Simulating an Evolving Microcosmos | The Path to Multicellularity
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- เผยแพร่เมื่อ 9 มิ.ย. 2024
- In this video I showcase a program that I have been working on for simulating evolution by natural selection. I dive into various mechanisms of the simulation and go over some interesting real-life biology in the process. The key aim of this project is to evolve multicellular organisms, starting from single-celled protozoa-like creatures that must collect mass and energy from their surroundings in order to survive, grow and reproduce.
Chapters:
00:00 - Introduction
00:56 - Life of a protozoan
02:46 - The start of the simulation
05:57 - How the cells work
06:53 - Introducing multicellular colonies
08:33 - Understanding evolution
11:38 - Looking at data from the simulation
13:27 - Evolving epigenetics introduction
14:14 - Waddington's Landscape and cell specialisation
15:22 - The Central Dogma of Molecular Biology
16:05 - Gene Regulatory Networks
16:54 - Outro
17:30 - Watching the simulation
Find the project on GitHub:
github.com/DylanCope/Evolving...
Credits:
Tectonic plates animation: Scotese, C.R., 2016. Plate Tectonics, Paleogeography, and Ice Ages, (Modern World - 540Ma)
• Plate Tectonics, 540M...
Gene expression and cell specialisation diagram: Prof. Dave Explains, 2017. The origin of multicellular life
• The Origin of Multicel...
Stock footage of organisms under a microscope: • living under a microsc...
Music by Vincent Rubinetti
Download the music on Bandcamp:
vincerubinetti.bandcamp.com/a...
Stream the music on Spotify:
open.spotify.com/album/1dVyjw...
This video was made possible thanks to the fantastic mathematical animation software Manim Community, originally developed by @3blue1brown
www.manim.community/
Socials:
Twitter: / dylanrobertcope - วิทยาศาสตร์และเทคโนโลยี
One of the greatest problems I had with "evolution simulators" is that they are almost always limited to a few stats, perhaps a neural network, and left there. Only one other evolution simulator actually evolved body parts in a meaningful matter(The Life Engine), and even then not to the extent which you have. Well done.
Cheers! Your comment hits on one of the reasons I'm motivated to work on this project; to find ways for evolution to really surprise me. As you say, many simulations are essentially just optimising over some fixed stats, which really leaves very little room for surprise.
I would disagree just cuz i like the bibites
@@dylancope You are right, but I think this is why this type of project is scary to undertake. Because if you want to simulate life in a somewhat accurate way, you'll need to simulate genes, molecules, and to get to complex life you'll need billions and billions of these which would require super computers.
Also you are using neural networks do handle cells, but those cells are supposed to become neurons afterwards lol, but it would be very tedious to evolve cells without neurons.
Exactly!! I second this. This project is very promising! And I already love your videos
What is that “evolution simulator” called about evolving body parts in a meaningful matter? I’d like to look for any evolution simulators that can evolve not just their brain, but also body parts, stats, etc. Basically very similar to the real evolution.
I've had a very similar idea for the longest time as I'm absolutely fascinated by artificial life simulations. Kudos for actually executing it!
This is absolutely brilliant. As a fellow math/biol channel, I think this is one of the coolest youtube videos on evolution I’ve come across. Kudos!
Thank you! I just checked out your content and it's fascinating stuff - I'll be working my way through your back catalogue :)
The complex molecules thing is brilliant! As other sims have shown, predation is hard - but in our world the number of vitamins we would really prefer to get from other organisms is way more than is usually simulated (as in, not at all). A brilliant addition.
Cheers! It's a part of the sim I have been expanding so there will be update videos to come :)
When is the next one coming out?@@dylancope
this is brilliant. Closest thing to first-principles evolutionary sim I've seen thus far.
I could even see a point in your sim where it looked like your individual cells almost glued together into a stomach of sorts. They didn't hold out in that shape, but it was quite close.
Even more than Life Engine?
@@revimfadli4666 Oh Life Engine is also brilliant in its utter simplicity, but I think this one being grid-free is a really good thing that can't quite be compared with that one
PLEASE upload more; this looks amazing! best evolution sim ive seen yet
This video was top tier. Got really excited when you started mentioning allopatric speciation, I like this topic and seeing it in simulation is very nice) Keep up the good content
Allopatric speciation greatly helped against extinction in Life Engine
I'm so glad TH-cam showed me this. Please lean into your talent for making videos like this, and make more.
