Given the way certain other threads are going, this looks more like intellectual arrogance on the part of taxonomists (“Well, of course OUR way is self-evidently the right way”). As a certain other member of the Forums likes to point out, “We see things not as they are, but as we are.”
Humans define invasive species as follows:
- non-native (or alien) to the ecosystem under consideration and,
- whose introduction causes or is likely to cause economic or environmental harm or harm to human [or alien] health.
So as long as those criteria are met by the incoming humans, the aliens would consider us invasive. There are many species on earth that fit criteria 1, but not 2 and are not considered invasive. We can’t always predict if criteria 2 will occur until after the fact.
Whether it’s within the rights of the aliens to try to stop us from visiting or settling their lands is a political question not an ecological one. It’s probably best that we not engage in political discussions in this forum. But to continue without hopefully not going too far, I think most humans are OK with the idea of us humans having the right to try to prevent an alien invasion of Earth–and I hope that humans can see this from the alien’s perspective and not attempt to invade their homeland.
Only if taxonomy does not reflect an underlying reality. Will aliens think the sky is blue? Is it arrogant to think that they would? No. We can measure the spectrum and see that it is 450–485 nm. This isn’t our perspective or biased opinion, it’s the reality. Likewise, if life evolved (primarily) as bifurcating lineages (as much of life has), then they’d almost certainly classify things based on this real pattern–rather than grouping dragon flies and birds together because they fly. Humans passed through a time when we didn’t know as much as we know now and did classify things differently (whales being fish not mammals for example). I’m assuming that these aliens know at least as much as we do. If they are unfamiliar with evolution, then I think they’d probably lump whales in with the fishes!).
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The question of whether we might carry pathogens to which aliens might have no immunity is not really a political one but a biological one.
Absolutely! But we can’t know if that will or won’t happen which is why it would be best to not make physical contact without a considerable amount of information. But you were talking about “rights” which are political. It is wise for people or aliens to consider it their right to not be contacted by outsiders–for many reasons (ecological/disease impacts being one).
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Ah. I think you live somewhere other than where I do, so you may associate that word differently than I do.
Bolding mine.
Yes, rights are a concept argued among people with different political affiliations and motives. Different groups of people consider rights differently–certainly aliens would also. The Borg are a good (fictional) example. Here’s a real-world example: https://www.marketplace.org/2022/09/28/british-walkers-demand-wider-right-to-roam/ relevant to iNatters. It would sure be nice if I had the right to roam!
I have no politics or motive (?) here to leave behind, so need no reminder. I was discussing the topic as inspired by The Martian Chronicles and other works by Ray Bradbury.
Please assume good intent.
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No bad intent assumed! I just wanted to avoid going down a political rabbit hole. Keeping on topic, aliens would be wise to classify humans as a potential threat–in part due to pathogens. But if these aliens are not protein-based as we are, it’s probably unlikely that our pathogens could interact with their bodies (plants don’t have to worry about catching human diseases because we are so different from them). Still, the concern is valid!
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Oh, i get what you are saying about humans being invasive if we colonize other planets with life on them. That’s a really interesting question and gets addressed some in SciFi, in some stories earth life isn’t compatible with a parallel ecology and can’t eat or be eaten by it which somewhat blunts the effect. There’s also stories like Kim Stanley Robinson’s mars series where there is a group of people who feel terraforming even a lifeless planet is a form of invasive or unethical behavior. I think it’s a really interesting question and IS worth discussing if we can avoid the politics (which is unlikely here) because we are already at the point where we have potentially spread life to Mars. We haven’t demonstrated success in sterilizing our space probes, and we have determined Mars has an environment that could support at least some Earth extremophiles so it’s actually possible we have already introduced life, and it’s also quite possible there is already native extremophile microorganisms there. So it could have already happened and if it hasn’t it probably will soon. We also introduced tardigrades to the moon and while it seems very unlikely they could reproduce and spread there, i guess there’s some argument one could make that it is possible. And it appears very likely that some of the ice moons’ internal environment could support life from earth, and probably multicellular life in some cases.
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I disagree. The variations among organisms are real. Various different human cultures do classify organisms the same general way taxonomists do (for groups they try to classify completely). I would expect alien biologists to search for and see those same real variations that western taxonomist do, that New Guinea tribesmen do, that native Central American tribes do.
