When many people think of reptiles, they think of cold-bloodedness, slow movement, and low INTELLIGENCE. In the eyes of ordinary people, reptiles are almost synonymous with inferiority, and the difference between us and mammals is as clear as the definition in textbooks. However, the public's misunderstanding and contempt for reptiles is actually unscientific, and more and more experts realize that reptiles are an unscientific classification unit and advocate their abolition.
Galapagos tortoise
The taxonomy was pioneered by the naturalist Linnaeus, who classified and grouped organisms according to their different characteristics, with the intention of facilitating identification. Later, classification experts created different levels of classification units, the basic classification units have a total of eight, from large to small, domain-boundary-phylum-class-order-family-genus-species. Before the base unit, it is prefixed with "high", "total", "large", "up", or "sub", "lower", "small", to indicate a larger or smaller unit.
Now, the consensus of the academic community is that taxonomy should reflect the evolutionary relationships between species, reflect darwin's principle of common ancestor, which is systematic taxonomy. In other words, organisms that should be classified as having a common ancestor should be classified as having a common ancestor, not those with similar appearances, although organisms with a similar common ancestor usually look similar.
According to the systematic taxonomy, each taxonomy represents an evolutionary branch on the phylogenetic tree. For a given unit, a monophyletic group is a monophyletic group if it contains and contains only a common ancestor and all of its descendants; if it contains a common ancestor and some of its descendants, it is a co-lineage group; but if it does not contain the nearest common ancestor, it is a polyphyletic group.
Monophyletic, parallel, and complex groups are illustrated
Many scholars believe that a natural taxon can only be a monophyletic group, rejecting all parallel or complex groups. In recent years, with the continuous maturity of classification methods, many of the previously recognized classifications are being greatly modified, and it is in this situation that the reptile has been questioned.
Numerous living and prehistoric animals are classified as reptiles, and scientists have divided reptiles into several suborders based on the number and location of temporal holes. The temporal foramen is a hole located on the side of the skull, behind the orbit, where the masticatory muscles attach, that is, the temples.
Schematic diagram of the location of the "temples" of the missing bows, double bows, and combined bows
Diplodontidae ( Diplodontes ) have two upper and lower temporal foramen on each side of the skull , including all extant reptiles , as well as prehistoric dinosaurs and pterosaurs.
Aporous subclass (hypochondrites), without temporal foramen, including the most primitive reptiles - cup dragons, middle dragons. Turtles were once classified as a suborder , but it was later found to have temporal foramen , but degenerated , and were a basic diplodocus.
Suborder inferior foramen (zygomatic, monocodytic), with only one temporal foramen on each side of the skull, located below the posterior orbital bone, including panosaurs, theropods, etc., flourished before the age of the dinosaurs, and now there are no such animals (where did they go?). Revealed below).
ichthyosaur
In addition, a suborder (broadborod) has been established, with only one enlarged upper temporal orifice on each side, and the lower temporal temporal foramen degenerate, including prehistoric marine reptiles such as plesiosaurs and fish. It was later found that the suborder was untenable, and that the broad-arched feature was merely an adaptation to marine life.
According to modern systems taxonomy, the perfect taxonomic unit must be a monophyletic group. The reptile crown group, or true reptiles, includes the latest common ancestor of all living reptiles and all of their descendants. The extant reptiles are all suborder diplodocus, whose common ancestors appeared in the late Paleozoic period and were divided into two major evolutionary branches: the main dragon lower order and the lower scale dragon order.
Turtles and tortoises , Finnosaurus ( Plesiosaurs ) , and Ichthyosaurs are also clades of diphotancts , but their evolutionary locations are uncertain. Only the results of the latest DNA analysis from 2015 are quoted here, and plesiosaurs belong to the pantogy, belonging to the basic taxa of the main order, while ichthyosaurs are the basic taxa of the lower order of lepidoptera.
Systematic relationships in the reptile crown group
Lepidoptera includes the order Lepidoptera (snakes and lizards) and beaked lizards, and is the most prosperous reptile in modern times. The late Mesozoic ocean overlord, the Canglong Dragon, also belongs to the class of scaly dragons, and the Canglong dragon is actually a large marine lizard.
The main dragons are the main trunk of the evolution of the reptiles, and the surviving typical is the crocodile. It flourished in the Mesozoic Era, and both dinosaurs and pterosaurs belonged to this class. Dinosaurs are a combination of sauropods and ornithopods (duck-billed dragons, stegosaurs, horned dragons, etc.), and the sauropods are divided into sauropod suborders (diplodocus, brachiosaurus, and mammonii, etc.) and theropod suborders (allosaurs, tyrannosaurs, and dinosaurs, etc.). It is particularly noteworthy that birds are direct descendants of small theropod dinosaurs and therefore belong to the broad category of diphotos, and birds do have two pairs of temples on their heads.