Loved it. Thanks! I do biotechnology and this is my favorite evolution simulator a have encountered (even at this very initial state) also I would love (I NEED) to see the evolution playout as you accompany the events. In this video you mostly explained how it works. Now I want to see it in action. Keep this amazing work!! The epigenetics will be a challenge
You just gained a new subscriber ❤️ (I literally don't know if this word exists but it's ok to invent word in English)
Thank you! :)
Yes! A 10-60 minutes recording of the simulation might work as easy "extra content" to boost the channel's algorithm stats
Projects and videos like these are what make me always come back to programming and learning about the relationship between chemistry and biology, thank you for making this :)
The music is so fitting too, I just stared at the screen like a hypnotized chicken the whole time
Found this vid a week ago and can not stop thinking about it. I don't often rewatch the same video but this one has me hooked on the presentation and concept of this cell evolution simulation.
Wow thank you!
I love biology + programming so much, but there's almost no videos on TH-cam I haven't watched yet with that theme, thank you for your work!
I've always wanted to create a life simulation, but I never knew how to start. I mean, I know how to code and program, but there are just too many factors in a simulation, and I wanted to create one entirely on my own.
Watching this helped me get a general idea of what things to focus on when starting my project. I will certainly try to work on it now.
the field is still new to theres lots of opportunity, and making your own approach will increase the chances of doing something innovative
Good luck w/ your project friend
Anything you make with any rules has a good chance of having some sort of pattern of varying levels of interest, just try applying any old set of rules and you'll likely end up with something even if it's not what you wanted.
We need part 2! Absolutely amazing project
It's in the works :) glad you liked it
@@dylancope if its still in the works then the finished product must be awesome
The movement restriction theory really gives me something to think about, it makes a lot of sense seeing as many both simple and complex animals grow inside of rocks and other structures, like for example the ''living rock''.
Please, don't stop your work, this is amazing
Thank you for the encouragement :)
You're definitely gonna be a "big" youtuber, or at least much bigger than what you are now. Like come on you have 400 subs and this video quality is just incredible. Great job!!!
Hope he could keep it up like Bibites etc
I agree. I mean, if at the time you posted this it was 400 subs, they grew 1,500 subs in five days.
Yeah, I'm getting major Primer vibes here.
almost 5k subs now, gg
8k
Similar to the life simulator “Bibites” but better in a lot of ways, amazing work!
Absolutely brilliant, can't wait for the continuation of this series! If you keep this quality up and start posting relatively frequently, you are sure to grow to become a large youtube channel in no time!
I've been wanting to find something like this for so long! and just now found it! I know you have thousands of potential fans waiting to see this, please keep making more videos! Your audience and subs will grow
This just popped up in my feed, and I'm really glad it did. I hope you'll make more videos on this simulation, and more videos in general.
This is brilliant work.. The animations are incredble..
Love this! Hope the next video is around the corner 👀
Halfway through the video, I thought about suggesting a way for cells of the same species to differentiate and specialize, but I can see you already thought of that! Nice simulation.
This is one of the best evolutionary simulation videos that I have ever seen and I am always anxiously waiting for the next one, I hope I can see it soon (:
This video was absolutely fascinating. Love the editing too :)
Found this when looking up the bibites because I was interested and maybe when I looked at this I’ve just become very interested in this subject of artificial life. Please keep up this project!
Loved it. I hope one day you find enough time and energy to continue with this content.
This video has reached a rather large audience for your channel, Congratulations! I found it very pleasing to watch and adding to the great network of TH-cam evolution simulator videos and channels. One thing though that I think you might benefit from is something Michael from Vsauce said recently, and I'm going to paraphrase here, " you shouldn't underestimate your audiences comprehension of a subject matter, but instead their knowledge of the vocabulary". If you take this into account I think you will be able to reach a wider audience for your upcoming videos on this subject by spending a touch more time explaining each step of more complicated ideas, especially in future chapters similar to this video's "Understanding evolution", and "Looking at data from the simulation". Your use of 3B1B's Manim is excellent in a quest to teach the masses and your graphs are very helpful, though, perhaps easing viewers into the graphs by explaining the concepts they are showing before the graph instead of during. That will give them less of a distraction and allow from them to grasp the concepts better before going into the actual data. Lastly, one section I think you should be carful of is during your explanation of Pooled Standard Deviation (10:33 -ish), taking a bit more time to explain what that exactly is, with simpler diction, for general audience members who are not as math savvy. Obviously that should apply to any future math concepts covered by this series going forward.
