Some of the first items on our Multicellular Stage Roadmap are “Spore reproduction mode as extension for budding” (1.2) and “Sexual reproduction” (1.4), but we don’t have a fully resolved design yet, so I hope we can do that here. I’ve elsewhere already tried to summarise the relevant theory.
Design objectives:
- Provide an editor choice that significantly change the gameplay experience in the stage, setting it apart more from the Microbe Stage as well. Each option that is available should feel significantly different to play.
- As much as is possible within the game context, try to represent what we know of the real life evolution of sexual reproduction and different reproduction modes.
- I expect we will want the default situation in Macroscopic to be that juveniles are relatively fully-formed organisms that are either mini versions of adults or fully formed larvae (if we’re doing multiple life stages). It would thematically work well if the system that allows that (“eggs”) is already an option present at the end of the Multicellular Stage.
- Do all of this within as little programming time as possible, so that we can finish the Multicellular stage within the year and still fit in all the other features on the roadmap.
My conclusions from the theory:
- “Spore” is a relatively vague term, but especially when we look at the more well-known uses (fungi, plants, algae) are relatively small dispersion systems that are good at spreading, but don’t carry a lot of resources. We could easily keep the current default reproduction method and call it a spore. The only thing missing is the cell being specifically designed for this purpose and disappearing afterwards.
- Budding growth, on the other hand, can be one cell, but can also mean much larger and more complete offspring budding off.
- A very significant trend in real life evolution was the transition from identical gametes to binary gametes (the typical egg-and-sperm situation) it would be great to represent this somehow. (isogamy → anisogamy)
- Both for budding growth and the egg in anisogamy, there is pretty much a smooth sliding scale from “very minimal resources, lots of offspring” to “large resource investment, few offspring”. We can include this in several ways: as a binary choice, through a slider, or through cell editor design of the “egg”.
- In real life, sexual reproduction is a general eukaryote thing, but the problem is that this would make it a Microbe Stage feature… So I suggest we justify the Multicellular Stage transition to sexual reproduction as when it becomes the “primary” mode of reproduction.
Things to in my opinion avoid from the theory:
Cut theory
- Simultaneously having multiple reproductive modes: While extremely common in life in this category (especially for example having one sexual and at least one asexual mode), this is unnecessary complication. It would be difficult to select which to use, and if we grant some bonus to the player for bothering to use the more complicated sexual reproduction, it does not make sense to still give that bonus when the player is not using sexual reproduction.
Instead, we will just show species only using one reproduction method. If necessary, we can use the justification that if in use, sexual reproduction is more important in creating changes in the species, or “we just show the most important of the modes used by this species”. - Fragmentation: With budding or egg-style reproduction we can balance how large/mature the offspring is by increasing the reproduction cost that the previous generation must spend. But with fragmentation, you could start with for example a half-mature organism, without the previous generation having to collect that as “extra” compounds. It’s just splitting after all. So we can’t implement “fragmentation” as convincingly different from “budding” without making it an unbalanced choice in the context of a game.
- dormancy: one thing that does sometimes make people call something a “spore” is that it is resistant to adverse conditions and can stay dormant for a long time before germinating. But I don’t think we have the mechanical base in the Thrive Multicellular Stage to properly represent this (what would the gameplay difference between a dormant and non-dormant “egg” be?). So we also can’t use this as the deciding factor for what makes a “spore”.
Sexual Reproduction bonus
Unless the specific reproduction modes (see next section) associated with sexual reproduction somehow have immediate benefits over those related to asexual reproduction, the increased effort for sexual reproduction needs to have some bonuses attached to it. Because of how auto-evo (and real life evolution) works, this can’t just be an editor benefit, it has to be itself beneficial to gameplay from the moment you evolve it.
I would propose:
- A significant but not extreme MP discount, like 20-30%.
- A significant positive multiplier to environmental tolerances (the width of the bracket, where applicable.
