Every lifeform provides support per turn via the prestige mechanic. The simple way to understand this is to take the prestige number of the lifeform and know that the first animal of that type is worth that much support per turn. We'll deal with the actual calculations when we get to prestige optimization.

Some animals are really pretty, and provide additional support/turn bonuses if they're in the same climate zone as a city. Lions and polar bears are kinda scary, and provide support/turn penalties if they're in the same climate zone as a city.

Almost all plants provide oxygen and atmosphere; this means that once you have the prerequisites in place, you can accelerate your terraforming with plants. Note that the cactus does not provide terraforming benefits, and the palm tree provides double the usual terraforming benefits.

Every species of bacteria provides some specific benefit in addition to prestige. Methanogenium generates heat. Metallidurians generate titantium. Cyanophyta is effectively a microscopic plant species that doesn't need water. Dark Bacteria turns everything black, resulting in a local increase in heat. Artificial Bacteria produces science points. And there are some others that I never pick.

Every spreader can spread any species of that type that you've unlocked. So you don't have to build separate spreaders for lions vs deer vs rabbits vs penguins. You just build an animal spreader and then target a different region for a different species whenever the cooldown runs out.

So, if massive support per turn bonuses are not enough for you, then maybe you'd like some titanium with that?

The thing that brings game over in Terraformers is expectation growth. You get to turn 60, and all of a sudden your colonists smack you with an expectations penalty of 70 points per turn. Imagine if you had built one bacteria spreader on turn 20, and you didn't have to find 70 points per turn in extra income, you only had to find 10 points per turn. Because that's exactly how it works.

Need to be convinced? Here's some maths.
Let's say you build a CO2 factory in one of your cities, and it produces 1 heat/turn and 1 atmosphere/turn.

To increase the temperature of the planet one step, you need to generate 30 heat. To improve the atmosphere one step, you need to generate 60 atmosphere. You're going to see this:

Turn 1: build CO2 factory
Turn 31: Get rewarded for heat level 1 (100 support payment +1 Quality of life planetwide)
Turn 61: Get rewarded for atmosphere level 1 (100 support payment +1 Quality of life planetwide)
Turn 91: Get rewarded for heat level 2 (200 support payment +1 Quality of life planetwide)
The next reward is on turn 181.

So, over the course of 91 turns, we can say that a CO2 factory is worth 400 support, plus 3 quality of life planetwide. Assuming a human population of 20 colonists, 3 quality of life planetwide is worth 20*3 = 60 support/turn.

Let's say that you get yourself one lifeform spreader, and you load Methanogenium in it. You've found a location that is warm enough for Methanogenium (a large portion of the planet will support it) and you build a bacteria spreader there. You'll see something like this:

Turn 1: Build bacteria spreader. Spread methanogenium. Get rewarded for first spread of Methanogenium. (10 support payment + 1 support/turn)
Turn 12: Bacteria spreader is ready to go again. Spread methanogenium again. No reward.
Turn 22: Get rewarded for heat level 1 (100 support payment +1 Quality of life planetwide)
Turn 23: Bacteria spreader is ready to go again. Spread methanogenium again. Get rewarded for third spread of Methanogenium (10 support payment + 1 support/turn)
Turn 34: Bacteria spreader is ready to go again. Spread methanogenium again. No reward.
Turn 40: Get rewarded for heat level 2 (200 support payment +1 Quality of life planetwide)
Turn 45: Bacteria spreader is ready to go again. Spread methanogenium again. No reward.
Turn 56: Bacteria spreader is ready to go again. Spread methanogenium again. Get rewarded for sixth spread of Methanogenium (10 support payment +1 support/turn)
Turn 59: Get rewarded for heat level 3 (300 support payment +1 Quality of life planetwide)

So we can see that it takes 30% less time for the bacteria spreader to get us to the same quality of life improvement as we get from the first 90 turns of owning a CO2 spreader. During that time, the lifeform spreader has generated 630 support in fixed payments, and the total of support/turn payments for methanogenium spreading over that time is a 86.