I hope these pointers aren't taken as an attack on your work and instead merely as constructive criticisms that I noticed during my viewing experience. I also hope that this series will continue and that your channel will grow to an even wider audience. I look forward to seeing that become a reality.
Thank you for the feedback! I will definitely consider what you've said here going forward - that Micheal Stevens quote is useful :)
@@dylancope Once again amazing video and im excited to see more on the multicellular concept as a lot of the evo-sim channels are doing mostly single cell stuff.
@@dylancope yeah, firstly thank you: superb content, excellent simulator.
Sadly, as English is non-native for me, even though I mostly watch more dense contents at .75 speed and even pause and ponder over new concepts, there were a few words/phrases I couldn't make out even after repeated view of the section (Not even with the help of automatic subtitles could I make sense of those). Minor stuff, but I can imagine that it may cause some discomfort for those not fluent in English....
@@dylancope Okey, I've re-evaluated my response:
I've figured out what was distractive for me: the way how you pronounce some words with "r" inside them....("curve" sounds like "code") and also the endings of some words were "cut off".
Once in every second, third sentence: nothing to worry about, at least I practiced some more real life English. Cheers
Definitely one of the better simulations ive seen. I appreciate youve largely resisted the urge to gamify this simulation, which most youtube simulations do. I feel the beauty of these simulations is laying out the rules, and watching the behavior naturally occur from them. Not constructing the rules to force the behavior.
Thanks! Yeah I'm definitely not making a game. The UI exists to watch and analyse the simulation. The only interaction that has been implemented was some stuff I added for debugging - you can move things around and kill cells.
The only plans I have for the UI involve a screen for setting up a new custom simulation, loading an existing one, and hopefully a dashboard to see the statistics over time.
I wonder which ones gamify the sim, and how?
Now THIS is a simulation game! The attention to detail is astounding! Great job.
rly looking forward to the rest of this, and playing around w it when i can. i've seen so many other life sims, but none of them are this in depth, and i can't wait to see what u do w it
This video is very well made, on top of a really intriguing simulation. I hope you stay with it, good luck
Keep it up! I am amazed at the group of people this video has collected. I’ve dreamt of doing a very similar project, regulatory networks and all! Kudos to you for getting started and making it look beautiful, with great narration to boot!
Thank you! :)
And I know the response to the video has been so much more than I expected!
This is one of the most fantastic videos I have seen on the subject. Most projects don't have any space for emergent behavior. For example in most projects, predation is hard coded and two types of species exist (apart from plants) but here the idea of manufacturing complex molecules is a very brilliant idea. Best of luck for future projects.
I have toyed around with removing the distinction between plants and protozoa entirely. They both inherit from the same base class and I could just make "chlorophyll" a complex molecule that forces you to be green and produces mass and energy idly.
However, one of the problems is the computational cost of the simulation. Currently, in order to run it I have to cap the types of cells individually - e.g. let there only be 5000 plants and 2000 protozoa.
The plants tend to reach this cap pretty fast and stay there. The problem is that when a population is up against this cap evolution essentially stops working very efficiently as attempts to split often end up with the children not being produced. They fail to be added to the environment because to do so would exceed the cap.
I have a couple ideas to get around this - I just implemented the idea of "local caps" that limits capacities to each region of the world. I could also debuff plants, but that might lead to more extinction events. Anyways there's lots to follow-up on!
@@dylancope local caps sound more realistic... I'm not a programmer, but couldn't it be coded that after the local cap is reached , newly spawned plants would be compared with other plants in the region according to some evolutionary trait and simply replace the least fitted, which would disappear (let's say this would imitate plants overgrown by others not getting enough sunlight).
Such trait could be the calorie/energy content which would be thus selected both positively and negatively by being a more preferred food of the protozoans...
Just thinking 🤔
@@dylancope I've been daydreaming about this kind of project for years, but never got around to coding one. So, take this with a grain of salt:
First: Is there a way to have a time varying, per-individual "metabolic rate" and/or probability of cell division? Could this be a function of something in the environment?
