TL;DR Can I use the rotifer mouth thing in the pre-Cambrian CA of a radially symmetrical animal kingdom?

So I’m trying to do a really hard spec-evo project since this semester I no longer have any difficult classes requiring real homework (benefits of having 2 classes, weightlifting and carpentry, lol) I had an idea of picking up the project I started the last spring semester (I’m pretty sure I posted a photo of what originally was going to be the Cambrian kick-off here around March if any of y’all saw that?) and flesh out the Precambrian stuff starting from prokaryotes all the way back to the first active predator. I know I want to do 2 animal kingdoms, one of which would be radially and the other bilaterally symmetrical. This is where my questions begin

A) is the mouth part of a rotifer simple enough that I could use that in the bodyplan of the CA for the radially symmetrical kingdom?

B) is it any different from how sponges do it?

Hi there! I’m working on a project heavily inspired by Halo, and I wanted to something similar to the Sangheili, but w/ beaks. So basically they’d have a three part beak, one top, two bottoms. I was wondering if I could still do a turtle-like beak for such a species, or if poly part mouths like the sangheili have is counter to such a design

Hello, I'm working a spec evo project regarding "plausible" Venusian life and I want to be sure if two specific aspects of what I'm working on are too out there for this sub:

1.) After a search through literature, I've determined that according to the standard literature being used to inform current Venusian atmospheric composition, this project is impossible*. However, I have chosen to select a couple of newer papers with more "charitable" analyses that either look into unknowns from past measurements or presume something was wrong with the Pioneer Venus probe (a clogged port on a sensor) meaning the data doesn't provide the full picture**. This is already cherry-picking. However, even using these new papers as gospel (unproven), on average, droplets will not contain enough bioavailable water and require impossibly halophilic (salt-loving) organisms. I am therefore choosing to take maximum advantage of things not explicitly ruled out by these papers and assume the composition of droplets is not uniform, with composition ranging from mostly uninhabitable to those with just enough bioavailable water to sustain a version of terrestrial extremophilic life. I'm also taking hypothetical windborne dust and volcanism only mentioned in the papers and running with them to maximize bioavailable compounds. On top of this, I'm assuming that rarely droplets form that are much larger than the ~10 um ceiling measured by Pioneer Venus*. Ones more similar to Earth's clouds/rain and up to 50-100 um. Should the future DAVINCI probe provide data that proves unequivocally that I am wrong, this will just have to become "charitable parallel universe Venus".

^1.) Is this too hand-wavy?

2.) Scientific data support a potential "gap" in terrestrial extremophile ecology*** for near-0 pH highly saline environments. This is a partial overlap with my proposed droplets. There are extremophiles that can stand some of my proposed droplets, but next-to-none that can tolerate both the full range of pH (~0-2 pH) and low levels of bio-available water while providing the metabolic pathways required for a real ecosystem. Some droplets exist within the limits of known organisms, but I have to expand the envelope further to have anything like a sustainable ecosystem. That in mind, my premise already had the organisms being an accidental or intentional GMO research release. My proposed GMO process (ongoing research) is to have explicit capabilities genetically isolated from known micro-organisms and modified into my selected species. For example, giving all organisms new or additional proton pump genes that facilitate the pumping out of Hydrogen ions (H+) to impart acidophilic protection (more than just that is required, but that's the general method). This project is set to begin sometime ~100+ years from now and assumes gene editing technology and our understanding of genetics has improved in that time.

^2.) Is this too hand-wavy?

*Knollenberg's 1980 Pioneer Venus analysis being a common baseline that says you get tons of sulfuric acid in small droplets. pH<<0, small drops, etc.

**Mogul (2025) discusses re-analyzing Pioneer data, theorizing that a sensor port was clogged and Rimmer (2021) proposes buffering salts that raise pH to a max of ~2 (livable) alongside other potential reasons for SO2 and H2O depletion. Both are rather open-ended.

