is taking samples from Antarctic lakes that have been covered with ice for thousands of years, like Lake Vida. This lake is salty, and is deeply buried under ice. It has been isolated for nearly 3,000 years. And yet, it is full of bacteria. They’re still being studied, but these bacteria probably live on hydrogen: they’re completely isolated from the things that most living things get their energy from (sunlight, especially).
And then there’s Lake Vostok. This Antarctic lake is sealed under 4,000 m of ice, and has been cut off from the rest of the world for 15 to 25 million years. Drilling through that much ice safely and without contaminating the lake is a huge undertaking, and has taken years. The Russian scientists aren’t just looking for life: bubbles trapped in the ice provide invaluable information about past atmospheric composition, for instance. It’s a good thing that they’re producing all sorts of data, since no life has been found yet.
We don’t know the less-hospitable corners of our own planet all that well (Mars is better mapped than Earth, because we don’t know a whole lot about the deep ocean). Exploring at home will help us better understand what we find as we get out into the rest of the solar system, and will let us add some science to our fiction.