Evolution is a trip in more ways than one. That life can adapt to its environment, to make a series of improvements to help it thrive in the world is amazing. Even more incredible is the way the same destination can be reached from different starting points.
It makes sense that more than one creature may evolve to have a certain ability like camouflage or venom. But sometimes nature goes even further than that. Sometimes the same thing will evolve in totally different organisms that have nothing to do with each other.
10. Nature Loves Making Crabs
It can never be overstated how much nature loves crabs. People love them too, but usually with butter and that’s a different kind of love. In nature, crabs are so beloved that they have evolved multiple times in an example of parallel evolution gone wild.
The process of something evolving into a crab is called carcinization which in and of itself is impressive. It happens so often it got its own name. Depending on who you ask, crabs have evolved 5 or 6 separate times.
There are true crabs which are the kind you’ll find on various restaurant menus. There are also false crabs which evolved from more lobster-like ancestors. These include hermit crabs. Then there are dromiidae or sponge crabs, tiny porcelain crabs, Red Lobster all-stars King crabs, and chunky little hairy stone crabs.
Science can’t fully explain why so many creatures evolve into crabs but the clearest answer seems to be that it makes sense. There are advantages to the shape and design of a crab that are superior to what the ancestors of those creatures had going for them. Or, in other words, crabs are better designed than crustaceans with different body types and attributes.
9. Caffeine Production Evolved in Coffee, Tea and Other Plants
Humankind loves caffeine, it’s the most consumed psychoactive substance in the world. We put it in drinks and snacks but most often enjoy it where it naturally comes from – coffee and tea. Except those aren’t the only sources of natural caffeine in the world, either.
Caffeine evolved, on its own, in multiple plants that have no biological connections to one another. Not just coffee and tea but cacao which allows chocolate to have a dose, yerba mate, and around 60 other plants in total.
Though the chemical process of making caffeine in plants is similar from one plant to another, research has shown that in coffee and chocolate the enzymes that evolved to make caffeine weren’t related.
When it comes to tea, after the genome of coffee was unlocked, scientists could determine that the two beverages came by their caffeine through totally different genes. While the enzymes were different between coffee and other plants, this basic genetic difference shows a completely unrelated process between the two plants.
8. Six-Legged Bodies Evolved Twice
For most people, anything with six legs is considered an unwelcome guest in the house, on a picnic, or anywhere else. There are very few bugs in the world that are well-liked by anyone and even the ones we do like — honeybees, for example — we still don’t want to get up close and personal with.
Nature has a different outlook for insects. So much so, in fact, that the 6-legged form may have evolved two different times. This is in contrast to the previously held belief that ancient insect ancestors had many more legs, like centipedes and millipedes, and the 6-legged variation is a relatively new trend in evolution.
Insects and crustaceans shared a common ancestor. This branched to produce hexapods, which includes our six-legged insect friends.But study of the mitochondrial DNA of some organisms, in particular collembola or springtails, shows they branched off from crustaceans well before other insects did.
7. Teeth Evolved In Different Times and Species
Teeth aren’t something we spend a ton of time thinking about. You think about brushing them, you’ll definitely think about them when you break or lose one, and you may notice a nice smile. But thinking about where they came from in an evolutionary sense is not big on most peoples’ to-do lists.
Evidence has suggested that teeth didn’t all come from the same place. They may have evolved at two different times in evolutionary history for both fish and mammals. With mammals, it looks like the first to evolve teeth, which would have been tiny, shrew-type creatures, happened twice. Creatures in both the northern and southern hemispheres, totally separate from each other, seemed to have evolved molars at the same time. Previously it was thought that tribosphenic molars, which can both cut and grind, only evolved in the northern hemisphere. But fossils from Australia and Madagascar contradict that.
Under the water, fossilized fish called placoderms have shown that the idea that teeth came from one single vertebrate ancestor may also be untrue. Well before the mammals, these fish were sporting chompers 408 million years ago. One branch of their family tree evolved from ridges of tooth-like material to separate, cone-like protrusions made of dentine, also known as teeth,
6. Dinosaurs Evolved the Ability to Fly Several Times
Most people seem on board with the idea that chickens and other modern birds can trace their lineage to dinosaurs. The ancient lizards evolved wings, and some learned to fly and here we are today deep-frying them.
The reality of the evolution of flight is not so simple as a T. Rex becoming a chicken. Fossil evidence shows that flight may have evolved in more than one time and place. The ancestors of modern birds is obviously the one we already know, but prehistoric raptors in South America also indicate that they evolved the ability to fly as well.
Later research into the ancestors of birds showed that the branch of dinosaurs that led to modern birds, deinonychosaurs, had potentially evolved the ability to fly at least three times. Scientists had to look at bone size and other physical traits that mirror what we know about birds today and determined a small dinosaur in the southern hemisphere called Rahonavis would have been able to fly, as would the four-winged Microraptor.