Would you like 3 quality of life levels in 91 turns, with 400 worth of support bonuses on the side, or would you like to have them in 59 turns, with 714 worth of support bonuses on the side?

There are limits to the power and accuracy of this illustration. You might not be able to spread your methanogenium quite so quickly if the distance penalties and adjacency bonuses don't cancel each other out, or if your first spread goes to a location that's different to where the spreader is. And you're probably not actually going to build only one C02 spreader. But you're probably not going to actually build only one bacteria spreader either. And you might be able to get your second spreader to take advantage of adjacency bonuses from the first spreader, and go faster than that. If you use a mix of bacteria, you'll get slower terraforming and better lifeform spreading rewards. Then there's leader abilities... I think it would be fair to say that you could do 10-20% better than these calculations with perfect play, and up to 20-30% worse with bad luck or serious mistakes.

30% worse than 714 competes pretty well with 400.

But let's say you're not doing Path to a Red Planet, Blue Path or Green Path. If terraforming is not part of your objective, is it still worthwhile? The question becomes "How far are you from winning?"

If you're less than 22 turns from victory, then methanogenium is a bad investment. 21 turns after building your bacteria spreader (assuming it's your only terraforming asset), you'll be at 29/30 on the terrforming dial, and you won't have any quality of life improvements yet or major bonuses yet. With the one prestige bump right at the beginning, it will be as if you'd built a building that generates 1.5 support/turn (1.47619/turn at the absolute low point, assuming good spreader placement.)

As soon as you get that first terraforming level, everything changes. Now, your lifeforms investment is worth at least 4 + [the human popuation of Mars] per turn. So, assuming a fairly low human population of 8, your lifeform investment is worth 12 support/turn after 22 turns. If you have 22 turns before you win, one lifeform building is at least as good as having a hospital or entertainment center.

After you get the second terraforming level, you're undeniably ahead. Your investment is worth 7 + [2 * the human population of Mars] per turn. Assuming some population growth by then, let's say your human population is 15. If you are 40 turns or more from victory, one bacteria spreader will be worth 37 support/turn by the time you win. If you're 60 turns or more from victory, one bacteria spreader will be worth at least 60 support/turn because we're going to assume a human population of 20, and 3*20 is 60. In reality, your return will be more than the quality of life bonus, but it's really hard to justify and explain a good analysis of 'how much more'. If you ignore the non-quality-of-life benefits (that could be as high as 12 support/turn over the life of the investment, if you time it perfectly) you still get a really good number.

Think of your first bacteria spreader as a building that will be worth 60/support turn after a delay. Think of your second bacteria spreader as a building that accelerates the process of unlocking the benefits of the first spreader.

Cyanophyta
That's methanogenium. Cyanophyta produces +1 oxygen and +1 atmosphere, not just +1 heat. If you plug it into the same mathematical model, then you get your first terraforming level (oxygen) 2 turns quicker. At 30 turns, you get an atmosphere level to go with your oxygen level and your investment is worth the same as 40 turns of methanogenium. At 60 turns, it's worth 20 support/turn plus 5 times the human population of Mars. It finally peaks at 77 turns, at 20 support/turn plus 6 times the human population of Mars.

So why not do the cost/benefit analysis using cyanophyta? Because it's a picky lifeform, and it needs a heat level of zero or higher to survive. Which means you're not going to get the same sort of spread from it as you could with methanogenium. And yes, you can (and should) build heat with methanogenium and then blend it or switch it with cyanophyta. But I'm trying to a mathematical model that is simple, justifiable, and which produces results that people will recognize when they try to put it into practice.

And yes, there's the bacteria that produces +2 atmosphere/turn that produces results that are really similar to methanogenium, and it's easier to place too. But I can't remember what it's called, because atmosphere is not as good an investment as heat. (More on that later.)

