Metamorphosis and Ontogenesis

Since these topics include quite a few important questions about the design of the Multicellular and especially the Aware Stage, I figured it would be best to open a new thread to discuss this here, since the last discussion of this matter didn’t cover everything I had in mind.

As we all know, metamorphosis describes a drastic change in the anatomy and occupied niche of an animal during the transition from larval to adult form in the life cycle of an animal. This is of course a fascinating aspect of biology to explore and would not only increase the realism of the simulation, but also offer the player an opportunity to experience very different play styles during the life of a single organism (e.g. playing as a scavenging aquatic larval form, focused on hiding and avoiding danger, and then transition to a predatory aerial organism, focused on mobility and active hunting). I personally think that different stages of metamorphosis could very well be implemented by tweaking the caste system a bit, and allowing an organism to occupy different castes at different times and chronologically progress through them (probably via a pupation event, that the player can trigger after gathering enough resources).

However, this begs another question: How do you properly simulate the ontogenesis of organisms, that do not go through metamorphosis? Intuitively, you would start as just a smaller version of the adult form, with lower stats and capacity to hold food and gradually grow into a full fledged adult. But this would obviously be a gross oversimplification, since proportions and behaviour of an animal often change drastically during their lifetime (e.g. Tyrannosaurus probably showed ontogenetic niche partitioning, which means that juveniles were built for hunting different animals than adults and were built accordingly (longer legs, weaker muscles in neck and jaw, for hunting smaller, more agile prey), to not compete directly with the adults).

What would be the best way to properly implement these factors into the aware stage? You could theoretically choose which tissues to prioritize during character growth in the editor, but this might involve some very frustrating finetuning, so you don’t overprioritize on tissue a bit too much during a certain age and end up with an organism with an unviable stage in his life cycle, just because you pulled a slider a bit too far. Similar problems arise with the behavioral editor, since obviously juveniles should act differently than adults and might need to hide from animals that their parents would hunt without a second thought. For this it might be enough to add a few if-conditions to the logic gates, e.g. “IF size/age below X, AND encounter with animal Y, THEN run etc.”, but I might be overlooking stuff.

That would be all from me for now, I am looking forward to your thoughts on the matter.


I hope that if you play as a cocooned individual of your species you can skip the time in the cocoon or increase the rate of time moving.

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I think that this feature should be handled similarly to sexual dimorphism and eusocial castes - and I propose for a new addition to this concept: the species should be edited as a neuter adult first and foremost.
Any form differences between males and females or something different, as well as children and adults, would be added onto the default of the species. This means you could evolve the species as a whole and synchronize changes between forms. This would also allow smooth transitions as an individual grows.
Different life cycles would obviously change how your species can develop. Eggs are cheap, but can only develop an organism so far - mechanically, they have a low maximum complexity. Gestation will allow a more complex organism to be formed at birth, but will strain the mother for a relatively long amount of time. A cocoon will allow radical morphological changes to be made, as caterpillars turn everything but their brain to mush in order to self-gestate.
Butterfly life cycles are very interesting and specialized, and would be nice to see in Thrive.

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Pupation only makes sense for ecdysozoa, and other things that shed their skin. There should also be gradually transformation from one form to another (or perhaps you could have both in the same creature)

The classification into ecdysozoa and other organisms becomes kind of meaningless, when you consider that thrive will evolve a complete ecosystem from scratch without phyla and groups similar to earth. I would imagine a choice between different kinds of metamorphic transitions between the stages, connected with different boni and mali, similar to the choice between the membranes in the microbe stage. E.g. cocooning might require an additional resource for building the cocoon and take longer, but offer a larger degree of change at once, while metamorphosis via multiple successive moults might be faster, but only allow gradual change (maybe via limiting the amount of MP, that may be used to change the different castes/life stages from each other) and require more stages to reach the adult form.

And gradual transformation should obviously be included into the game, probably even as default, due to its intuitive nature, but the design problems I mentioned in the initial post about it still remain. Unless you have ideas to tackle these issues, in which case I would be happy to hear them.

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I was refering in general to ecdysozoon-like creatures, like how the word ‘humanoid’ is often used. Also, many insects pupate without using a cocoon, and a few even continue to move around as a pupa.

Perhaps a creature that doesn’t shed skin could evolve to create a temporary covering in order to pupate? And finally, a pupa is not necessary, as a creature could transform inside the larva, and then emerge. Perhaps the larva could recover, and then have another adult develop inside.

Would a partially moulting creature be possible? such as a creature which grows without moulting, but also pupates to become an adult?