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The nucleous of the planet could be pretty hot and provide enough energy for a stustainable life. If the nucleous of the planet contains a enough radioactive materials, it could continue producing heating for billions of years, enough to allow the formation of a complex life. The main problem is that there could be no photosynthesis, so no oxygen, or ...


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There are many benefits to being large*, that is why large size has evolved so many times, the real reason insects to day are not large is because they can't get that big without drastically changing their anatomy, in particular their breathing mechanism which is very size limited. At larger sizes spiracle/tracheal breathing just can't exchange much oxygen ...


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Welcome to the stack! Great question! The core of the planet would still be quite hot, meaning that volcanoes and underwater vents could occasionally release hot (and therefore high-energy) bursts of liquid/gas into the environment. Perhaps this could be harnessed, somehow...? This is the most likely answer, and it's occurring right here on Earth as we ...


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You can get around the problem by getting your geckos to evolve human-like hands with more dexterity, and lose the Van der Wall forces. Since they're filling the niches formerly occupied by humans and other large animals, that would mean they're now more land based. This can create an evolutionary pressure towards hands with dexterity over hands that let ...


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There are two ways to go about handling this problem - one that keeps van der Waals forces and the other that loses it. As you've pointed out van der Waals (more like van der Walls) forces help geckos stick to walls. What this force is is basically an attraction formed due to the polarity between two surfaces (i.e the gecko and the surface of the wall). Now ...


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Before asking why insects would grow bigger, a better question to ask would be why would anything grow bigger or smaller. A great answer for this can be found here. Now from that link one will find that insects benefit from being small because it's just so beneficial for them - literally every answer on that list applies (except for hibernation and ...


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If being larger afforded an insect greater availability of food it would create an evolutionary pressure that favors larger insects. This pressure would be most present in times of food shortage, perhaps droughts or flooding. Being larger could also make it favorable in terms of the insect being able to defend itself or its territory. Evolution is fairly ...


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First of all, keep in mind that without drastic changes in the atmospheric composition, insects won't grow much bigger than they are today, because oxygen availability practically limits their size. That apart, an obvious reason for an insect to grow bigger is because it has to face bigger enemies. Say a wasp preys on flies. If some flies randomly happen to ...


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Evert their gills. https://www.youtube.com/watch?v=Scr6xSIG-Vo Octopi have gills they use for oxygen exchange. They are delicate so they are kept inside the mantle. They can push them out of the mantle to rinse them out - everting them. That is what this octopus is doing. The silvery thing is its gill. On prolonged landwalks your cephalopods evert ...


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Symbiotic Relationships They have a friendly pet or plant that stores concentrated oxygen, or highly-oxygenated water, into a bladder. Your octopus carries the bladder, or a bandolier of them. The octopus must wear a water-containing mask over their gills (perhaps another over their eyes), and diffuse the oxygen into the water before attempting to breathe ...


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Some fish, such as Betta Splendens (Betta fish), have what are called a Labyrinth organ that allows them to breath air. Its how they survive low oxygen environments when trapped in small, shallow ponds. When oxygen is low, they pop up to the surface and take a breath. Its not a true substitute for lungs (they can't stay out of water forever), but its a ...


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Lungs. Crustaceans and arachnids have managed to evolve lungs directly from gills, unlike tetrapods in which the primitive gill structures are homologous to various structural features in tetrapod skulls, and cephalopods could conceivably do the same. The most significant innovation would be a means to keep the mantle chamber housing the gills inflated out ...


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Maybe you can "design" some type of symbiotic relationship with corals, in which the liverwort/moss provide food or some kind or structural guide to them (or something else), and the dead corals would provide the structure for the moss and corals to reach enough sunlight. As time passes, the top levels of the "forest" would block the sunlight and make the ...


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Bryophitic plants do have specialised organs - just not vascular ones, and given no competition they would quickly become non-bryophitic. They do already have much in similar with aquatic plants - however the definition of 'Bryophitic' is simply that they do not have vascular mechanisms (ie. they do not transport nutrients from a soil). This would indeed ...


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Among mammal species, there are a small percentage with bodies large enough to support large brains. Among mammal species with bodies large enough to support large brains, a minority do have large brains, brain comparable to human brains in size. That leaves about a hundred or so species of mammals on Earth with brains, and possibly intelligence levels, ...


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Since your query specifies a civilised species, rather than a species possessing intelligence, awareness, soul, imagination and the like, I'd posit that such species already exist. Or are very close to it. A civilised species should have, according to human definition, a highly developed society or culture; refinement in taste and manners; or evidence of ...


