What is the evolutionary history of mammals?
mammals are the latest evolutionary phase of one of the two main groups of amniot (non -lamps), synapsides. Nezrava synappers, often called Therapsids (although mammals are also technically therapy), have branched from another main Sauropsids (reptiles) in the Carbon period. The first known synappers was Archaeothyris , a small lizard creature that lived 320 million years ago. Like reptiles, synappers have evolved from carbon amphibians. Pelescosaurs are known to be the first large (1 meters to 3 meters or more) earthly amniot. They had large tail sails made of extended vertebral spikes, which are expected to be used to regulate body temperature and mating displays. Pelycosaurs, despite synappers, resembled reptiles superficially. This group was the most abundant land animal of an early Permian.
Most pelescosaurs to the end of The PERmian has died out or developed into other groups. One group, Sphenacodontids, has evolved into another main synapsis group, Therapsids. Therapsids once called "mammals similar to reptiles" look like Prot-Samals to an informal eye. This group developed in an early Permian and glued for about 150 million years, into an early chalk. This overlaps for about 100 million years with the age of dinosaurs. Before the dinosaurs appeared, they were the most numerous and successful earthly vertebrates during the late Permian therapy. Unfortunately, they were almost completely erased for the group during the Permian-Tiassic extinction, 251 million years ago.
In the gradual process, which lasted 70 million years, From Mid-Permian to Mid-Jurassic, one group Therapsids, Cynodonts, has evolved into a real mammal. Information about early mammals of the mesozoic era is rare because most of these creatures were smaller than rats and lived in contexts where fossilization was difficult. It is known that real mammals appeared before 125 million years, approximately 40 million years after "mammal" therapse -like therapy. One of the first mammals was Hadrocodium , although there is a debate about whether this kind was a real mammal. The first monotremes, placenta and marsupials - three main mammals types - have appeared for about the same time.
After the dinosaurs disappeared at the end of the chalk (65 million years ago) mammals quickly diversified and took over niches for large and medium -sized animals, which remained vacant extinct species. Today, mammals are dominant earthly vertebrates and reptiles are under their feet. Of course, on the contrary, the case was throughout the Mesozoic era.