Second: You already have a system for pheromones -- what if you expanded that to include release + absorption of oxygen and/or CO2?
If you find a sufficiently-clever way to combine those two concepts, you could set up a system where overpopulation releases too much CO2 into the water, which slows down metabolic rate and with it reproductive rate.
Just a thought. LOVED the video!
@@dylancope It would be nice if it was a non-rigid cap where it's possible to go over the cap, but doing so results in worsened environmental conditions. For instance, divide a total amount of sun to all the plants meaning when there are more plants there is less sun per plant.
I LOVE how this guy pays attention to the details of the video and leaves links to them in the description unlike all of the other youtubers.
Very well done, and I love that you implemented your own UI. Thank you for posting this.
This video was visually and audibly pleasing, and mentally stimulating. More soon please, very interested to see how this develops
Still waiting for the updates...😥😥
Truly amazing ! Fantastic work dude - I wonder how long before some game companies start sniffing at your door !
Awesome video! Well explained and nice visuals! This video should get more attention!
Love this! What a great explanation of the topic, and I loved the animation of the whole video
Between this and the Bibites, the cellular automata genre has gotten incredibly interesting. Thank you so much for taking a detailed mathematical approach; its amazing!
Awesome stuff! Fantastic biological explanations, looking forward to future videos.
really cool vid, there's a lot to evolution that i would never have learned in education cause i just didn't study down this field... so getting to see a cool visualisation is reall neat. dipping our toes into many different fields to see what impact they have on your model. easy sub, great vid.
This was super neat! I love simulations on evolution and this one slaps.
Thanks not only for the simulation but the science around evolution
Hope you still plan on developing this further, so good!
This is absolutely amazing. More!!!
Incredible simulation! I hope to see more of it
Can't wait for the next video! Great stuff
You should add flagella that not only add motion but also create currents (just a collider with a force) and we can hopefully see the evolution of the sponge (the best animal)
This is so cool and well constructed, wish everyone appreciated the insane science
Please make more videos following this project!
Extremely fascinating, I'm sure it must have taken hundreds of hours to put this together.
The animations are really good. I can't even think how much time did you take to do it haha. I really like evolution simulators and it would be great if the subjects could generate different traits from zero based on their environment. And when I said "from zero", I mean without any prescribed code behing
I’ve also thought about this, but from what I know, it would be very complicated to actually make
@@realbrickbread Perhaps a pool of features could be created that appear randomly in the following generations and that these features can mutate in size or shape also randomly in the following generations if natural selection allows them to persist in the environment. For example, a vestige of a limb appears that will later grow or change its shape.
This is the most exciting thing I seen on TH-cam recommended
This is absolutely incredible!
A very interresting simulation, and well documented, well done
Thank you!
delightfull simmulation and well made video
One of the coolest looking multi-cell implementations I've seen!
Cheers! :)
I've always wanted to do an experiment like this. I'm glad someone is.
This project is incredible and even reminds me of a simulator called "cell lab" but perfected with proper cell adhesion and if i could i would suggest making certain cells be able to sacrifice self viability aka specialisation for a specific role such as fast movement , defence or even increased central control almost like a brain the potential is incredible and i would love to see something like that in the future and the potential for evolutionary surprises would be incredible! i also applaud you for the project and thank you for all your effort!
Man, the cell lab community is so amazing, its impressive what people can do with these kinds of games
Cell lab simulate the morphology evolution and very simple embryogenesis very well, but a bit lacking and limited in the genetic encoding and the limited "landscape" a dish can provide.
And I've done experiments using android simulator to run for hundreds of thousands of hours purely on random mutation. The result is less impressive without "human design" creatures. Although they did evolve multicellular linking with plant like "blankets", but few mobile cell lineages (although some evolved very surprising ways of movements by "farting" small child to push them toward different directions, it seems to be a better way of control its hunting range, than Flagellocyte which could waste energy and hard to "stop").
And the PC version is still being working on I believe.
@@countingtls from my experimentation some interesting forms did emerge like ones you mentioned such as farting predators however im surprised you didnt mention swimmer evolution as those seem to be pretty common , tho i will admit your right , no matter what method ive used true complex creatures never emerge due to how low the chance is and that even the transitional forms wouldn't survive long enough to give form to a future form. That is one of the many problems with evolving in cell lab tho evolving human made creatures do allow for more interesting results
@@obiomajronyekwere4469 The emergence of the simple swimmer rely heavily on the starting condition, where nutrient particles are provided with sufficient quantity and distribution, but not too much where the splitting force is enough to survive.