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Some type of monkey, likely an ape (since they're better on the brain front). But it's not just brains that you need. I don't think it's possible to overestimate how important hands are for our civilization. Boiled down far enough, any tangible result of science is just advanced tool use, and our hands are unmissable for how we are doing that. Almost as ...


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In short term (millions of years), most likely already long living, somewhat intelligent and social species with free hand-like manipulators. In longer term (hundred of millions years), pretty much anything can change. So, in order of decreasing probability: Genetically engineered (uplifted) animals with hands. Monkeys, apes, maybe hamsters, ferrets, ...


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I think next pretender would be some ape, orangutan maybe. They some of necessary things to create something of civilization. Apes have dexterous hands, quite big brain, can use tools, have social lives. On Earth we have also other smart and/or social animals, but most of them lack something essential. For example dolphins are very smart, but their fins and ...


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You need creatures that can see color. Mammals as a group are basically colorblind. Only some primates and monotremes can see a decent range of color, everything else is either dichromatic or monochromatic, which in humans we refer to as being colorblind. So your "mammals" need to be able to see color. for earth mammals green, red, yellow, and orange are ...


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It may help to look at how animals are coloured here on earth. Many herbivorous mammals' coats are camouflage as a result of evolution. Think of a gazelle or a zebra, or insects, or even many small birds. If the Flora is brightly coloured, so would the Fauna that eat it. Another reason we see bright colours in real life are as a warning to stay away. ...


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Evolution is a random and uncaring monster, nothing is inevitable and everything is possible, so it's entirely possible that vibrant colours could have evolved in mammals. The most obvious possible cause is Amotz Zahavi's Handicap Principle. It benefits neither prey nor predator species to be brightly coloured, but this handicap would be a costly signal ...


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My understanding of evolution on (this) Earth is that the mammals we see today, evolved from small, nocturnal animals, which had found success in a niche where they could hide from the dominant group: the dinosaurs, whereas birds are dinosaurs; the ones that survived the big meteor strike 65 million years ago. Going further back, what became the mammals ...


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You cannot. There is no way an extraterrestrial creature to be classified as a mammal.


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"Bright" is often not a good survival characteristic for land animals. Ideally you want lack of predators. Of course, some mammals are predators so you may need to prevent their evolution/arrival in that environment. Fisherian Runaway is a good way to explain the evolutionary process; in fact it is why peacocks evolved such ornate displays. The theory rests ...


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It's a photosynthetic organism with very efficient pigments. They have to be because the organism is a bipedal animal without leaves, not even elephant's ears. The efficiency comes at a price, and the price is being tuned to narrow spectral ranges. When their skin is under the correct illumination it will convert carbon, water and light into glicose, the ...


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If the things that prey on mammals have poor color vision, then color is not a major problem for the mammals to adopt. So make the top-tier predators be colorblind reptiles. Next, you need something to drive the color. Imagine if species had lots of recessive genes that we’re really bad to pair up, and imagine that those traits were correlated with color. In ...


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If we want it to be realistic, there is no way. This is result of few factors: The solar radiation on the earth in the upper atmosphere (before it is reduced by atmospheric effects and clouds) is 1300 W/m^2. Human body surface is 1.9 m^2, and at least 1/2 of it will be facing away from the sun. Then following that the shape of your body will reduce the ...


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Clearly you're talking about a photosynthetic organism, albeit one with very precise responses to different wavelengths. My suggestion would be a creature that evolved on a planet orbiting a ternary star system, where the wavelength of sunlight changes dramatically in a cycle with a period of months of years, and which has evolved such that this cycle ...


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Other answers have described the various evolutionary reasons why coloration evolves such as sexual selection and aposematism. However, mammals already have these evolutionary pressures driving the evolution of dramatic appearances and many mammals do have highly conspicuous appearances. Why then do mammals not use bright colors to make their appearances ...


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Birds and Reptiles usually develop colorful displays for mating purposes. The general concept is that the colors denote exceptional health of the individual (usually the male). In some cases, like the Peacock, the display actually suits no functional evolution purpose other than showing off to the female that, in addition to being suited to live in it's ...


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Mating selectivity Color vision of mammals is good enough to appreciate things like a peacock's tail. And that's the possible mechanism. Female selectivity of male display. Mister Hopeful has colorful hair, maybe colorful skin markings. And he struts and displays them to attract the attention of Miss Prospective. The guy with the most colorful markings ...


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Start with an discretionary omnivorous apex predator with good color vision and an instinctive appreciation for vibrant colors and contrast. If this predator was sentient, we would call its effect on the environment, "selective breeding", but since it is not sentient, this predator's preferences are comparable to the preferences of pollinating insects for ...