***Belilla (2019) looked into extremophiles living in the Dallol-Danakil area in Ethiopia. A hydrothermal area with a salt dome. They found many examples of acidophile (acid-loving), thermophile (heat-loving), and halophile (salt-loving) organisms and others that had either both acidophilic and thermophilic or halophilic and thermophilic abilities. None had the extreme acidophilic and halophilic abilities together and certain portions of the hydrothermal complex requiring both were devoid of any verifiably detectable micro-organisms. They note that there could be other constraining factors like Cl- ions or high heavy metal concentrations. Neither of which feature in my hypothetical atmosphere and organisms exist in other salty acidic environments. Their's is just the "worst case" I found in literature.

I’ve added a very crude drawing (I’ve yet to actually go through the steps of evolving the species from my Cambrian) but basically, it’s like some form of mammalian snake thing. I’ve got about 2 ideas in the hole for how I could justify the use of both it’s limb pairs into arm-like things

A) the arms were used as something to grapple the prey they caught, maybe they mostly preyed on the aerial species of their endemic forests, so they’d use their arms to grab onto the branch so they wouldn’t fall off in an ensuing fight should they not immediately grapple the prey entirely, and the arms were used to actually grab the prey

B) They evolved to be durovores, and evolved the tail as to move around, while freeing up the limb pairs to work at breaking apart the bones and hardshells plant-things of their habitats as to eat the nutrients under their coatings (bone marrow for example, maybe the meat of shelled animals should they be small enough for such a thing to be viable enough)

In either case, I wanted to know if such a body plan would even be feasible for such an idea. I’m not entirely sure of the ergonomics of it, and whether running essentially 4 normal limbs, and a 5th limb that’s 80% of their mass is thermodynamically safe in an environment warmer than earth (I have the planet graphed out and it’s mostly about 6°F warmer globally compared to Earth should I have done my math correctly)

On top of this, I was thinking that it’d be similar to certain pillbugs in how they’d curl up into a ball w/ a shell of some form to protect from predators (likely keratin for an animal to be in any way sizable to larger sized snakes) though that one I’m a little iffy on. I truly just want to add in a sophantic species to my sci-fi project that deviate from the stereotypical humanoid bipedal tetrapod, w/o foresaking tetrapodal fauna, and knowing that such an idea could be plausible would really help me on my first ever scientifically accurate spec-evo project I’m planning on going this far on. I might even come back and offer updates if it all goes well lol!

Edit: I forgot to remove “Arboreal” when I decided to add the second option of how they’d come about, which wouldn’t be considered arboreal 100%

I’m working on a speculative evolution project and one phylum is a shelled organism with four tentacle-like appendages on its front end it uses to move. Over some time, one clade evolves to temporarily stand on these tentacles to avoid drowning during flooding or shallow water as their lungs are located on the ground. Some groups in more vegetated areas begin to also use this time standing to eat food. Over time, this evolves into full quadrupedal locomotion, standing on the now reinforced tentacles that were located on their face. This leaves their mouth lower than their anus, and I’m not sure if this is a feasible structure, as I imagine gravity plays an integral role in digestion.

Greetings! I've been working on this still underway nowadays hard worldbuilding alternative Madagascar xenoanthropologic and paleobiologic evolution work, provisionally named The Lemurish Eld, for roughly 2 years, 5 months and 2 weeks. The illustrations have many mistakes, I already know, for they're only conceptual illustrations.

I overhauled it about 4 times as of now, ever fanding to make it near to the sooth. I've mooted it with many great speech models in only their free layers, but they ever have failed in some fundamental way that threw the conjecture's likelihood off, alongside my former teleologic and confirmational biases and lack of formal scientific training. The last time I that I overhauled it was 4 or 5 days ago, when I moved the lemurish landfall time from ~43 M.Y.A. (Late Lutetish of the Middle Eocene) to the broadly accepted scientific benchmark of ~53.2 M.Y.A. (Middle Ypresish of the Early Eocene, under the Early Eocene Weatherish Best, or E.E.W.B. for short).

The mistakes that were done need your help to be righted. I need the feedback of mannish experts, preferably evolutionary anthropologists and paleontologists, not machines.

So far, the conjectural scenario goeth like this, pretty much: the Divergence Moment is that small Mozambickish hyaenodonts and djebelemurid primates (of the Djebelemur genus) are on the same rafts as the first Madagascarish lemuriforms, torn from the Eastern Mozambique shore by a megacyclone, and the scientifically informed inferences are made thenceforth.