In my experiments, I want to see if hierarchical species can evolve purely from light to photosynthesis and then "herbivores" and different levels of predators. Once there are enough plants, the chance of evolving swimmers will be reduced quite a lot and the farting movement creatures seem to dominate the mobility methods.
Maybe there are certain density and other factors combined can make their coexistence more likely, but in general for swimmers to evolve, the conditions of the dishes have to change depends on the current evolution stage to make them emerge, which will be interventions at the time I didn't wish to impose.
@@countingtls That is very interesting and you are right on the swimmers somewhat it does rely heavily on starting conditions making single cells viable but slowly allowing random chance to produce swimmers.
However i doubt the ecosystem you are attempting to make is viable , with my experimentations such ecosystems almost always crash due to devouros aka predation and a light centered ecosystem always seems to be unstable
That was a class video. I'm a science student myself so it was right up my street. I love evolutionary biology and have always found it fascinating. Great job 👌
I love these types of videos! keep it up :D
Wow, not only is this video interesting. It is also well put together
I love seein this kind of research! Explaination about how genenetics and evolutions through math visualisation is just awesomness in my brain :D
I have always wanted to see a decent evolution simulator. I'm old enough to remember what a huge let-down Spore was at release. Always seemed like there was potential for a great simulator, but it never got mined -- until now! This is an incredible bit of engineering -- really well done! I will download and play with it when I get a chance
It’s kind of annoying no game like spore has come out recently, only games that explore one aspect have (single celled, civilization, resources, and space colonization), no game has truly explored the level of player controlled evolution and survival since then, that’s why I still play it sometimes. It’s disappointing, but the only option for its experience.
I love The Bibites and also what Primer does. I've added you to that list now. Subbed. Can't wait to see where this all goes!
I love this video! Thanks for making it
extremly clever and well done!
good job, subscribed to see further implementation 👍
This is cool, thanks for sharing the code. It's interesting that you use Java Swing to do the graphics - back 10 or so years ago I made a simulator for electric charges that used Java Swing to do real time graphics and I would have expected that to be slow but it worked pretty well at a decent FPS. Have you looked into using GPU acceleration for the simulation? I would guess if that could be done it would speed things up a huge amount.
Hey - since releasing this video I've been working on a 2.0 of the project and have ported it over to libgdx and box2d. Performance is better so far with most of the intense features re-added. I've offloaded more of the rendering to pre-rendered sprites and shaders.
I've also been learning some JCuda programming and that has accelerated the background chemical field massively!
@@dylancope highly recommend against java for this sort of thing, its meant for business-applications, its quite bad at succinctly expressing mathematical models
Absolutely amazing.
Glad to say I was here when you had less than 2k subs. Very interesting work!
It is nice to see good quality video on biology, will you continue adding new similar quality videos?
Yep I have several more video projects in the works that I'm excited about :)
awesome! it's been a while since i saw a new life simulation. and you have put in so many cool aspects! gene regularion, cell chemisty, multicellularity, oh my! i am very excited where this will go.
holy shit i wish i could give a video multiple like this is the coolest thing i've ever seen
That's really nice of you to say! I'm glad you found it interesting 😀
Amazing video. Very interesting topic and very cool to see the statistical side of genetics.
this is awesome simulation
A bit of correction/addition on development and pluripotency of initial cells: there are, in fact, a minimum of three approaches in Nature: one of them is similiar to what you've described - starting cells are totipotent and can potentially differentiate into any other cell, heavily depending on external (to exact cell, but maybe not to organism as a whole) factors. After final differentiation there is no redifferentiation possible (although some near-end stem cells would stay in such near-end stem condition for tissue to be able to reproduce), but if you kill/delete some cells from early embryo it will still develop as usual (some animals can even assemble scattered cells into new embryo if it is an very early stage - some sea urchins would be an example). Another example would be us, vertebrates.