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How could I make an evolutionary pathway that leads to that happening? Sounds like you already answered your own question, right here: most mammals don't have good enough color vision for it to have real evolutionary value. Mammals probably lost two of their four cone cell types waaaay back in the time of the dinosaurs, for as-yet unknown reasons, but ...


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I can see a few factors that would encourage that trait : a lack of predators: without the need to run and hide from predators, animals can afford to have flashier colors that makes them easier to spot Alternatively, perhaps the colors, while appearing flashy to us, blend in quite well with the equally colorful flora present. Continuing the adaptation to ...


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Well we humans are pretty much mammals and even thought it's not through (biological) evolution we started to dye our hair in different colors. Perhaps you are able to find an evolutionary reasoning in that? Like standing out to find a mate? Also an option would be a plant based one, certain sloths for example have a greenish appearance through moss ...


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I guess the thing with non-colorful mammals is they typically don't have ways to escape easily like birds or insects from predators, so they have to rely more on sneaking and hiding, and this would be a natural reason to not be very distinguished with colored fur. Therefore ecosystems where mammals don't have to fear being eaten nor need to sneak to their ...


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I am thinking, longer fingers, stronger backs as already mentioned in the answers above. A tail for balancing would go a long way as well.


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Females might get around more. In general, females of any species invest more energy in offspring than males. Eggs require more resource investment than sperm. This is true for pollinators too. If a female needs more energy, it must go get it. Assuming pollinators are visiting flowers for food, a female might visit more flowers than a male: it needs ...


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Ultimately, the answer you seek lies in Enzymes. These are essentially biological catalysts that greatly increase the rate of specific biochemical reactions in the body. Tie this to a hormone, like Estrogen (which is found in greater levels in females) and you have a biological catalyst that may only occur in female pollinators. The mechanism would be that ...


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I think you should clarify whether you mean "without MAKING tools" versus "without USING tools". There are a LOT of intelligent animals that use 'found' tools including primates, birds, and even octopus. If the question is "can you be sapient without USING tools", I think that's extremely unlikely, and would be possible with a creature that doesn't have ...


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I would probably turn that question around, why would a sapient intelligent species not use tools if they have the capacity to make them. Tools are not a necessity for intelligence (or sapiens), though it's an inevitable outcome of intelligence. Any entity with the mental capacity to shape the world around it to it's own benefit, will invariably do so ...


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Unlikely, but Plausible My first reaction was no, because use of tools is one of the ways we define intelligence. For example with logical thinking and knowledge of cause and effect you can reason that hitting something with a pointy stick is better than punching them. However, your question was not about using tools, but making them. So in order for this ...


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Only if they are two separate life cycles and the transition brings advantages. The juvenile could be like a caterpilar: not particularly mobile but great at building bulk. It would be hard to hatch gigantic (you would need equally gigantic eggs and egg-layers) but maybe it takes up water quickly after being born and surpasses their parents within a week or ...


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No Or, more correctly, it violates the laws of evolution as we understand it. There are tradeoffs that are made for offspring in nature. The general rule is that the quicker it takes for a creature to develop, the less complex it can be. A fly, for instance, is capable of all fly behavior within 24 hours, give or take, but fly behavior is very simplistic. ...


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The shores would be mostly sand and tiny shards of broken glass, because A) any sand underwater during the lightning era wouldn't have turned into glass, and B) erosion would have pulverized all the glass on the shores, and weathered them down to tiny bits of sea glass. Contrary to your premise, most of the terrain would probably be sand mixed with chunks of ...


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So, apologies in advance but this will be a negative answer. Normally I'd flag this sort of question as far too broad, but realistically your premise is for a world that's either going to turn back to a terrestrial state (and so you can just look at the history of life on earth) or will remain so hideously inhospitable that surface life likely won't exist. ...


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Two-headed creatures - or even humans - are not unknown in reality, and have even been known to survive to adulthood, so as a point mutation it is not beyond the bounds of possibility for it to occur over a very short period relative to the typical evolutionary timescale. In order for this condition to persist across generations, there are several pre-...


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Two thoughts: First, there's no particular reason that the brain needs to be located in the head. Such a creature could have a single brain located in the body cavity, in which case the 'heads' would be little more than sensory extensions, allowing it to see, speak, and smell in different directions simultaneously. The heads would appear to act ...


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No difference. Evolution does notwork on such short timescales. Jews have been cutting off their foreskins for thousands of years yet each new generation gets born with them again. Unless an extremely specific mutation randomly appears in the population, AND that mutation conveys a large benefit to the chances of breeding, AND the breeding successfully ...


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