Which of the following are considered to be a direct ancestor of birds? Choose all that are correct: Enantiornithes Hesperornithes None of the above Ichthyornis Bigfoot
The Correct Answer and Explanation is:
The correct answers are Enantiornithes, Hesperornithes, and Ichthyornis.
Explanation:
Birds are directly descended from a group of theropod dinosaurs, specifically from a lineage that included some species of primitive flying dinosaurs. Over time, these creatures evolved into modern birds. Here’s a breakdown of the options:
- Enantiornithes: This is an extinct group of early birds that lived during the Mesozoic era, specifically in the Cretaceous period. Enantiornithes are considered one of the direct ancestors of modern birds. Their fossilized remains have been found in various parts of the world, and they exhibit characteristics that are similar to both dinosaurs and modern birds. They are often called “opposite birds” due to the unique structure of their shoulder joint, which was different from that of modern birds.
- Hesperornithes: Hesperornithes is another extinct group of early birds, also from the Mesozoic era, particularly the Late Cretaceous. These birds were aquatic and had characteristics that suggest a transitional form between dinosaurs and modern birds. Their body structure was somewhat similar to that of modern aquatic birds, and they are thought to be part of the evolutionary chain leading to modern birds.
- Ichthyornis: This genus belongs to an early group of birds that lived during the Late Cretaceous. Ichthyornis is considered an important part of the bird evolutionary tree. Its fossil features a mix of both avian and dinosaur traits. Ichthyornis had teeth (which are absent in modern birds) and a more primitive skeletal structure, but it also exhibited features like a keeled sternum that are found in modern birds.
- Bigfoot: This is a mythical creature and has no scientific evidence or relationship to the evolution of birds. It is not considered an ancestor of birds or any other species.
Therefore, Enantiornithes, Hesperornithes, and Ichthyornis are the direct ancestors of birds, while Bigfoot is not.
