When nature beats you to the punch

World builders often have startling capacities for imagination. Yes, you need to think hard to, say, design realistic geography for a planet, or create a new language, but even so, we have biases arising from our own experiences. In some ways — small ones, perhaps — we remained bound by what we observe around us on Earth.

Coming up with new life-forms, whether carbon-based or not, requires a bit of ingenuity. Sometimes, people come up with really good ideas, like biological radios or animals that turn their exoskeletons into shields. They want to know whether these putative creatures could really exist, and so they ask us. A lot of the time, we have to do a bit of theorizing, based on biological principles and some informed guesswork. A surprising amount of the time, however, we don’t have to do any guessing, because — against the odds — that really weird creature you dreamed up actually exists.

I like reading answers to questions like these; they’re some of my favorite reality check posts on the site. I’m going to talk about five of my favorite ones (in no particular order). Perhaps you’ll find some inspiration in them.

Is an organism with both animal-like traits and plant-like traits scientifically possible?

This is, I think, an age-old question, and one that seems to crop up from time to time on the site, in different guises. In most cases, when people think animal/plant hybrid, they think of essentially an animal that is capable of photosynthesis. For many animals — such as humans — this isn’t really feasible, because it would require a really high-efficiency reaction. Smaller animals, though, have some potential.

What really intrigues me, though, is that the author of the question talks about anatomical and structural differences. For instance, plants have cell walls, while animals don’t. Is it possible that such rigidity could be utilized by an animal? Or could a plant benefit from bones and muscles, like a stronger Venus flytrap?

Elysia chlorotica is kind of cute, right? Image credit: Wired.com.

Well, those questions remain to be answered. However, Laurel found an excellent photosynthesizing animal, a lovable green sea slug called elysia chlorotica. The slug has an interesting digestive process: It eats algae, but keeps the chloroplasts from its food. Under good conditions, the chloroplasts can last for months to a year, well-integrated into the slug’s body.

Beautiful? Maybe. Elegant? Perhaps. Brilliant? Oh, absolutely.

What kind of natural armor would stop bullets?

The world outside our houses is a scary place. Thousands of years ago — or, honestly, a few centuries back — you’d be lucky to get a few decades to live. Given the number of things you could die from, that’s not too surprising. In the wild, any creature has to worry about predators, disease, starvation, natural disasters, and, at the moment, humans.

One of the reasons (though not the only one) that we humans pose a threat to animals is that we have an unfortunate penchant for shooting them, often merely for sport. From the animal’s point of view, it’s more than a bit of an unfair fight; you don’t see many deer walking around wearing bulletproof vests. But what if they did, in a sense? This was, basically, one user’s idea. Could it work?

Green performed an analysis and concluded that Mother Nature has already done some field testing. The mantis shrimp has claws with incredible agility and strength; even if they miss their intended target, the shock wave alone can knock out or kill an opponent. They can, in a sense, attack with the wave of a hand.

Aside from being quick, these claws are durable. They can withstand pressures of up to 4 gigapascals, which should be more than enough to withstand a bullet (by a lot!). I, for one, would not want to take on a mantis shrimp. It would be, by any standard, a bit of an unfair fight.

PipperChip pointed to a slightly meeker creature, the abalone. Abalone are actually a group of sea snails and related animals— kind of the opposite of the mantis shrimp. Their shells are made of tiles of calcium carbonate, a common shell-building material. The important ingredient, however, is the mortar between the bricks. A protein “glues” the tiles together in an orderly fashion, and provides stability and structure in the case of an impact, allowing it to more efficiently dissipate energy.

Apparently, tests have been done on abalone shells, and apparently, the shells have survived. I wonder who would win in a fight between a mantis shrimp and an abalone. . . .

A three foot cell?

Most of the complex creatures on Earth are built out of a number of different cells, most specialized to perform a certain function, whether that be digestion, respiration, thinking, or something else. In general, larger organisms have more cells, while smaller organisms have fewer — and, likewise, organisms with more cells are usually larger, while organisms with fewer cells are smaller. It’s a simple necessity.

One user wondered if it was possible to have an exception to that rule — and it turns out that it is. What’s more, there are many such exceptions wandering around the planet. Ray O’Kalahjan found a few:

  • Valonia ventricosa is a type of single-celled algae found around the world that can grow up to two inches in diameter (which is, for a single-celled organism, quite impressive!).
  • Acetabularia, another type of unicellular algae, can also grow up to several inches. It has a surprising amount of structure
  • Xenophyophores (courtesy of another user, Nathaniel) are a class of deep-sea organisms that can be 2–3 times the size of the other two. Like valonia ventricosa, they are abundant the world over.
Is it a balloon or a green apple? Valonia ventricosa in its natural habitat. Image in the public domain.

Somewhere in the range of three feet is a bit much for a single cell. But 8 inches? Look no further than our own oceans — although you might have to dive down a couple kilometers.

Acetabularia, the flowers of the sea. Image credit Wikipedia user Tigerente under the Creative Commons license.

Multiple DNA, one creature

When designing a being, whether alien or Earth-bound, world builders seem to enjoy playing around with an organism’s genetic code. Sometimes, that can involve modifying one or more of the base pairs in DNA, or recreating the chemical structure from scratch. However, you don’t have to go that far to come up with something completely novel. In this question, a user proposed splitting the information contained in DNA into a couple strands, each with its own purpose.

As you might have expected, yes, nature has already tried this out — and succeeded. A couple different answers, with some overlap, attacked the problem at multiple angles. Joe Bloggs noted that mitochondrial DNA exists in humans, and does control various processes. Serban Tanasa came up with an exotic example, namely, chimeras, which possess groups of cells with different genetic codes (trichoplax raised a good counterpoint, which is that chimerism isn’t heritable).

My personal favorite answer there comes from QuadmasterXLII, who selected a modest choice: lichen. Lichen is the result of a symbiotic relationship — one where two different organisms benefit from a shared lifestyle — between algae and fungi. Wikipedia notes that lichen may cover up to 6% of Earth’s surface. That’s pretty impressive for a fairly modest creature.

Can a rational creature have a series of small brains instead of a large one?

Wouldn’t it be nice to have more than one brain? Evolutionarily, it sort of makes sense; you have, in a tenuous sense, redundancy — trauma to one brain would still leave the others working just fine, although certain brain functions would be damaged. Sure, you increase the complexity by adding more brains (the network of neuronal pathways would be staggering), but hey, complexity could be a fair price if environmental factors demanded it.

An octopus has pretty smart arms. Image credit: Henrik Sorensen, Getty Images.

On our planet, it seems like nature has largely settled on giving most species one brain. Fortunately, not all organisms fit the mold. A few of us (myself included) noted that octopi have neural tissue in their arms that can act independently of the brain, if needed. Granted, these structures aren’t well-developed in the same way that a proper brain is, but they do work.

I also came up with a different variant: leeches. They have one ganglion — a group of neural cells — within each segment. Now, they don’t operate entirely independently of one another, but they do indicate that, structurally, having multiple bunches of neural tissue is quite feasible (if the octopi didn’t convince you).

Well, that wraps up my survey of some of nature’s most ingenious ideas. These questions are part of why I love Worldbuilding Stack Exchange so much: there’s a surprise around every corner. That, in a sense, mirrors our world. Nature can surprise us time and time again.

For more awesome questions in this vein, check out the biology and xenobiology tags on the site. You’ll be amazed at what you find.