why?

fungel spores probaly are contaimination by what ever probe we sent there. any life evolving their would not be from any terrestrial evolutionary branch such as fungus

All this terror about "contaminating" other objects in the solar system with terran life is just misguided. We should all hope to get some terran life established on them.

Heck, we need to build probes full of selected terran extremophiles and spray them into the Martian atmosphere.

1. Any existing life there is, at this point, highly improbable

2. If there is any, how could terran life be competitive with it if the existing life has evolved to match the local environment over billions of years?

3. If there is existing life, how could a biologist not be able to easily distinguish it from terran life?

4. If the life there is ancient and now extinct, terran life isn't going to interfere with that

To answer part 2 with just one example: The native life of Mars, if it still exists, would exist in a state of homeostasis with its environment. It would have to in order to still remain existent. If terrestrial organisms were capable of replicating under martian conditions, they could easily eat everything up and then die off. Never quite getting the time necessary to adapt to the ecological limits of their new habitat. And by this process driving the native life to extinction as well.

To answer part 3: We're still discovering new kingdoms of life on Earth (though it's unlikely we'll discover new domains). If localized panspermia exists within our solar system (from meteor impacts or the like) it's possible martian life and terrestrial life are related enough for the martian life to fit within the already existing family tree of terrestrial life. https://astronomy.com/news/2021/05/did-life-on-earth-come-fr...

2. They'd never eat all of it. Also, it the distribution of either form will never be even across the planet. There will be "islands" of one or the other.

3. Biologists are easily able to determine if they are new kingdoms are not. They're also able to estimate how long ago divergence from a common root happened.

There are many, many examples of parallel evolution in terran biology, but none of them are confused with each other. It's absurdly unlikely that a terran modern amoeba will be confused with a Martian amoeba.

2) Localized sure, I wasn't arguing about the entire planet. But introduced life could drive the native life to a local extinction. And if it did so fast enough we would never know the local life had been there.

3) Yes, I know. While this isn't my specialty I work at an organization that does have people that specialize in this. The difficulty would be in definitively concluding whether this is a native divergence that we've just never seen before, or the result of Martian evolution.

2. We've found fossilized remnants of bacteria in rocks, haven't we? There's also ice on Mars. If life existed, we'd find it frozen in the ice.

3. A billion years of evolutionary divergence, with local alien adaptations, is going to be very hard to confuse with anything brought over by a probe.

I personally agree but was responding to the claim that finding fungal spores would mean we would necessarily turn mars into a nature reserve and not touch it. i pointed out the a fungal spore wouldn't be martin but earthly in origin

Declaring Mars a “nature reserve” would be completely unenforceable. Suppose you convince US Congress to pass a law banning Americans from sending humans to Mars, due to the risk of contamination to native Martian microbes. What happens when China says “now is our chance to show the world we’ve eclipsed the US by sending humans to Mars when they won’t“? Even though such a Chinese mission isn’t feasible today (an American one arguably isn’t either), who can say what its feasibility will be in another 20 or 50 years? And if not China, then sooner or later somebody else. Sustained global consensus on this issue is unlikely, which makes Mars as a “nature reserve” meaningless in the long-term. On Earth, the vast majority of nature reserves only exist because some government has military control of the territory and hence can enforce that status.

> Declaring Mars a “nature reserve” would be completely unenforceable.

Generally worked pretty well for Antarctica. A few research bases are permitted but colonization is internationally banned and not happening.

BTW, colonizing Antarctica would be a lot easier than colonizing Mars. Far fewer technical challenges to overcome, and much more practical experience overcoming those challenges.

Many people who call for Mars to be declared a "nature reserve" aren't just calling for a ban on Mars colonisation, they are calling on a ban on crewed exploration – either of the planet as a whole, or at least of sites they view as "environmentally sensitive" (which basically turns out to be the most interesting exploration targets, and many of the sites which would most easily host crews). They are worried about microbial contamination, which is a rather different environmental concern from Antarctica, and requires much stricter limits on human activity.

When someone like Elon Musk talks about "colonising" Mars, all he's realistically talking about – at first – is a crewed research station, so not that different from what we have in Antarctica. And many people who want Mars to be a "nature reserve" are opposed to even that. Yes, Musk hopes that such a research station will eventually grow into a buzzing metropolis, but I think if that ever happens it is a long way off. Musk might live to see crewed research stations established, I very much doubt he'll live to see genuine colonisation, much as he enjoys publicly fantasising about that topic.

Even the ban on colonising Antarctica only really works because it is banning something no government wants to do anyway. Crewed exploration of Mars would be attractive in principle to governments because of the benefits for national prestige, getting in the history-books, outshining the competition – the same basic reasons why the US went to the Moon. Of course, that benefit has to be weighed against the immense cost – but costs aren't constant, with further technological and economic developments it is going to become more affordable.

All the groundbreaking exploration opportunities with Antarctica have already been used up, so governments don't have the same motivations there. And I think the first human visit to another planet, is going to be much more noteworthy and prestigious and memorable, than whoever was first to explore some big freezing cold island on Earth. A thousand years from now, most people will still probably remember who Neil Armstrong was; I doubt many other people from the 20th century would still be household names (I suppose Einstein and Hitler would be the other likely candidates)–its only been a century or two, but the average person has no clue whom the first explorers of Antarctica were.