How did mammals evolve? What did the early mammals evolve gradually?

Early mammals gradually evolved the placenta because of the use of some of the virus's genes, and its most prominent feature is that viviparity and its young are fed by the mother's milk and have a relatively developed brain, so they can produce more complex behaviors than other animals.

Mammals are the most morphologically structured and physiologically functional animals in the animal world, and they all have fur to keep their body temperature constant. There are more than 4,000 species of mammals in the world, and although they are all highly evolved, they still have a lot in common, and almost all mammals are warm-blooded.

Although the nests of mammals are not as delicate as those of birds, they are varied and varied, and some marine animals, such as fur seals and seals, generally do not inhabit the water, but build their nests on the shore.

Early mammalian evolution

No one knows what the earliest mammals were like. But scientists have found fossils of a weasel-like paleontocrat in the Wales and Bristol regions of England, and the burrowing animal known as the Morgan-tooth is likely an early mammalian species.

These early mammals are said to be smaller, insect-feeding, nocturnal, hairy, and warm-blooded. In fact, this feature of warm blood is the first characteristic of the Ichroporeidae reptiles, who are probably the ancestors of mammals, and have witnessed the rise and fall of the entire Jurassic period along with the vast majority of dinosaurs, and even almost entered the Cretaceous period.

These early mammals were very close to the monotremes of the time and probably maintained an oviparous habit. Marsupial mammals and placental mammals as we know them evolved about 70 million years later.

Throughout the Jurassic period, mammals were short in size and mostly still preferred to be nocturnal, reminiscent of them walking under the feet of giant dinosaurs.

1.Mammals, like birds, are all reptiles that evolved. Mammals are a class of the subphylum Blind Vertebrates, commonly known as mammals.

Mammals are found all over the world and live a variety of lifestyles on land, underground, in the water and in the air. There are three types of nutrition: herbivorous, meat-fed and omnivorous;

2.The earliest mammalian scattered menhir was the Wu giant head found in China. Every tooth in reptiles is the same, while mammalian teeth are divided into different morphologies depending on where they are located in the jaw.

In the animal kingdom, only mammals have three bones in their ears. They evolved from the two jaws of reptiles;

3.Mammalian evolution is done through movement and food chain alterations. The five-toed limbs of primitive mammals, which are suitable for walking on the ground, have evolved into many specialized types as they adapt to different lifestyles, and primitive mammals are mainly omnivores that feed on insects.

Later, due to adaptation to different lifestyles, they evolved into: omnivores, feeding on animals and plants; Herbivores feed on plants; Carnivores feed on animals.

At the end of the Carboniferous period, a group of mammal-like reptiles developed in the reptile trunk cuposaurus, that is, the Coilosaurus, which evolved into the Oriodonda, and a branch of the Orrodontosaurus evolved into the ancestor of mammals. The earliest mammals appeared around the end of the Triassic to the beginning of the Jurassic. In biological evolution, the origin of mammals is still relatively less controversial.

Primitive reptiles.

A mammal is a homeothermic, vertebrate animal with hair, mostly viviparous, and feeds its offspring through the mammary glands. Mammals are the most advanced stage in the history of animal development, and they are also the most closely related to humans.

The largest mammal: the blue whale.

The largest land mammal: the African elephant.

Tallest mammal: giraffe.

The fastest mammal: the cheetah.

The most smelly mammal: the American skunk.

What animals did primitive mammals evolve from?

a primitive fishes b primitive amphibians c primitive reptiles d primitive birds.

Take the platypus as an example, the monopore mammal in Australia, the most peculiar is the platypus. The so-called monotremes refer to an animal that is between reptiles and mammals. Although it is more advanced than reptiles, it has not yet evolved into a mammal.

The similarity between the two is that they both breathe with their lungs, have hair on their bodies, and are hot-blooded; Monopore, on the other hand, reproduce by laying eggs, thus retaining important characteristics of reptiles. Although it is listed as a mammal, it does not have the complete characteristics of mammals. It is the most primitive and lowest mammal, and is called "protozoars" or monopore oviparous mammals in animal taxonomy.

A group of ancient reptiles, the therodonts, gradually evolved into mammals.