Evolution is a fascinating process. Any life form, from lowly sponges to massive whales, can testify to how adaptation has worked to its advantage over many generations. Sometimes, an adaptation works so well that it becomes a defining characteristic of every branch of that life form's family tree. Other times, they likely fail and die out. But the truly fascinating thing is when evolution rolls the dice a second time. Some trait, some adaptation, arises in one life form, and then a completely separate life form, barely related, if at all, independently develops similar traits. And this happens more often than you might think.
10. Things continue to develop into crabs in a process called cancerization
Science has some bad news if you're not a fan of multi-legged, crawling life forms that scurry around and have claws. Nature wants everything to be crabby. In fact, nature wants things to be crabby so much that we have a word for it— carcinization . It's a process of evolution from a non-crab-like creature into something crab-like, and it's ongoing.
While we needn't fear that we'll one day evolve into crabs, this process appears to be affecting creatures that began life in a typical "crab-like" space. That is, crustaceans like lobsters and hermit crabs, which weren't originally crab-shaped, are evolving toward crab-like forms. This has happened. three times in a group of crustaceans called anomurans. What they evolve into isn't technically a true crab, they can't change species, but they do become crab-like . I think you saw a crab.
King crabs, those long-legged buffet staples around the world, are a case in point. The Kamchatka crab is not a true crab, but a decapod anomurana. Its ancestors were actually hermit crabs . Hermit crabs have to use the shells of other marine creatures because they have a very soft exoskeleton, so their evolution to the king crab, which has a truly robust skeleton, is quite dramatic. Other examples include porcelain crabs and hairy stone crabs, which are also not "true" crabs. But their path to the crab world was independent and a very unusual example of convergent evolution.
9. Pitcher plants evolved independently at least six times.
Pitcher plants often fascinate people more than the common garden flower, if only because they're carnivorous. The idea of a stationary life form feeding on other life forms is unique. Or so it seems. However, evolution seems to be quite fond of this concept. So much so that pitcher traps evolved completely independently of each other, at least, six times . These plants belong to different families, including bromeliads, where you you will find pineapples .
Unrelated lineages of carnivorous plants are most prominent in three families . These plants shouldn't be confused with the Venus flytrap, which captures prey using a different mechanism. Instead, pitcher plants are defined as a kind of cup containing digestive fluid. Insects or other nutrient sources are drawn into the cup, often thanks to a slippery surface that evolved independently in most species, and fall inside. Different biological backgrounds exist.
8. Three-toed and two-toed sloths are not closely related.
The internet loves a good sloth video, and why shouldn't it? Sloths represent the ideal life for many people. They relax, unwind, eat, and sleep. It's enviable in its own way. And we even have two sloths to choose from: a three-toed sloth and a two-toed sloth. While both are known for being incredibly slow, living in trees, and hanging upside down, it's also clear that they don't look much alike.
The two-toed sloth is the shaggier of the pair and is related to a giant prehistoric sloth called Megalonyx and Mylodon darwinii . Three-toed sloths are more closely related to Megatherium. But like the three-toed sloth, the two-toed sloth evolved to live upside down in trees, although none of his major ancestors did this did. And this means that this arboreal life is a defining characteristic of both species, which evolved independently. If the two species shared a common ancestor, scientists aren't sure when it might have been or what kind of creature it was. Their best guess is that if it did exist, it certainly didn't hang out in trees.
7. Falcons are more closely related to parrots than to eagles.
Many people are afraid of birds, and Alfred Hitchcock knew this well. It doesn't help much when scientists tell us that dinosaurs evolved into birds, so essentially every chicken is a tasty T. rex.
In the world of birds, some are definitely more frightening than others. Birds of prey are naturally terrifying, thanks to their flesh-rending beaks and talons. Hawks, eagles, and falcons seem to have speed and ferocity on their side. But the unusual thing here is that falcons are not like those two. Despite how easy it is to confuse a falcon with a hawk, they are only distantly related and are another example of convergent evolution in action.
Rather than being closely related to eagles, falcons are actually much closer to parrots . That the peregrine falcon is literally the fastest creature in the world , closer to a parrot than an eagle, seems somehow wrong. Despite this, DNA evidence proves that the two birds' common ancestor is much more closely related to each other than other birds of prey.
6. The eyes of humans and cephalopods are very similar
Every year it seems like new research proves that octopuses are surprisingly smart animals, and we do them a disservice by ignoring this fact. However, it's not just their brain that is unique; almost everything about octopuses as a species is remarkable. Take their eyes, for example. They work like this same as and human eyes, but it is quite clear that they evolved completely independently. The same can be found in other cephalopods, such as squid. Somewhat more remarkable is that behind our backs, both we and they are responsible for the same things the same genes .