Plants and animals
The returns are better with plants and animals, once you meet the prerequisites. The problem is that to truly justify them, you have to justify the prerequisites, and this analysis is complex enough as is. The good news is we just justified heat, which is the most common prerequisite.

If you're on the Red Path or doing the Ad Astra scenario, then terraforming doesn't contribute to your victory conditions. Therefore, the only reason to invest in lifeforms is for the support benefits. Given that lifeforms generate huge support benefits, you should make some investment, but you probably don't want to put huge amounts of thought or energy into lifeforms in these scenarios.

So:

Don't hire biologists Picking up a biologist leader is too much of an investment when it contributes nothing towards your victory condition. If you get offered a choice between two biologists, then have a look at the leader section and pick the one that is listed earlier than the other.

Don't think about lifeforms until the game offers you one. You probably won't be quite ready to do anything with them at that point anyway.

Your first pick should be a terraforming bacteria. Metallidurians are cool, and +1 titanium is nice, but it's unlikely that getting +1 titanium around turn 12 is going to be a major strategic difference. And it's even less likely that you're going to have a climate zone where metallidurians can survive that also has one of your cities in it. Look for a terraforming bacteria (that gives heat, oxygen and/or atmosphere) that you can place in zones that you can already see. Having a terraforming level done before turn 40 is going to make your support situation much easier to manage, so you're looking for something that can start work straight away.

Build one bacteria spreader as soon as you can afford it. The difference between 'zero lifeforms' and 'some lifeforms' is absolutely huge. You might never build another spreader of any sort ever. But don't delay with the first one.

Be skeptical of plants. Plants need rainfall. To get rainfall, you need oceans. To get oceans, you have to flood valuable real estate with water. Water imports can be a good source of victory points in Ad Astra, but you'll probably prioritize other projects through the early game. What you'll be doing with plants is looking for the ones that can survive on your dry and dusty world: pick low rainfall plants if you absolutely have to choose a plant.

Pick easy animals. Was your first bacteria one that makes oxygen? Then look for penguins, that can survive in any temperature. Did you start with heat? Then don't be too nervous about heat levels, focus on animals that don't need much oxygen.

Balance biodiversity against your other objectives. Having one copy of a lifeform somewhere on the planet generates prestige (and therefore support) much more efficiently than having many copies of the same lifeform. So before you replace ALL your bacteria with metallidurians, remember that it only produces titanium if it's in the same zone as a city. So maybe leave the rural bacteria alone if they're already in place and generating support benefits.

Consider having a 'mainly robots' climate zone. There's a bacterium that makes tritium, at the cost of also generating radiation. People don't like it much, but if you need tritium production, you might want to spread that bacteria in a couple of zones. If you have a zone where you only have one city, and the population of that city is mainly robots, then you'll have an easier time making use of that bacteria. (Once you've thought about it and decided that it's too much hassle, remember not to pick the bacteria that makes tritium. Or maybe pick the tritium bacteria and then make a special zone for it to live in, once you know it will be worth it.)

Lifeforms are very powerful terraforming tools. If your victory condition requires you to terraform the planet (Blue Path) or rewards you for terraforming the planet (Path to a Red Planet), then you should take lifeforms seriously as a tool for winning the scenario. (If you get offered the right leaders, then Path to a Red Planet can be completed quickly and successfully using a Green Path strategy as well.)

If you're focused on terraforming:

Plan to build spreaders. Bacteria spreaders need science, and they come out first. Plant spreaders need nitrates, and they come out second. Animal spreaders need oxygen, and they come out third. (But might get built before you do plants, if you're late with oceans.) They are external buildings, so you need an empty space on the world map. You'll want to spread them out if you can. You'll want multiple bacteria and plant spreaders.

Don't worry too much about animals. You can win without any animals at all, so when you have to choose between priorities, focus on the ones that generate terraforming.

Spread close to the spreader when you can. The cooldown before you can use the spreader again increases with distance from the spreader.