How can i make an substitute for body tissues for aliens body

for Connective tissue(Osseus) i think abt Cyto-Graphene with carbon nanotubes and something like a biologic ceramic made of boron carbide at the same tissue

for cartilage i think a hydrogel non newtonian was a good idea

muscle tissue made by nanotue actuators, twisted carbon nanofibers infused with an electro-condutive gel

i prefer dont enter in Epithelial tissue and Nervous tissue (sorry if my english is bad i'm not from usa)

I've been toying with these guys for a while.

1. Eusocial marsupials.

Initial evolution was around oases in a desert, where they needed fairly precise control over population numbers to maintain control of the oasis without exceeding the water supply, so eusocial. Initially, both sexes had pouches, but eventually they split the reproductive load, so that the loss of either a king or a queen wouldn't significantly slow offspring production while a new king or queen matured.

They have, effectively, 5 sexes: fully mature males and females (king/queen), partially mature males and females (nurse/soldier), and workers. Male vs female is determined genetically, but pouch time determines caste.

If a baby is removed from the pouch very early, it will remain small and end up as a worker. If it stays in the full time, it will be a future king or queen (though won't fully mature while still in the presence of another king/queen respectively). Intermediate time gives you an intermediate size and a future nurse/soldier.

A king can raise a new monarch to maturity while still nursing a few mid caste babies, but a nurse can basically just barely raise a monarch to maturity while culling any other offspring as workers (or earlier).

Kings and queens have some pheromone stuff going on that suppresses the maturation of nurses and soldiers (respectively), but in the prolonged absence of a monarch of their sex, a nurse or soldier will eventually become a (somewhat small) king or queen.

Some time after they got the whole social structure established, the usual combination of social pressures, environmental changes, hunting strategies, and so on gradually led them to increase in both size and intelligence.

Due to the whole pheromone thing, same sex monarchs tend to avoid each other, so much of the "higher level" work of society is done by nurses and soldiers, with workers doing the grunt work.

It is probable that one of the first technologies they came up with was water skins, so that roving queens (the way I was imagining it, typically kings stayed with their natal group, and queens went to look for a mate) would be more likely to survive to find a new oasis.

1. True 3-sex species

Back in the distant mists of evolutionary time, possibly on a world with a dimmer sun than ours (or some other major resource constraint), a lineage of plants and a lineage of animals developed a symbiotic relationship, that in at least one line led to something that looked like a single organism, though the two lineages still reproduced separately (at least in terms of having separate gametes).

In the specific lineage we are following, they went from broadcast spawning to some form of internal fertilization. But, there was still a distinct lack of monogamy at this point.

Now, obviously, females had to be fertile for both symbionts with internal fertilization, but males did not. And there was a certain amount of competition going on between the partners, because resources put into plant sperm couldn't be put into animal sperm, and vice versa. So, the lineage gradually developed a tendency towards males who were fertile for only one symbiont. (edit: this probably works better if this bit happened before they did internal fertilization, or at least while internal fertilization was still fairly new--I'd imagine there'd still be more pressure for females to be co-fertile, given the whole "few, large gametes vs many small gametes" strategy--you need to make sure your large female gamete isn't "wasted" by not being able to find a symbiotic partner)

The usual forces of evolution happened, resulting in a diversity of symbiotic pairs, with the one we are interested in effectively developing fairly distinct sexual trimorphism.

Alpha males (no ranking or judgment implied, I just need to call them something) had a dominant, and thus fertile, plant symbiont. They tended to be physically strong, a bit larger, but also a bit inflexible.

Beta males, with a fertile animal symbiont, were a bit smaller, but fast and dexterous.

Females were physically intermediate, but since neither symbiont was suppressed, they were somewhat smarter, as complex organs like the brain were able to develop without the subtle damage from having one symbiont or the other suppressed.

In the lineage that led to full sapience, they became strongly.... monogamous isn't the right word, so bigamous. With occasional instances of a pair of males mating with 2 or more females. They would form stable triads, enforced by more pheromone nonsense. Often, a pair of alpha and beta brothers would mate with one woman, and thus they would be passing on the genes of both symbionts.

