Backstage Reply Book Title One Click Free Reading: Origin of Species | White Deer Plains | Brother | ......
Warm reminder: Friends who are afraid of rats are recommended to read the text carefully, this article is very interesting and will make you forget about being afraid of rats. Originally, there was also a snake part that was afraid of causing discomfort, so it was slightly deleted.
01
When it comes to interesting evolution, how can we not mention convergent evolution phenomena, such as this?
If you take this picture to the street and ask someone what it is, there is probably a good chance that it will be said to be a mouse, but this is a shrew, not a mouse.
It has to be said that the shrew does look too much like a mouse, but it is not related to the mouse, the mouse belongs to the rodent order, and the shrew belongs to the order carnivorous, which is 18,000 miles away at the taxonomic level, but because of the same ecological niche, it is a striking similarity in the evolution of the two animals that cannot be beaten by eight rods.
Although it is very similar to mice, the difference can still be seen in appearance, the most significant difference is that the shrew is much smaller than the size of the mouse. The shrew is the smallest mammal in the world, it's not even as big as your fingers, and rats are huge compared to them.
But even so, many people will mistake the shrew for a juvenile mouse and stomp to death, so it is unknown how many shrews have died at the hands of humans.
In addition to differences in body size, there are other significant differences between shrews and mice, such as the shrew's mouth is pointed, while the mouse's mouth is blunt, and the shrew's head to body ratio is much larger than that of mice.
But even so, the appearance is still difficult to distinguish ah, don't worry, although the appearance is difficult to distinguish, but if you look at their bones, the difference is clear at a glance.
Teeth are the most valuable bones in animals, and many useful information can be read through them.
Rodents, including rats, have unusually developed incisors that are used to nibble;
However, the shrew's incisors are not developed, but instead have sharp teeth, exposing that it is actually a ferocious carnivore.
Warm reminder: there are earthworms in and out below
Of course, this ferocity is for small insects, because the size is too small, the shrew can not catch anything other than the insect, we see the small things in their world are very huge, even an earthworm is like a giant python.
Because of its small size, sometimes the shrew will even be killed by insects.
But we still have to pay the highest respect to this humble little animal, because the insectivorous order is the oldest placenta of eupropodic mammals, which appeared as late as the Cretaceous, and is the ancestor of all placental mammals.
This is a giant skull beast that lived more than 100 million years ago, almost the size of a paperclip, almost exactly the same as today's shrew, and the world they lived in at that time was the era of dinosaurs, what were the dinosaurs like at that time?
This is the vertebrae of a giant sauropod dinosaur of the Cretaceous period, and the height of a single vertebrae alone is more than two meters, and it is conceivable that when it was still alive, what kind of existence it was when it was still alive, in the period when the world was dominated by dinosaurs weighing several tons and tens of tons, this paperclip-sized and weighing only a few grams of small and humble mammals was faced with a sense of despair and suffocation on a daily basis.
However, this humble little animal endured humiliation and burden in the shadow of the dinosaurs, survived hard for tens of millions of years, and finally survived the dinosaurs to extinction, becoming the final winner of the survival war between the bow and the lizard that lasted for 200 million years on this occasion, and when the hector was almost completely destroyed, it struggled to the end, and overturned in one fell swoop, overturning the rule of the lizard for more than 200 million years, regaining the throne that belonged to the heaphopod, so that the arch and the arch once again became the dominant species on the earth after 200 million years.
Today's whales, elephants, tigers, cattle, horses, sheep, cats, dogs, including our own humans, are all derived from this humble and strong ancestor.
So in Zootopia, the character of the most powerful big man gives this smallest mammal, and it is also a kind of respect for the humiliation of our ancestors. The order Carnivorous is well deserved as the godfather of mammals.
02
Of course, convergent evolution is not limited to shrews, there are many long-like animals that resemble rats, and they are not actually rats.
For example, moles, insectivores.
For example, bats, pterodactyls, some people say they are winged mice, but they are not.
For example, armadillos, armoured mussels, walking sushi.
For example, the tasmanian mole, which is more distantly related, has a marsupial class.
Another example is the possum, which has marsupials.
For example, the possum, although it looks a bit like a squirrel, is actually a marsupial
For example, the possum, although it looks a bit like a mouse and a rabbit hybrid, but in fact it still has a bag
Also, musk kangaroos, still marsupials
One might ask, is it that only marsupials are so fond of evolving into the appearance of rats, of course not, such as this one.
