Origin of birds
The Earth is home to over 10,000 species of birds. To understand their origins, researchers have explored the fossil record and traced their evolution over time. In 1861, the first intermediate organism connecting reptiles and birds was discovered in Germany- Archaeopteryx. It had feathered wings and a feathered tail like modern birds, but other features such as a long boney tail and a toothed beak more commonly associated with reptilians. While some believed that Archaeopteryx may have evolved from pterosaurs, this idea was eventually discounted due to the lack of similarities in wing structure. In the mid-20th century, the idea that birds evolved from dinosaurs began to gain traction, due to John Ostrom’s proposition that some dinosaurs were small and agile. By the 1980s, there was a consensus that birds evolved from therapods, a group of dinosaurs characterized by hollow bones and three-toed limbs. Although it was originally believed that feathers were evolved for flight, the discovery of wingless, feathered therapods showed that feathers pre-date flight, and must have evolved for other purposes, such as insulation or mating displays. Over time, true birds evolved, and a small group of them survived the KT extinction; these diversified into the birds we see today.
Following the evolution of birds through geologic time is a fascinating experience. New discoveries are being made constantly, and as we explore more of the fossil record, we will likely learn much more about the evolution of not only birds, but other animals as well. Examining the evolution of birds on a long time scale like this gives me much more of an appreciation for the small changes we learned about taking place in the Galapagos and elsewhere around the world; given enough time, small adaptations can lead to a whole new group of organisms.
Following the evolution of birds through geologic time is a fascinating experience. New discoveries are being made constantly, and as we explore more of the fossil record, we will likely learn much more about the evolution of not only birds, but other animals as well. Examining the evolution of birds on a long time scale like this gives me much more of an appreciation for the small changes we learned about taking place in the Galapagos and elsewhere around the world; given enough time, small adaptations can lead to a whole new group of organisms.