Plan to fill oceans. Plants that require rainfall are the most sustainable way of getting oxygen and atmosphere. Oceans also contribute directly to your victory condition. Get the first level of oceans as soon as you can do it without losing any claimed territory (don't forget that you can build dikes to protect claimed locations and cities). Try not to delay the second level of oceans, many parts of the planet will still be on zero rainfall at level 1 oceans.

Focus on life in the early game, supplement with buildings in the late game. The wonderful thing about spreaders is that they can be used again after a cooldown. So building them in the early game is especially valuable. As you get closer to endgame, the more strategic it is to use buildings for an extra push, rather than insisting on doing everything with bacteria and plants.

Heat and oceans first, oxygen and atmosphere second. Plants are a great way to make oxygen and atmosphere. Plants need heat and water to survive. So focus on heat and oceans first, so they can help you with oxygen and atmosphere.

Hire early-game biologists. Misha Kiyama can decrease the cooldown caused by one lifeform by 15%, and she can help you unlock the species with the most benefit. Hire her, get her to find methanogenium, and get her to make it 15% faster. That's a 15% increase in your heat terraforming rate that you get to keep for the rest of the game. It's also a quicker switchover from heat bacteria to oxygen/atmosphere bacteria. Isabella Torres can reduce the rainfall requirements for plants, making it easier to get palm trees (that produce 2 oxygen and atmosphere instead of 1) into play, and her passive increases oxygen production from factories as well as plants.

Consider atmosphere-only terraforming tools. Plants produce one unit of oxygen and one unit of atmosphere per turn. Atmosphere needs twice as many points to advance as oxygen does. If you're optimizing your Blue Path run and you want to finish all the dials at the same time, you'll want to supplement your plants with something that produces atmosphere only. (Either the bacteria whose name I can't remember, or relevant factories.) Alternatively, just push plants really really hard so that they carry atmosphere up quickly, and accept that oxygen will finish several turns earlier.

Green path victory is based on the total prestige of all your lifeforms. The Green Path strategy is very similar to the Blue Path strategy, but there are some differences.


Plan to build a lot of spreaders. Bacteria spreaders need science, and they come out first. Plant spreaders need nitrates, and they come out second. Animal spreaders need oxygen, and they come out third. (But might get built before you do plants, if you're late with oceans.) They are external buildings, so you need an empty space on the world map. You'll need to spread them out for efficient performance. You'll want multiple bacteria, plant and animal spreaders.

Prioritize exploration. You can't spread a species to a region unless you have explored one of the nodes in that region. You also don't get the climate data unless you've explored one of the nodes in that region. Somewhere on your planet there is a perfect deer habitat, and you're going to need to put deer there to maximize your prestige. Having a spreader sit idle because you haven't unlocked a region where you can spread something is a serious risk in the Green Path endgame.

Spread close to the spreader when you can. The cooldown before you can use the spreader again increases with distance from the spreader.

Plan to fill oceans. Plants that require rainfall are the most sustainable way of getting oxygen and atmosphere. Oceans also contribute directly to your victory condition. Get the first level of oceans as soon as you can do it without losing any claimed territory (don't forget that you can build dikes to protect claimed locations and cities). Try not to delay the second level of oceans, many parts of the planet will still be on zero rainfall at level 1 oceans.

Don't build terraforming buildings You won't need them, your lifeforms will get the job done. Use those resources on something you actually need.

Heat and oceans first, oxygen and atmosphere second. Plants are a great way to make oxygen and atmosphere. Plants need heat and water to survive. So focus on heat and oceans first, so they can help you with oxygen and atmosphere.

Hire biologists. All of them. Spam their 'import lifeform' ability until there are no lifeforms left for them to offer you. Make sure you use all of their genetic modification uses.

The endgame requires biodiversity The higher the difficulty, the more biodiversity you're going to need to get to the prestige target. Which means you're going to need a big library of species that are adapted to different climates, and you're going to need to deploy as many different species as you can.