It’s likely that many feathered dinosaurs probably could glide, but those that could flap wings and take off to fly were relatively rare, just not as rare as we thought.
5. Red Blooded Vertebrates Evolved Twice
Red blood is a staple of vertebrates. If you have a spine, you probably have red blood with a few unusual exceptions like green-blooded skinks. That aspect of our existence, that the iron in our hemoglobin causes blood to be red, is usually never questioned. It seems like one of our basic building blocks and once you know why blood is red, there’s not much else to it.
Because the way blood transports oxygen through an organism is pretty efficient, it’s easy to imagine that it’s also not an exclusive method from an evolutionary standpoint. Research shows that red-blooded vertebrates managed to evolve two different times about 500 million years ago. While most vertebrates, including humans, came upon red blood to transport oxygen the same way, there are jawless fish, like lampreys, that came upon it through another method entirely. The ancestors of the fish developed an entirely distinct set of proteins to manage oxygenated blood.
4. Venom Has Evolved at Least 100 Separate Times
The world is full of dangerous animals. Some are dangerous because of their teeth and claws but others have developed effective weapons in the form of venom. Different venoms cause different reactions. Neurotoxic venoms affect your nervous system while hemotoxic can go for your heart and make you bleed out. You can be exposed to venom from snakes, fish, spiders, insects, amphibians, and even some mammals.
Venom systems have evolved over 100 times across these various life forms, making it one of the most prolific evolutionary traits in the world. The evolution is as complex as it sounds. Some venom is related to digestive enzymes, others are not. It can be transmitted through skin or fangs or stingers depending on the animal. The origins are still steeped in mystery.
3. Wolves May Have Evolved Into Dogs In More Than One Place
That modern dogs evolved from wolves about 130,000 years ago and they were domesticated about 12,000 to 15,000 years ago is fairly well known. Less well known is that this may have happened more than once. The domestication of dogs may have happened in both the East and the West, turning wolves to dogs in two unrelated places.
In the past there has been disagreement about whether domestication occurred in East Asia, Central Asia or Europe. But all three could be correct. Comparisons of ancient dog DNA found in skeletal remains shows that Eastern and Western dogs are genetically different and may have come from different evolutionary trees.
Another study conducted later revealed that dogs from the Middle East and Eastern Asia also have different genetic origins, meaning separate wolf populations likely gave rise to each. Theoretically that could mean wolves evolved into dogs in several places.
2. Life Itself May Have Evolved Multiple Times
Let’s go back further than ever before. Not to the evolution of teeth or eyes or fur or bones. Let’s go all the way to the moment life started and ask a question. Was there one, specific moment when life evolved? Or did it happen a lot?
Science has proposed that it’s possible there was no single moment when life began. Instead, life may have started over and over and over in multiple, unconnected places. The earliest life, in its simplest forms, could have been spreading like wildfire in all kinds of unique and diverse ways. And maybe it was only our first mass extinction event that many of these were wiped out, paving the way for far fewer options to take over in the place of what was lost.
For a long time there was a belief that all life on Earth, no matter what form it took, could be traced back billions of years to one microorganism that would have been the progenitor of everything. But this alternate theory presents the possibility that there was no single common ancestor at all.
The presence of life that exists outside “normal” conditions lends credence to this theory. Things that thrive in harsh, deep ocean vents, or the darkest sealed corners of the world. The microbes there, which are rarely studied, could be parts of totally separate trees of life.
1. The Aldabra Rail Went Extinct But Then Evolved Into Existence Again
So far we’ve seen several examples of convergent evolution which gave rise to similar shapes or aspects for organisms, but there is nothing else like the Aldabra rail. This is an entire bird that evolved, existed, went extinct and then evolved again from a different bird.
The original Aldabra rail was a flightless bird that lived on the Aldabra atoll in the Indian Ocean. It was not entirely remarkable other than by virtue of being flightless, which is the reason it could not survive the flooding of the atoll 136,000 years ago. The flood wiped all terrestrial life on the atoll out and the rail went extinct.
Fast forward to 36,000 years ago. An ice age altered the landscape of the world and ocean level’s dropped enough to bring the atoll back. Over in Madagascar, a bird called the white throated rail took flight and left the island, settling on the Aldabra atoll. This same thing happened once in the past as this same bird, long in the past, left Madagascar and settled on the atoll where, over time, it evolved to be flightless and became the extinct Aldabra rail.
With a new population of white throated rails, nature followed the same path as before and the rails once again lost their ability to fly. The Aldabra rail had evolved back into existence for a second time.
Comparisons of bones between the new flightless rails and the old flightless rails and the flying white-throated rails show the extinct and the new versions are very similar and distinct from their flying ancestors, with thicker ankles designed for walking and a heavier overall structure not ideal for flight.