In summary, the reptile crown group covers the ornithischia. The "extant reptiles + birds" form a monophyletic group, while the removal of the birds is only a parallel group.
Hoffman's dragon, the biggest dragon
The reptile population includes all animals with reptile features that have ever appeared on Earth, their latest common ancestor and all their descendants. This common ancestor can be traced back to the most primitive amniotic animals, the first animals on Earth to lay eggs.
The double-bow class is the crown group - true reptiles. Arch-deficients were all extinct before the age of the dinosaurs (late Triassic) and now have no living offspring, which we call parapigniths.
Zygoids are mammal-like reptiles, which are the direct ancestors of mammals. Mammals have only one pair of temples, and the upper and lower temporal foramen are combined into one and in the lower position, which is a key feature of the zygomatic arches. The evolution from zygomatic to mammalian is the same, and we are also a generalized zygomatic.
Systematic relationships between reptile populations
In summary, the total reptile group = crown group / true reptile + paraptile + zygomatic, and true reptiles contain birds, and zygotes contain mammals, so classical reptiles, birds, mammals together constitute a large monophyletic group - that is, all amniotic animals (mammals also have amniotic eggs in the early stages of embryonic development, but hatch in the womb, giving birth to fetuses instead of laying eggs).
From the perspective of phylogenetics, reptiles in the traditional sense are cohologies rather than monophyletics, both crown groups and total groups, so reptiles are an unscientific and unnatural concept. The most unscientific aspect of this concept is that it misrepresents the affinity between taxa, for example, the closest living relatives of crocodiles are birds, rather than turtles and lizards belonging to the same reptile.
According to textbooks, the common features of reptiles are: (1) the body surface is covered with dry keratinous scales and nails, (2) the body temperature is not constant (cold blood), (3) the heart has three chambers (the ventricular septum is incomplete), (4) lung breathing, (5) there are amniotic eggs (egg shells are hard), and reproductive development is free from the restriction of water.
Bay crocodile, the largest surviving reptile
In fact, none of these are really common features of reptiles. Lung respiration and amniotic eggs are common features of reptiles and birds and mammals. The presence of scales, three-chamber hearts and cold blood are only common features of some reptiles and fish or amphibians, while dinosaurs and pterosaurs are warm-blooded and four-cavity hearts like birds, some dinosaurs have feathers, and crocodiles are also four-cavity hearts.
Other taxa have key features that can be seen at a glance and are not confused with other animals, such as fetal and lactation in mammals, amphibian amphibians and metamorphosis of amphibians, why do reptiles not have such features? The true face of the reptile immediately surfaced. In fact, the traditional term reptile refers to all amniotic animals that are not birds or mammals, which is a typical concept of classified garbage cans.
Tyrannosaurus rex and triceratops
This classified trash can has brought us a lot of misleading, the most obvious of which is the understanding of dinosaurs. Initially, experts thought dinosaurs were cold-blooded and clumsy, on the grounds that dinosaurs were reptiles—amniotic animals that were not birds or beasts. However, dinosaurs are completely different from today's reptiles, crocodiles and lizards are "figure eight" legs, belly crawling animals, while dinosaurs and birds, mammals, legs are located directly below, the body can stand up.
In fact, dinosaurs were more agile than mammals of the same size. Tyrannosaurus rex and triceratops were larger than elephants, but they still maintained bent hind legs, proving that they could run like antelopes, while elephants had straight legs and could only pace slowly and could not make any jumps.
Many small theropod dinosaurs found in recent years have feathers, they have no wings, they can't fly, the main role of feathers is to keep warm, they are warm and bloody like birds. The picture below is a restored picture of Hu's Yaolong, like a primitive bird, if we lived in the Jurassic, would we still think that the boundary between dinosaurs and birds belonging to reptiles is insurmountable?
Hu's Yaolong, the smallest dinosaur
Scientists have also found that dinosaurs and pterosaurs have airbag structures, proving that they can breathe double-breath like birds. This is an extremely efficient way of breathing, with two oxygen inhalations per exhalation and inhale.
Therefore, the concept of reptiles is not an evolutionary branch, but more like an evolutionary stage. The combination of completely different animals such as dinosaurs, crocodiles, turtles, snakes and lizards to form a hodgepodge of reptiles really has no scientific basis and should be discarded.