Ignore the atmosphere dial. Your plants will push it up anyway, and none of the animals will care.

Understand the prestige mechanics. Which generates more prestige? Two regions that have Birds of Paradise in them, or one Birds of Paradise and one Penguins? What if it was six regions? What about four regions with Birds of Paradise and two regions of lions?
At lower difficulties, you can complete Green Path without going into the maths: it's enough to understand that more species is normally better than more of the same thing, and that you should look at the different prestige numbers and pick the big ones. If you avoid overwriting species and go for high-value species, you'll be OK.
At higher difficulties, you can populate the entire planet without winning. Which means that it really helps if you're aware of the fact that the second copy of a species gives you no benefit: you have to get to three to get a benefit from an additional copy of a species. You're also going to need to do the maths about whether to go with mutiple copies of a high-value species versus a greater variety of species. (And to work out if you actually have enough regions where the high-value species will actually survive...)

Spreaders are the things that make the lifeforms go. They're built in External building slots, which means that they need a little bit more planning than most buildings, especially since the ideal is to have a number of spreaders that are distributed across the planet. It's all about the cooldowns: you want your spreaders to fire as often as possible.

Every time a spreader spreads a lifeform, it has to wait before it can do it again. The cooldown is determined by the following things:

• Which lifeform you are spreading (sets the base cost)
  
• How many climate zones away from the spreader you are putting the lifeform (+25% per zone)
  
• Whether the lifeform exists in an adjacent climate zone (-20% if any adjacent copies - does not stack)
  
• Whether you are replacing an existing lifeform (-50% discount if so)

So, ideally, when placing a lifeform spreader, you're putting it in the middle of several climate zones where you can put something, and you're putting it inside a climate zone where you can put something straight away.

When you're placing multiple spreaders, you're avoiding putting them in a place where you already have a spreader or lifeform of the same type as the spreader.

When you're spreading lifeforms, you're not really worrying about whether you might want to put something else in that place in the late game: it can be really effective to replace one lifeform with another later on as the climate changes. (It's very rarely actually cheaper to do it this way, but it might not be much more expensive.)

Methanogenium is the absolute 'must pick first' lifeform. It's reasonably cold-tolerant, and it increases the temperature. Given that almost every other lifeform has a minimum heat requirement, I will build the planet up to 10 methanogenium zones as fast and hard as I can, so that the temperature dial maxes out quickly. This allows me to place the maximum variety of other species, means that I'm always getting an adjacency bonus when placing methanogenium, and then once the temperature gauge is full, I can replace it with other more prestigious bacteria.

Once I have a temperature level achieved, it's warm enough to replace some of my methanogenium with Cyanophyta. This gets me started on oxygen production. Alternatively, if I have a zone that starts on zero rainfall (as opposed to negative rainfall), then I will rush Oceans 1, and put in a Tundra Forest, which is the only plant that doesn't have a heat requirement.

For end-game forests, Temperate Rainforest and Palm Trees both produce +2 oxygen/atmosphere per turn instead of one, and they have good prestige values. Meanwhile, in the areas that will never get any rainfall, you need a Cactus. (Keep an eye out for the Cloud Seeding project so that you can boost the rainfall in a city where you want to put some plants that have a nice prestige bonus.)

Animal wise, Arctic Rabbits have a low oxygen requirement and a 6-turn cooldown (most animals have a 10-turn cooldown). This makes them ideal for establishing a first foothold with lifeforms. Birds of Paradise have a +3 temperature requirement, but only need 1 oxygen level, and their +15 support bonus stacks with their 16 points of prestige to make the first one worth 31 support/turn if you put it in a city zone. Penguins don't have a heat requirement, but they require 2 levels of oxygen so they're a bit niche. Lions are the most prestigious animal in the game (35 prestige) while Elephants are the highest prestige animal that doesn't come with a quality of life penalty (32 prestige).