Life

[High Lord Tolkien]

These are general observable comments.
I know there's life deep in the oceans and far up into the atmosphere but nothing to compare to the "jackpot" range I'm about to speak about.
There's also no exact measurements here either, so no nitpicking!

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I'm amazed at the tiny sliver of range where life exists on Earth.
Look at the trees and realize that there's not much life above them.
Lets say an average height of a tree is 60 meters (around 200 ft)
From the tallest mountain to the lowest valley there's not much life above the tree tops.
Not much above the 200 ft range.
That's less than the length of a football field.


The oceans allow for more depth but not that much.
Look at the oceans and realize that after you go down 200 meters the abundance of life diminishes.
200 meters (around 650feet)

From space, relative to the size of Earth, life is less than a film of moisture on a basketball.
That's it.

It's amazing.

[Vraith]

Never thought about that..interesting..and leads me to my own amazements...the variety within that narrow band, and the extreme conditions life CAN survive in, beyond the narrow band...[literally true: you can't make this up...there are things [very small things, completely unrelated to very small rocks that float] adapted and living in nuclear waste...

[Xar]

I wouldn't say the band is so narrow... just because there are no macroscopic creatures living in the high atmosphere doesn't mean it's unlikely there might be bacteria or other such microorganisms there, for example. And as for the oceans, there is life - even large organisms - living much deeper than 200 m: take for the example the Fangtooth fish, which lives at a depth between 200 m and 2000 m; or the deep sea angler, living between 1000 m and 2000 m of depth; or the famous giant squid, known to live at least around 900 m of depth. I could go on with this for quite a while, but I guess you get the idea - there's life down there the likes of which we probably can't even imagine yet. Every year, oceanologists continue discovering new and wondrous species.

And even within the "narrow band" you thought of, there are creatures living in environments we would find inhospitable. They recently found bacteria in a pocket of seawater deep into Arctic ice, where it had remained buried for millennia, for example; there are bacteria capable of living within sulfuric hot springs (thermophiles), and macroscopic organisms adapted to live near hot thermal vents beneath the ocean. And there are even bacteria capable of resisting a whole lot of stuff: introducing the deinococcus radiodurans, a polyextremophile capable of enduring cold, dehydration, heat, vacuum, acid and radiation at levels which would kill any other animal. Its radiation resistance in particular is of great interest to microbiologists, and it has been studied extensively. This little guy can survive up to 10,000 Greys (Gy) of radiation with little or no side effects, whereas a human would die if exposed to 10 Gy.

Even insects - such as the common beetle - can endure conditions which would kill vertebrates: some beetles can survive up to 1,000 Gy of radiation, for example.

In short, life is much more varied than most of us believe, and much more resistant to being wiped out as well

EDIT: Just for fun, did you know that there are immortal creatures in the world? I'm not talking about bacteria, but actual multicellular organisms which can live indefinitely, unless killed? Hydra (a small freshwater animal) has been suggested to be one such creature, and there is a jellyfish (Turritopsis Nutricola, if I remember correctly) which can rejuvenate itself during or after sexual contact, and can undergo infinite cycles of growing older - rejuvenating - growing older - rejuvenating, effectively being immortal.