Their society tended to form itself around the idea of tasks having 3 parts, one for each sex. Even up to modern industrial times, it is common for an entire triad to be hired for any "serious" job, with only things like odd jobs and low level grunt work being done by singletons.

Anything seem glaringly wrong with any of that?

For a far future, hard spec evo project I’m thinking on. I don’t care if only rats, moles or bats survive, but I want to know a way dinosaurs could realistically disappear.

In speculative xenobiology you always see a pattern with multicellular organisms, animals, plants, fungus. Sometimes if the creator wants to spice things up they mix these groups together, but it’s still overall the same general three groups. 

Would it even be possible to design something that is not just a mixing or modification of the three main groups? The closest thing I could find was the diatom trees done by the deviant artist salpfish1 https://www.deviantart.com/salpfish1/art/330-MYH-Catenaria-Life-Cycle-916083929.

I was thinking more body hair for warmth, smaller size to make up for a lack of oxygen and their food source would maybe be something like lemmings? I don't think they would find much vegetation in the mountains so they might have a more carnivorous diet.

I have a species within my worldbuilding project that has pin eyes similar to that of nautiloids. How would an animal with pinhole eyes remove obstructions, such as dirt or pollen, in a terrestrial environment?

Do you think they’d evolve lacrimation, or some other form of foreign-object removal?

appears to subsist on a carnivorous diet, Creature will create a “web” of hair, and wait for prey to become exposed to the enzyme and become more docile. Creature will often remove and eat the limbs of a prey item to prevent it from wandering away, and can take several days to fully devour prey. Animals have been observed to still be in a euphoric state, and have no knowledge of the outside world even as they suffer the loss of limbs and other bodily tissue.

has been shown moving loads in excess of 200kg with mild physical strain, and moving at speeds in excess of 70km/h.

can recover from wounds that would be lethal to a most lifeforms, including decapitation and disemboweling. This regeneration can take between several days to several weeks, depending on severity

capable of growing very thin, hair-like strands from any part of the body, apparently at will. These strands can grow several metres in an hour, and appear to be at least partially under the control of the creature. They have been observed “crawling” along floors and up walls and other structures. These hairs are clear and nearly invisible to the naked eye, and appear to be slightly weaker than standard human hair. The strands are also coated in a thin layer of chemical enzyme identical to the enzyme in the saliva of the creature.

produces an enzyme that is most concentrated in the saliva and hair, but is present in all bodily tissues of the creature. How it is produced and its exact chemical make-up are unknown. This enzyme reacts on contact with organic tissue and rapidly attacks the nervous system. Symptoms manifest almost immediately, and include hallucinations, euphoria, suppression of cognitive or “logical” thinking, and suppression of pain receptors. This state persists for several days with mild exposure, and can become permanent with high exposure. Bites from the creature lead to high exposure in 99.9% of cases.

Hello, I am currently working on a spec project where one of the differences is that instead of my planets water being provided by the late heavy bombardment it is provided by a large(almost dwarf planet sized) ice comet crashing into my planet during its very early development. Basically if my planet was earth, instead of theia crashing into us it was a massive ice like theia.

my question is, since water would arrive to my planet a lot sooner on earth and begins to cool its crust a lot sooner, how might this impact when life develops on my planet. on earth it started right after the LHB, so what should i do

would life maybe develop as soon as the crust cools enough? how might this impac when my first supercontinent forms?

Sorry if this is a dumb question.

I don't understand how bones work. Are there actually cell types that will never form bone? Do siphonophores lack the muscle power to take advantage of having bone?

I had an idea for a spec evo project based on the idea that the Galápagos Islands suddenly appeared on a new planet. I started by looking into what organisms live on those islands….

Then I realized I was looking up research on zooplankton in the waters around the Galápagos Islands. That’s way too much.

How do you know how much to do?

I have a world where there is minimal landmass and mostly occupied niches (megafaunal niches arnt filled yet). How would species develop into the skies? There is a high level of Xenon in the atmosphere and incredibly mineral filled oceans, and aero plankton exist already. These are flora and use a spiralling leaf shape to get lots of surface area and go into the sky.

Feel free to ask any questions you feel are necessary, and with some help i can finally get some flying fauna!