BIRDS EVOLUTION

Evolution of modern birds. there are 30 living birds order, but in this cladogram, it only shows 9 types important birds order. The earliest known birds, Archaeopteryx, lived in the upper Jurassic period about 147 million years ago. Archaeopteryx uniquely shares many specialized aspects of its skeleton with the smaller theropod dinosaurs and is considered to have evolved within the theropod lineage. Evolution of modern bird orders occured rapidly during the Cretaceous and early Tertiary periods.