The First Animals Were Living Fractals (maybe)
Ancient fossils are illuminating the earliest multi-cellular life that was big enough to see with the naked eye. They may have been the first animals ever and they were Fractals!
These creatures are called Rangeomorphs and they are now in my top 10 list for the coolest animals ever.
The geologic period that saw them briefly flourish is called the Ediacaren which lasted from around 635 to 541 million years ago. This period is somewhat opaque to scientists since life-forms from that time had no easily fossilized hard shells. This was because such structures hadn’t even evolved yet.
Not only that, most of the structures we think of as kinda important for animals hadn’t evolved yet either. There were no legs or internal organs or nervous systems or even mouths…anywhere…on earth. Yet these creatures were cutting edge biotechnology because they were among the very first multicellular life and they were big, anywhere from 10 centimeters to 2 meters. The rest of the world was composed of single-celled organisms so the Rangeomorphs were pretty much at the top of the life heap.
You may think these buggers were plants considering they looked like plants and had no motility. That would seem reasonable except for the fact that they lived far too deep in the ocean for photosynthesis to do its magic. Eating appears to have been a very passive affair for these creatures. Nutrients that happened to wash over their membranes would be absorbed. This was actually fairly efficient at this point in earth’s history. The oceans were truly a nutrient-rich primordial soup, much more so than today. It wasn’t chicken noodle soup but all the organic carbon floating around made for tasty treats. (not very tasty I guess since taste-buds hadn’t evolved).
This couch-potato eating style appears to have been facilitated by the body plan of the rangeomorphs. Surface area needs to be maximized if you can only absorb food that happens to run into you. This is exactly what their fractal shapes excelled at. Fractals are shapes that exhibit self-similarity. Tiny parts of them look like the whole. They are therefore scale-invariant, meaning no matter how close or far away you are, they look pretty much the same. These shapes are found all over nature from coastlines, mountains, clouds, lungs etc. They also fill up space with incredible efficiency which is why lungs can be relatively tiny yet have a surface area of 90 square meters.
So things were going well for the first animal-like creatures for millions of years until there was an explosion….the Cambrian explosion. This milestone in the fossil record records a period in time when evolution took a stab at a plethora of different body plans (phyla) for its new and improved animals (animalia 2.0 if you will). Many of these designs weren’t successful for long but many were and, in fact, they account for almost all animal body designs that exist today.
These new animals kicked ass and they weren’t out of bubble-gum either. Not only were they gobbling up the ocean nutrients but they also could hunt and move and they had shiny new exoskeletons to back them up. The poor rangeomorphs didn’t stand a chance. Nutrient availability went into a steep decline and these bio-terminators from the future could totally kick their asses (and probably eat them as well). Bye bye rangeomorphs
It’s still controversial exactly what rangeomorphs were. Most scientists think they were animals but some still think they were more like algae or lichens. My favorite other possibility is that they simply belong to a completely different kingdom of life. I wonder what they’d be like today if the last 1/2 billion years went their way.
Image Credit: Jennifer Hoyal Cuthill (University of Cambridge)