The hoofed rabbit, the order Hoofed Rabbit, belongs to the eupropodic mammal with placenta. Although the cargo looked like a marmot, the two fangs revealed that it was actually a distant relative of the elephant.
However, the elephant said he did not know the relative.
Well, you can't accept that? I haven't said you have a distant relative living in the sea.
Sorry, misplaced the picture, this is:
Although this guy is called a manatee, it is actually more appropriate to call it a walrus, because the closest thing to it is an elephant on land, although the elephant may not accept it for a while, but it is true, you see you all eat the same way
03
Pull far, pull far, and then say rats, many animals like rats are not rats, but many animals that look like they can't fight with rats, but they are really rats, such as this one.
The porcupine has a hard thorn and an extremely grumpy personality, and if you accidentally provoke it, you may become like this,
No matter in terms of size, appearance, temperament, and porcupine, it is not related to the cowering mouse, but these two developed incisors still expose the essence of its rodent order, and the porcupine is essentially a large rat with thorns.
As a rodent, the porcupine achieved the counterattack of the mouse against the cat for the first time.
So aren't there big and gentle mice? Of course, this has to mention the good old people of the animal kingdom, the capybara king who is loved by everyone.
Don't be fooled by its name, the capybara is not a pig in the water, it also belongs to the rodent class, in fact, it is still a big rat.
However, capybaras are not always so cute, such as the prehistoric capybara found in Uruguay, with a skull fossil of 53 centimeters long, speculating that the height may reach 1.5 meters and the weight may reach a ton.
That is to say, this is a rat larger than a cow, inexplicably terrifying.
High-energy early warning
Don't be afraid, because the cats at that time were like this
Far from it, or back to convergent evolution, what causes animals that are not related at all to look so similar?
Because they are in similar niches in similar living environments, this causes the two animals to evolve towards the optimal solution suitable for this environment, and the optimal solution in the same environment is often the same, so they will also evolve striking similarities, a phenomenon that abounds in nature, not just mice.
Convergent evolution is not limited to today's organisms, but even in paleontology, the shadow of convergent evolution can be found, if you see a fossil of such an animal.
You would think it was some kind of prehistoric turtle.
However, it is not, this is an animal called a dragon that lived in the Triassic Period 200 million years ago.
It even evolved a hard carapace even earlier than a turtle.
In a way, it is not that it copied the turtle, but the turtle copied it.
It looked like this after it was restored.
Although it looks like a strange turtle, it is fundamentally different from a turtle.
The biggest feature that determines that it is not a turtle is its teeth, and the mouth of the dragon is full of these very strange stone-like teeth, hence the name " Plesiosaurus " , while the real turtle has no teeth in its mouth.
In addition, the hind legs and waist of the dragon were leaked out of the carapace, while the turtle's dorsal carapace wrapped around the entire body.
A more obvious difference is that the dorsal carapace of turtles is made up of regular large pieces of carapace, while the dorsal carapace of a dragon is a pile of small pieces of carapace.
In an era when the dragon was about to become extinct, the fossils of turtles appeared, most likely due to the competition in the same ecological niche but more advanced body structure of the turtle, the dragon was eliminated miserably.
Like snakes, the shape of the turtle is a very successful design, so it has appeared many times in nature, and in addition to the 200 million-year-old plesiosaur, mammals have even appeared similar designs.
The echinodonts lived in the Americas more than 30,000 years ago, and they also evolved turtle-like dorsal carapace, even harder than tortoise carapace, and their size can reach two tons, much larger than a turtle.
So much so that the Indians who had just arrived in the Americas were puzzled by this strange "big turtle".
But they immediately discovered the animal's uses, so they transformed their shells into houses, and the animal went extinct.
But they still have relatives who live to this day, and that's the armadillo that lives in the Americas.
But armadillos seem to prefer to turning themselves into a tide worm than to prehistoric relatives who want to turn themselves into turtles.
04
Speaking of convergent evolution, of course, there are far more than the above mentioned ones, and similar examples of the evolution of animals in nature over hundreds of millions of years of time abound, such as this one.
The Triceratops, which lived in the Cretaceous Period, is easily reminiscent of an animal that is still alive today.
The long horns on the head are also a successful design, which not only brings strong defensive capabilities, but also makes the image instantly powerful and domineering.
Naturally, such a windy design will not appear only once, and the chameleon who likes to show off naturally cannot let go of this excellent tool.
Even some beetles have followed suit
Even in mammals it has appeared independently many times.
