Is water really a requirement for life in other planets?

[Cordeline]

This is something that has been bothering me when my oldest brother and his friend suddenly started talking about their philosophy classes in high school and they started talking about evolution.

I am not very smart when it comes to these things, but I'm really curious so please bear with me, and correct me if I'm wrong in anything ~

My understanding of evolution is that living things adapt to different environments, some harsher than others. For example, a snake that lives in the forests somewhere in South America is different to a snake you can find in the desert in Africa. They have adapted to the different environments and if you switched their environments, they would die. But they all have a common ancestor which is some other snake. They "evolved" from this "parent" snake into something more specific for their environments. (I dunno if that makes sense? ><). Please correct me if I'm entirely wrong here ^-^ that's the way I understood it.

So wouldn't it be possible that some animals or any other living thing has adapted to live without water in another planet, or at least some that have adapted to live in the very harsh environments of other bodies in space? If we take into account that everything came from the Big Bang, wouldn't it be possible that some lifeforms have adapted to live in places with no water, and even more interesting, that they could be very, veeeeeery remotely linked to us? Or other lifeforms in our planet?

 

[Desinishon]

Evolution as you state is same as my mind. I don't know much about that though but your other question that's awesome thing you asked there...c: These are my opinion on your main question ....

Edit:

So wouldn't it be possible that some animals or any other living thing has adapted to live without water in another planet, or at least some that have adapted to live in the very harsh environments of other bodies in space?

There are several other factors with water which must take into account like energy, carbon or other miscellaneous factors.
Water......it's a universal solvent and damn stable one xD Enzymes need water, hell you're 70% made of water. In short water is life but duhhh that's not all....We have already been surprised a number of times by finding life in conditions on earth were we thought life could not possibly be. These lifeforms are called extremophiles. Let's take an example of them which is bacteria which not only survive but thrive in the high radiation environment inside nuclear reactors. They appear to "eat" radiation for sustenance.

Now to other question...
Life we know as in earth does need water. That's why we restricted ourselves to the conditions we know that support life like water to find other lifeforms in other planets. That's OK too but that doesn't mean there are not any other lifeform who may not live without water. Yeah i get that there might be a lifeform in other planet who might adapted to its environment but like I stated there are some other factors which must meet, only that way it's possible but who knows universe is full of surprises. we are searching for the planet with water in hope to habitat there. At least that's what I get it c:

 

[Kanzler]

If it evolves, it has to survive first. It wouldn't be out of the question that a novel environment would heavily select for features adaptive to it. If you could get an organism to survive on another planet, then all you have to do is wait and see, I guess.

 

[Shamol]

You're a very thoughtful individual, Cordeline.

There's no set definition for 'life', but at a very basic level, a living thing is basically a system that has found a way to work against the universe's entropy. The environment within a cell, for example, is in (apparent) violation of the second law of thermodynamics, seeing how there's a lot of internal order. This level of order is maintained by a steady supply of energy from the outside. This is the process we call metabolism- supply energy from without to retain the ordered state within.

So perhaps a minimal threshold any system has to pass before it can be considered life is- having a stable mechanism to harvest the environment's energy to retain some degree of organized complexity. As things stand today, there's simply no known way in which energy harvesting can be done without liquid water. I don't want to hand you a laundry list of why water is important for life's basic functioning, I think a quick google will get you covered.

Now one may think evolution can solve this problem, since it's all about creatures adopting to wherever they live. While evolution as a process has the same logic you mentioned, remember that it's not endlessly plastic. It still has to operate within the basic laws of the universe, especially the second law of thermodynamics.

Additionally, and crucially, the engine of natural selection (the process you described) gets to work only after you have a reproducing entity (say an RNA molecule), which is somewhat complex on its own. Only after you have multiple entities with differing reproducing rates would evolution start working, selecting the ones with more "fitness" and winnowing out the rest. This is why the pre-biotic origin of life research doesn't account for natural selection, because there's no reproducing entities at first to "select" to begin with, and instead the phenomenon is just called "chemical evolution". As Kanzler above has mentioned, a stage needs to be set before evolution can even enter the picture and be viable. But there's no known way in which the reactions basic to producing organized complexity can occur without water.