That doesn’t mean all the classifications would be the same. Whales as odd fish rather than odd mammals? Entirely plausible, though it’s also plausible the alien biologists would switch them to the odd mammals category if they got to know whales well. They would no doubt classify organisms in practical but arbitrary (i.e., non-phylogenetic) ways, such as flying organisms, blue organisms, nitrogen fixers, animals only women and children collect, edible plants, flowers that smell good, organisms that fluoresce in UV, etc., but those categories would be in addition to recognizing the kinds and phylogenetic groups we name. They might find different ranks worth naming, perhaps emphasizing what we call orders or families rather than species. And if they classify the species, they might well, probably would, recognize species somewhat differently than we do, lumping or splitting more.
I think aliens would fail to recognize the taxonomic categories we do only if they just failed to perceive earthly organisms. Maybe if they recognize only conscious plasmas as organisms, they would classify all earthly organisms as rock scum, for example. But if they are interested in earthly organisms and want to classify them, they have to deal with the reality we also deal with.
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Anthropomorphizing what hypothetical sentient aliens think probably has the same (if not bigger) pitfalls as anthropomorphizing what non-human animals think. ;-)
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This made my mind ping!
Background: OK: There is one short story by Bradbury wherein the plants on Venus grow so quickly that the human men have to keep walking. If they stop, the plants grow tentacle like around their ankles and can pull them down and hold them down, conceivably to their demise. (Because I live where I do, I think of this story often during our rainy season when I see how quickly vines grow especially.)
Now combine that with Venus flytraps or other carnivorous plants.
PING: I wonder if aliens who took plant forms could become infected from consuming proteins (any earth proteins) with pathogens, much like we can get foodborne illnesses.
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Any alien civilization advanced enough to be capable of space travel would understand genetics and classify terran lifeforms fundamentally the same way we do.
Classifying organisms by their appearance was just the best people could do when their understanding of biology was still primitive.
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natural selection should be a constant anywhere there is life that meets our criteria of reproducing and having traits of its predecessor (if you agree to that criteria) but genetics could work a whole lot of different ways and i don’t think it’s a given that genetics and heritance like that on Earth would exist for all aliens. Look how differently the reproductive cylces of fungi, plants, and animals work. Many fungi don’t even really seem to have well defined species, whereas many animals do (give or take arguing that definition). I also suspect evolutionary convergence is also a universal force and if the aliens come from an earth-like planet they will probably have very similar forms to ours, such as cactus-like plants, things that fly like birds or bats, crab creatures (that form seems to evolve in parallel a lot), tree-like organisms with narrow photosynthetic entities that shed snow, etc etc. So i think they might be interested in genetic ancestry but also have a sort of parallel taxonomy based on form, especially if they are space naturalists who are interested in flying around space and studying the different ecologies on different planet types. Which is what i’d want to do if i were an alien with a warp drive, and i imagine many others here would as well :)
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They would be very good at classifying fungi because they’re the ones that brought them here 
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Aliens certainly would notice examples of convergent evolution! They might give earthly organisms names that reflect the similarity to their alien cactus, etc. However, they would not mistake our earthly species for the ones on their original planet. (Similar though fish are to whales and spiny Euphorbs to cactuses, these groups are easy enough to distinguish in detail and I’m sure alien organisms would also differ from similar Earthly forms.) The aliens would be interested in form – and they would understand something of the genetics that lie behind those forms. I imagine their classification system would rely on both, as is ours, but when they’re doing a quick preliminary survey, their classification would be based on form.
Whether alien genetics would have to be based on ribonucleic and deoxyribonucleic acids is not known (assuming carbon-based life, which is likely but perhaps not the only option). Nonetheless I think we can be certain that advanced aliens would be the product of evolutionary processes like we see here, based on fairly stable stable genetic materials. Therefore, it’s likely than aliens able to reach us would have something like sexual reproduction. It’s very likely that they would have one gender contributing to the offspring little beyond genetics and the other contributing both genetics and food. Why do I think so? (1) Having only asexual reproduction doesn’t work in the long run because of the accumulation of defective genes (though it’s possible the advanced aliens had long ago figured out technological ways to repair their genes). (2) Widespread genetic exchange, as seen in bacteria, is probably incompatible with the need for precisely fitting gene products in complex organisms. (3) Mathematical modelling of possible breeding systems suggest that systems with more than two sexes are unstable, liable to be invaded by simpler, two-sex systems. (I don’t consider the multiple mating strains found in some fungi to be equivalent to multiple sexes, but it’s possible I should.)
Nothing in the above is intended to deny the reality that humans (and perhaps advanced aliens) perceive gender in multiple ways, not confined to just two categories. The above refers only to gametes that combine to produce zygotes.
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