What were the ancestors of the dinosaurs

The descendants of the dinosaurs

In ancient times crocodiles and dinosaurs had a common ancestor, the archosaurs. "It was only" 250 million years ago that these reptile groups separated in order to develop further in isolation from one another.

Nevertheless, descendants of the dinosaurs still live in the middle below - or above us. Because the birds are most likely descended directly from the dinosaurs.

The ancient bird Archeopteryx

This theory was triggered by the sensational discovery of the ancient bird Archeopteryx in 1861. This animal, which lived about 150 million years ago, looked like a mixture of a reptile and a bird.

On the one hand it had wings and feathers and a so-called wishbone like a bird, on the other hand it also had teeth, claws and a tail made of bones like a dinosaur. The resemblance to small predatory dinosaurs in particular cannot be overlooked. He still lacked the sternum, characteristic of birds, on which the flight muscles sit.

The Archeopteryx was therefore certainly not a good flyer and at most was capable of short gliding flights. But the similarity with modern birds is so great that the birds can be traced back to the dinosaurs.

Evidence of the theory of evolution?

The existence of such transitional forms or links has far-reaching consequences. They show directly how new animal species are created. This makes them a very important component of Darwin’s theory of evolution, according to which new species are formed through the gradual change in characteristics of existing species over many generations.

Two years after the appearance of Darwin's On the Origin of Species ("On the origin of species", 1859), the Archeopteryx was the first candidate for a link between two completely different species predicted by Darwin.

The great doubts that existed at the time about the theory of evolution were also carried over to the classification of Archeopteryx. Sir Richard Owen (1804-1892), leading anatomist of the 19th century and critic of Darwin's theses, considered the Archeopteryx to be a descendant of the pterosaurs and avoided any reference to the dinosaurs.

Today this question is hardly discussed any more. Most scientists are now of the opinion that the birds evolved from dinosaurs, namely from the group of coelurosaurs - these were lightly built, bird-like predatory dinosaurs.