Thunder beast, living more than 30 million years ago in the Eocene, also has a big horn on its nose, although this cargo looks like a rhinoceros, but the animal closest to him is a horse.
And what was the rhinoceros like at that time? such.
This thing is called a running rhinoceros, and although it looks like a horse, it is a real rhinoceros.
It was a time when everyone took the wrong script, and horses looked like rhinos, and rhinos looked like horses
However, the more pit daddy is still behind, and the running rhino probably also feels that he has grown up like this a bit to shame the rhino family, so he is ashamed and brave, and the longer he grows, the bigger he becomes, and he accidentally grows like this.
The giant rhinoceros, which is more than 7 meters tall and weighs more than 20 tons, has not only grown to become the largest member of the rhino family, but also the largest mammal that has ever appeared on land.
Even if you can only see the fossil now, you can still feel its shock.
05
Convergent evolution occurs not only on land, but also in the oceans.
For example, this:
Ichthyosaurs that lived in the Mesozoic oceans 200 million years ago bear a striking resemblance to the evolution of dolphins living in the oceans today.
As a star species in ancient creatures, the appearance rate of ichthyosaurs is really a bit bad, even children know it.
But today is not to talk about this, first look at a few pictures.
Sharks, cartilaginous fishes:
Tuna, teleost fish:
Ichthyosaurs, lizards:
Dolphins, mammals:
Humpback whales, mammals:
Dugong, mammals:
Beavers, mammals:
Platypus, mammals:
After reading so much, have you found a phenomenon, are all animals living in the water, why are bony fish, cartilaginous fish, or reptiles, their tail fins are upright, and only the tail fins of mammals are horizontal?
what? Didn't pay attention? Go back and look at it again.
These mammals live in different parts of the world, and do not come from the same ancestors, dolphins and whales from the order of even-hoofed, manatees from ancient condyles, beavers from rodents, platypus are more distant, from the more primitive columnar orders, but why did they invariably evolve a flat tail?
06
And with the exception of mammals, why has the tail of this shape never appeared in any other animal?
The answer to this question is not actually on the tail, but on the spine.
Seeing so many graphs, you should be able to sum up two points.
First, they are all mammals; second, they can all shrink into a clump.
And this seemingly easy action, but only mammals can do it, because only mammals have vertebrae that can bend back and forth, while other animals, fish, amphibians, reptiles, their spines can not be bent back and forth, can only bend left and right.
The way the spine is bent brings different ways of movement, and only mammals can land on all fours and use the spine to bend back and forth and run at high speed.
This spine can also be used to bounce.
Even do a lot of difficult moves.
Reptiles, on the other hand, can only bend their spines left and right, so they can only shake their heads and tails and twist their waists to climb forward.
Therefore, when mammals returned to the ocean, they also used this way of bending back and forth of the spine, and eventually evolved a flat tail fin. Other animals can only bend the spine left and right, so they have evolved a matching vertical tail fin.
And the reptile found a problem, this kind of left and right curved spine greatly limits the speed of movement, crawling on four legs is not as fast as running on two hind legs, so when encountering danger, lizards will choose to raise their forelimbs and flee with two hind legs.
When the lizard is frightened, it will choose to run away
In fact, reptiles have discovered this problem as early as 200 million years ago, and reptiles have chosen this way of moving 200 million years ago.
So their hind legs became more and more developed, and the front legs became shorter and shorter, so you should be able to guess what they became later.
To add, on the question of the way the spine is bent, the previous statement is not too rigorous, reptiles are not vertebrae can not be bent back and forth, it should be that the spine of the trunk part can not be bent back and forth, reptile cervical vertebrae are very flexible, especially the ornithocenae archosaurs and their offspring cervical vertebrae are even more flexible than mammals.
Gaga clams?
A lazy owl
Birds that are descendants of the ornithopod archaic have very flexible necks, and owls can even twist their necks 270 degrees in any direction, and any mammal that does this will break its neck.
But this is not of any use, the flexible cervical spine does not help with movement, and the spine of their trunk is still very stiff and cannot be moved back and forth.
It has also been mentioned that not only mammals can shrink into a clump, but indeed some reptiles and amphibians can shrink their bodies into a clump, but their so-called shrinkage is completely different from that of mammals.
You should be able to see that they are actually shrinking their bodies sideways into a ball, rather than bending forward like mammals, essentially because their spine in the trunk part cannot be bent back and forth, so they can only pose such a twisted shape, and it seems to be very laborious.
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