Why haven t vertebrates evolved in nature that have both wings and forelimbs?

Ancient pterosaurs and modern bats were vertebrates with wings and forelimbs, but their wings and forelimbs were one. The absence of vertebrates in nature where wings and forelimbs exist separately at the same time is due to the evolution of vertebrates**.

Earth's terrestrial vertebrates have a common evolution**, which is an evolution of a branch of marine flesh-finned animals. Some species of marine flesh-finned animals have a spine from head to tail tip, with a skeletal structure in the four fleshy fins, which breathe with lungs and are able to briefly move and forage on land, and over time some of them have fully adapted to life on land and become the co-evolutionary ancestors of terrestrial vertebrates.

Therefore, no matter what form of limbs of terrestrial vertebrates is, there can only be 4 in number, two wings and two legs, four legs, two legs and two arms, which can correspond to the ancestors of flesh-finned animals in terms of quantity. A few species, such as snakes, eventually evolved to crawl on the ground without limbs and on muscles and scales, due to the expression of a gene in the snake gene called ZRS that regulates the function of the genome, and when this gene is implanted into the mouse genome, the hind limbs of the mouse show a shortening change.

The production of wings is probably due to some arboreal animals or animals with thick and long feathers on their forelimbs, which can glide in the air for a short time, which is conducive to them to avoid the hunt of natural enemies, and the competition for survival makes their forelimbs gradually deformed, and the forelimbs gradually become flattened and the area increases, supplemented by flat feathers so that the wings can hold more air after opening, and the rapid movement can produce the lift force that supports the weight and becomes the wings.

Dissecting the forelimbs of birds or bats shows that the main long bones and joints of their forelimbs resemble their mammalian counterparts in number and type, while the ends of the limbs have evolved quite differently, and the wing bones of birds have evolved into a vacuum due to the weight of the bones dragging down flight. Only a few vertebrates still crawl on land due to the need for foraging and other needs, and some bones at the end of their limbs have evolved into a claw-like structure, and the forelimbs and wings are two in one, so there are no vertebrates with independent wings and forelimbs, and a total of 6 limbs.

It is difficult to see the connection between the history of the earth and the living organisms of a certain animal in isolation, and the evolution of vertebrates needs to be viewed from the whole evolutionary process, and the skeletal structure of the evolutionary ancestors of vertebrates determines the number of vertebrate limbs.

Because the appearance of each animal has a certain principle, it is not how to develop as it wants, if this is the case, it will disrupt the order of the animal kingdom.

Invertebrate.

of the wingless form.

Then I think it's some invertebrate bugs, like maggots, or some mollusks, like caterpillars.

Something like that. Insects are of great variety and morphology, belonging to the arthropods of invertebrates, and are the most abundant animal group on the planet, with a wide variety of species (including bacteria, fungi.

germs) account for more than 50%, and their traces can be found in almost every corner of the world. Until the beginning of the 21st century, there were more than 1 million species of insects known to humans, but there are still many species yet to be discovered. Insects are the most diverse and abundant in the animal kingdom and have a significant impact on agricultural production and human health.

The most common are locusts.

Butterflies, bees, dragonflies, flies.

Grasshoppers, cockroaches, etc. Not only are there many species of insects, but the number of individuals of the same species is also staggering.

The distribution of insects is so wide that no other class of animals can compare with it, and it is almost all over the earth. There are different types. Most insects can be used as specimens, and they are a good biological resource that humans can use.

The body of an insect is divided into three parts: head, thorax, and abdomen. Adults usually have 2 pairs of wings and 6 legs, the wings and feet are located in the thorax, and the body is composed of a series of body segments, which are further assembled into 3 segments (head, thorax and abdomen). A pair of antennae are head-born, and the bones are wrapped around the body; The form of life is varied, and it is spread all over the world.

It is one of the most diverse arthropods.

Insects are the most abundant animals in the world, with more than 1 million species discovered, more than all other animal species combined.

Insects are structurally different from vertebrates, their bodies are not supported by an endoskeleton and are covered with chitin.

English chitin). This shell is divided into sections to facilitate movement, like a knight's armor.

Insects play an important role in the biosphere. Insect flowers need the help of insects in order to spread pollen.

And honey collected by bees is also one of people's favorite foods. in Africa, Southeast Asia.

and in some parts of South America, insects themselves are food for the locals.

But insects can also pose a threat to humans, such as locusts and termites. And some insects, such as mosquitoes, are also transmitters of diseases.

Some insects are capable of harming humans through venom or bites. For example, wasps.

A sting needle will be used to inject venom into the intruder.

Invertebrates evolve into vertebrates as a result of natural selection and genetic variation. Because vertebrates are more advanced, they are easy to adapt to the environment. Most vertebrates evolved from invertebrates.

Evolved into vertebrates. Zoologists have found a similar trend in some of the higher invertebrates in recent studies.

It could evolve into vertebrates, it could evolve into amphibians, it could evolve into others, and to be sure, it would evolve into species fit for survival.

1. In invertebrates, only insects have wings, and only insects can fly 2. The body temperature of non-homeothermic animals is mainly controlled by the following two:

1.Heat generated by metabolism.

2.Maintain a balance between heat retention and heat loss (e.g. through diet).

The evolutionary process of animals is: primitive single-celled animals Invertebrates Vertebrates And the evolutionary process of vertebrates is primitive fishes Primitive amphibians Primitive reptiles Primitive birds, mammals Animals are divided into vertebrates and invertebrates according to whether the whole body is composed of vertebral bones or not Among them, insects in invertebrates have wings and are able to fly; Birds among vertebrates have structural characteristics such as forelimbs turning into wings, streamlined bodies, double breathing, body surface covered with feathers, some bones are hollow, some bones are healed, and the rectum is very short. Although the mode of reproduction of mammals is viviparous and lactating, its structural characteristics determine that it is a battalion flight life

So the answer is: insects; Bird; Bats