The second approach is way more rigid, hovewer - even zygote has anisotropic distribution of specific chemicals in it and even after the first division first two daughter cells are bound to their fates - one will inevitably grow/develop into anterior part of an organism and the other will inevitably grow/develop into posterior. All the other divisions only make this fate more precise for new daughter cells. If you remove cells from developing embryo of such type your end-point organism would lack some bodyparts/organs/tissues, for example, removal of any of the first two daughter cells would result in development of only a half of an organism - anterior or posterior depending on which one you remove. A good example of such taxa is Spiralia (mostly known for molluscs and annelids). Another good example is nematodes - some of them even delete some genes from some cells as they differentiate - so they not just stop expressing this genes, they physically lack them.
Both of this systems have division into germ and somatic cell lines in early development. Germ cells would become functional part of sexual organs (but not necessarily their structural parts, i.e. genitalia - these are often made from somatic ones) and will produce gametes and ultimately zygotes which are totipotent again. Somatic cells will become the whole other parts of an organism, something like a space suit or space ship for germ cells if you want an analogy.
The third system lacks such dramatic cell line division and/or end-point differentiation and "somatic" cells can become germline or just totipotent under some conditions. A good example would be hydra polyp that form gametes (that will eventually form hibernating zygotes) in autumn and buds that will develop into small polyps (the main mode of hydra reproduction) in summer both from just normal somatic cells - they lack any specific germ cells. Another good example would be plants - that's why you can reproduce many of the plant species by dividing and replanting adult organism (ofcourse there might be some constraints in technical details of this process).
This three-type classification is also a bit simplifying, but it catches the main ideas of developmental biology of multicellular organisms and especially animals. Hope you'll find it useful.
And about your simulation - the incorporation of complex organic molecules as required/signalling components is great and awesome, never saw anything like this in any other evolution simulator.
Thank you for all this great information! I have been doing quite a bit of reading on differentiation but have not yet settled on how I'm going to implement differential pluripotency, so your comment is really valuable! My current idea is to implement a basic form of cytoplasmic determinants that are distributed to children upon cytokinesis. Cells will be able to produce determinants or destroy determinants already present.
Gene regulatory networks will then be able to take determinants as inputs, thus allowing parents to attempt to condition the expression of genes in the next generation.
I really like the video - a lot of thought and consideration has gone into an interesting design for this evolution sim :) I would however like to point out that the full-commitment interpretation of Waddington's landscape shown in the video is no longer the putative model of cell differentiation. This one-way street concept was disproven by the work of Nobel Laureate Shinya Yamanaka on the creation of induced pluripotent stem cells - showing that differentiation may be reversed in some cases!
Thank you for your comment, and bringing up the nuances regarding Waddington's Landscape! I purposefully left out complications such as Yamanaka factors as I thought the video was already quite heavy, although they are a completely fascinating aspect of modern epigenetics. Maybe at some point in the future I may address it :)
this is stellar work. Most of my interest in evolutionary systems (and biology in general) is how certains system will be favorised, why and how, and what's the result that come out of it. I hope to see this project turn into a professional project being worked on full time, paving the way for simulations trying to try to recreating environnements closer to reality instead of basing themselves on variables for what would happen in a real environnement (the more realistics simulations more difficult due to requiring way more precise knowledge). And the creation of a third dimension as well. Would be interesting to see what comes out of it.
WOW! that was my reaction, as a bio student/ evolution lover .Great job, I am looking forward to the next video.
absolutely awsome!
MAD underrated!
Oooh! Epigenetics and gene-to-gene interaction/recursion have been something I've always wanted to see in one of these (and something I've played with in the plans for my own evolution simulator that I'll probably never get around to coding). Excited to see further updates!
Amazing. Subscribed.
This Is genuis the coding Is just perfect the naration
This is really fascinating to me as someone who is doing a Masters in Biotech.
Well, I'm fascinated to see where this goes.
Very interested in seeing how this goes. Edit: specially if later we see some emergent morphogenesis.
Hey really great work you’re doing here. Thank you for sharing
Thank you!
Great vid, would love to see more. May be wrong, may need to see more but it seems like the epigenetics and genetics systems here are functionally equivalant.
Great video to play in the background while doing something else!
Lol idk if this is a compliment, but tbh I watch most videos like this so I get it
It's so rare to see physical barriers in a sim like this, I love it!
Always love me a good evolution simulation. Glad to see a working "into carnivorous" solution via simplifying the collection of nutrients instead of making it themselves. So many of these fall into "It's just better to eat the grass" due to basic energy systems.
this is amazing
so great!!!!
Excellent explanation
Thank you!