As early as 1970, paleontologist Robert Barker proposed the idea of "galloping and hot-blooded dinosaurs", which promoted a revolutionary change in people's understanding of dinosaurs and reptile concepts. Soon after, some scholars proposed to abolish reptiles, merging the diphthongs that included birds with the lack of bows to form the lizards, and the combined bows that included mammals became the synaptic arches.
Phylogenetic diagram of vertebrates
The delay in reaching agreement among academics is due to the shortcomings of the systematic taxonomy itself. If reptiles are abandoned, what about amphibians and fishes that are also cohodied groups? Fortunately, the ancestors of amniotic amphibians have no other living offspring, only considering living animals, directly excluding the ectopic rodents from amphibians. Thus, amphibians refer only to the crown group, including the common ancestor of contemporary amphibians and all their descendants (synovial subclass).
Fish handling is more troublesome, tetrapod ancestors of the finfish still have other offspring alive, to accurately describe their systematic relationship, you must raise the classification level of fish. Amphibians, arches, and lizards are all orders, and tetrapods are superiors, and quadrupeds form an outline along with lungfish, and correspondingly juxtaposed coelacanths are also outlines. The meat fin fish was upgraded to the general order, and the spokefin fish (most of the existing teleost fish) became the general class, and together they formed the duroster fish superior. The classification hierarchy is completely inadequate.
In contrast, the classification of birds and mammals is greatly depressed. Birds are descendants of theropod suborder and can only become one family. Birds in the classical taxonomic system are a large taxonomic unit with 20 orders and more than 10,000 species, which is not counting prehistoric taxa.
Hapae, all birds are descendants of dinosaurs
Obviously, according to the systematic taxonomy, the level of taxa depends largely on the time of occurrence. Early emergences, even ghost taxa that have no living offspring, or remnant taxa with only a few descendants, can rise and become large taxa by the opening of the sister group alone. For example, there are only 6 species of lungfish and only two species of coelacanths left, but they are superior and outline-level units. In contrast, there are more than 10,000 species of birds but only one family.
The classification level in the Linnaean taxonomy was originally used to indicate the size of the taxonomic unit, which is the contradiction between the two. Perhaps Linnaeus's system can no longer adapt to the new situation of scientific development, so some scholars advocate the use of a non-hierarchical classification system and abolish all grades such as branches, orders, and classes.
Some scholars also argue that complex groups should be resolutely banned, but that merged groups can be retained to a certain extent. In this way, all the original programs can continue to be used. For small and medium-sized taxonomies below the order, it is relatively easy to maintain ideal monophyletic groups, but it is too difficult for large units above the order.
The Titalik fish, belonging to the salamander of hope, is the ancestor of quadrupeds
The biggest drawback of systematic taxonomy is probably that it cannot solve the problem of the breeding of common ancestors. Fortunately, it is difficult for us to find direct ancestor fossils, and most of the collateral branches found are found, and this problem has not bothered us for the time being. If one day we do find the group of labyrinths that evolved into amnioids, how do we determine its classification? Obviously, since its offspring are all amniotics, it must at least be an upper class, and we cannot give it a species, genus, family, order, it is only an upper class, and here Linnaeus's system completely collapses.
Given that the concept of reptiles misrepresents the kinship of dinosaurs, birds, crocodiles, and lizards, correction is probably imperative. But experts have not yet found a perfect solution to how to correct it, so the unscientific concept of reptile has remained in our textbooks for the time being.
Finally, we have to ask ourselves this question. Dinosaurs may have been the same thermostatic animals, equally able to stand. We have developed brains and high teeth chewing efficiency, and dinosaurs have their own advantages, its airbag system and hollow structure of bones make it grow larger, and the largest sauropod dinosaur weighs more than 4 times the largest land mammal ever built.
The Mesozoic era was the age of the main dragons
Dinosaurs appeared almost at the same time as mammals, yet they dominated the planet for 140 million years, and our ancestors could only circle around his feet, and without the meteorite 66 million years ago, mammals would not have seen any hope of taking over the world.
According to Darwin's post-evolutionary theory, all living things have a common ancestor, everyone has the same evolution time, and the differences in form and habits are only adaptations to different environments, so how can there be a distinction between low and high?
We humans are only 2 million years old, and how long can we survive after that? If one day, the end of the world comes, will the new rulers dismiss humans and mammals as inferior animals? I think it's time to abandon the stereotypical idea of inferior creatures.