There's a gene called Pax6 that controls the basic structure of the eye in almost every creature. It's found in a wide variety of animals, meaning it predates evolutionary diversification. So, it's been around for over 500 million years. Think of it as a master gene that governs eye formation—it could be the complex eye of an insect, the eye of a lizard, the eye of a bird, and so on. But when it comes to humans and cephalopods, each has evolved a very similar structure, which we call a camera eye. It has a lens, an iris, a fluid-filled interior, and so on. And after 500 million years and two species, one on land and one in the sea, convergent evolution has created the same basic structure in both.
5. New World and Old World vultures are not closely related.
In the world counted 22 species birds called vultures. You can usually recognize a vulture as a fairly large bird, usually bald and prone to scavenging. Generally, by human standards, they seem a bit rough, as their heads are constantly buried in rotten carcasses, but they actually do a great service by cleaning out all that toxic, bacteria-ridden meat, so don't be too hard on them.
These 22 species of birds can be divided a little further into Old World and New World , that is, the vultures found in Europe, Africa, and Asia, and then the vultures found in North and South America. Despite the striking similarities between the New and Old World species, there are genetic differences indicating that many of these birds evolved convergently.
Old World vultures appear to have evolved from birds of prey, being a branch of the raptors. However, New World vultures can trace their origins back to from storks .
4. Six different lines of electric fish evolved separately
The sea is home to many unique and even terrifying creatures. One of the most unusual is the electric eel. They can generate up to 500 volts (some say 600 volts) at a current of one ampere. But this is not the only electric fish. And others with the same ability are not related to the eel. In fact, electric fish evolved independently at least six different cases . All of these animals use the same genes, they just did it around the world at different times and in different places.
While eels live in fresh water, electric rays They can be found in the Atlantic Ocean. Like all rays, they are broad and flat, almost the complete opposite of an eel in appearance. But their electrical generating abilities are very similar. And since we know that most fish are incapable of generating electricity, the idea of a common ancestor among the diverse electric species makes no sense. The ability arose uniquely and independently. It has only happened half a dozen times.
3. Sugar gliders are not related to flying squirrels.
Sugar gliders and flying squirrels are two of the most delightfully strange little mammals you'll find in the treetops. Both have wide flaps of skin under their arms that allow them to glide from branch to branch, both have long tails and large eyes, and if you didn't know much about either species, you'd probably have no idea how to tell them apart beyond a cursory inspection.
It is noteworthy that these similarities very superficial. Sugar gliders are marsupials and raise their young in pouches, while flying squirrels do not. While there are 50 species of flying squirrels worldwide, there are only 6 Types of Sugar Gliders , and they're native to Australia. Like most other marsupials, they evolved in isolation from creatures like the flying squirrel, making their similarities an example of convergent evolution. The flying squirrel is actually more closely related to primates , than with sugar gliders.
2. Humans and koalas have very similar fingerprints.
Koala bears are perhaps Australia's most memorable inhabitants, rivaling kangaroos but perhaps more popular for their adorable appearance. As cute as they are, you'd never mistake a koala for a human, as they're two-foot-tall, tree-dwelling gray bears. Koalas are marsupials and are most closely related to wombats, possums, and, yes, kangaroos. However, in a unique case of convergent evolution, their small marsupial toes have fingerprints that are so distinctive.close to human, that even experts can hardly tell them apart at first glance.
To find a common ancestor between humans and koalas, you have to go back about 100 million years back , long before Tyrannosaurus rex walked the earth. However, their fingerprints look and potentially function similarly to those of humans. Since koalas only eat eucalyptus leaves, and only certain ones at that, it's highly likely that tactile function is important for helping them choose the right leaves, and these fingerprints will come in handy. They need a precise grip and sensitivity, just like humans, so it seems their fingerprints evolved along the same lines as ours.
1. Bats and dolphins have almost identical echolocation abilities.
Bats and dolphins are as different from each other as it's possible for any two mammals in the world to be. Yet, despite their incredible differences, there's evidence that convergent evolution has occurred in both species, leading to the development of their remarkably similar echolocation abilities.
By analyzing several species of bats, as well as dolphins, scientists have discovered similar genetic signatures in 200 regions of the genome , associated with echolocation. The researchers expected to find only 10 to 30 shared genes. When they looked at bats that did not use echolocation, none of these genetic similarities were found.
In particular, bats and dolphins had mutation in protein called prestin, which affects hearing. That this mutation could occur in two very different species and have the same effect was unexpected and demonstrated that convergent evolution goes far beyond the physical adaptations we see on the surface and includes genetic adaptation as well.