- And a third thing to represent “generally improved performance”, but ideally I don’t want to hit the exact same modifier as cells specialization does. (though that would be easier…)
Design for specific reproduction modes
With the theory and design goals in mind, there are a number of ways this could be implemented. I am not entirely sure what the imagined “scope” of these features was, so I offer three different designs as examples. There are also intermediate options here, they are just indicatory for what the bounds are.
Several of these involve the player starting off with more than one cell after respawning, and I would suggest balancing that by increasing the reproduction cost that needs to be collected before reproducing. So that has the nett effect of making you spend more time as the fully mature organism, instead of a small amount of cells. I think this also handily mimics evolutionary history.
The simpler implementation
- Budding: Works as currently, but there is an added slider that lets you determine how large the “bud” is. (so how much cells you start with.
- Sexual: Instead of going immediately to the editor, you release eggs or sperm (both with fixed models) that need to meet before you go to the editor. There is again a slider that lets yo determine the size of the egg, and with that the number of cells you start with.
The most “scientifically accurate” implementation
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Sexual reproduction: A Microbe Stage Feature. It would be either automatically activated by placing a nucleus, or be an upgrade to the nucleus (actually, having it as a separate option elsewhere might be easier to translate to the next stage).Instead of going to the editor immediately when pressing the button, the cell would split into two gametes, and you need to find another gamete to collide with before going to the editor (from that point, things would progress as currently). The gametes would be of two types that look just like your normal cell, and you can’t edit them separately. But, you do need to collide with a cell of the other type (I would suggest colour-coding the nuclei).
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Isogamy (sexual): The Multicellular Stage would start off with you still having this same basic system, now releasing a number of identical gametes. But since they are a separate cell type, you can immediately edit what they look like as any other cell.
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Anisogamy (egg): You can then use the reproduction tab to switch to anisogamy, which splits your gametes into two different cell types that you can design separately. This needs more detailed design to have incentives towards the eggs and sperm situation we often see. Instead of just starting with one cell, offspring start with a number of cells depending on how large the zygote is.
Assuming staying asexual is an option:
- Budding: Being asexual and going to the Multicellular starts you off budding single cells, as now. (optionally, this could have a slider letting you make bigger buds).
- “Spore”: You can switch to this from the reproduction tab, it allows you to design a “spore” cell like how you design gametes in sexual reproduction. The next generation starts you in control of a spore cell, but on command, you can grow into a number of cells based on the size of the spore. (this same behaviour can be applied to the “egg” mode, but it’s not necessary there.
The “balanced” implementation
- Budding: Being asexual and going to the Multicellular starts you off budding single cells, as now. (optionally, this could have a slider letting you make bigger buds).
- “Spore”: You can switch to this from the reproduction tab, it allows you to design a “spore” cell. The next generation starts you in control of a spore cell, but on command, you can grow into a number of cells based on the size of the spore. (this same behaviour can be applied to the “egg” mode, but it’s not necessary there.
- Isogamy (sexual): You switch to releasing a number of identical gametes that need to collide with other gametes. Since they are a separate cell type, you can edit what they look like as any other cell.
- Anisogamy (egg): You can then use the reproduction tab to switch to anisogamy, which splits your gametes into two different cell types that you can design separately. This needs more detailed design to have incentives towards the eggs and sperm situation we often see. Instead of just starting with one cell, offspring start with a number of cells depending on how large the “egg” is.
Remaining thoughts
- I am sure there will be comments from our more professional programmer(s) on this, but some of these have what I believe are significant technical challenges. For example, a player-controlled spore cell that then needs to transform into a different type, or have the player’s control transfer to a different cell. So I hope to hear which things are more and less feasible.
- I intentionally did not put much requirements on the presentation above, but it would be nice if for example with the “egg”-type reproduction mode you can see your organism grow within an “egg shell” before it dissolves.
- Similarly, a “bud” of more than one cell could be shown actually “growing on” an adult, but that seems like a big hassle to implement.
- As mentioned before, the word “spore” is used for a lot of things, so here I’ve pretty much treated it as any “specialised dispersal cell for asexual reproduction”, which covers most cases. Especially what people will be most familiar with from fungi and plants.