Introduction
Have you ever really looked at a bird’s feet? Most birds have clawed toes and scales covering their feet. Birds also lay eggs in nests. These three traits are found in reptiles as well. However, birds have many other traits, such as feathers and warm-bloodedness,
that are not found in modern reptiles. One of the most famous fossils ever found isArchaeopteryx, a small animal with clawed toes, scaly legs, teeth, and feathered wings.Archaeopteryx was found in rocks dating from the Jurassic Period, 150 million years ago. Many scientists classify Archaeopteryx as a bird. Other scientists point out that, if you took away the feathers, this fossil would look just like Deinonychus, a small theropod dinosaur. Scientists agree that Archaeopteryx wasn’t able to fly, partly because it had a flat sternum (breastbone). Birds have a keeled sternum to which flight muscles are attached. Yet Archaeopteryx clearly had feathers. Was this fossil a dinosaur or a bird? This is only one of the many questions paleontologists struggle with when they study the evolution of birds.
One of the first people to make a connection between dinosaurs and birds was Thomas Huxley, a contemporary of Charles Darwin in the 1800s. In 1916, a Danish doctor named Heilmann wrote a book titled The Origin of Birds, in which he listed the similarities between the skeletons of theropod dinosaurs and modern birds. Later fossil discoveries made these similarities more striking. In the 1960s, an American named John Ostrom found 22 features in theropods and birds that could not be found in any other animal groups
Task
Your job in this WebQuest is to form an opinion as to the origins of birds. You will have to find out what evidence supports the theory that birds descended from theropod dinosaurs. You will have to identify the similarities among birds and other groups of animals. You will also learn about new fossils that provide additional information about the evolution of birds. You will prepare a table in which you compare and contrast several fossils that may, or may not, be links in the evolutionary history of birds. Finally, you will use the information from your Internet research and the table you have prepared to answer the following question: are birds really dinosaurs?
Process
Now that you have completed your research on the Internet, prepare a table that lists the bird and/or birdlike dinosaur fossils that provide some evidence of the origins of birds. In the left column, write the genus names of the fossils you have studied. At the top of the rows, write in the age of the fossil, where it was found, and why it is important to the study of bird evolution. The table is started for you below.
| Name of Fossil | Age (millions of years) |
Location | Important Facts |
| Longisquama | 220 | Kyrgyzstan | was an archosaur, a type of reptile; was neither a bird nor a dinosaur; had complex set of feathers and a furcula (wishbone) - both bird characteristics |
| Archaeopteryx | 150 | Germany | has clawed toes, scaly feet, wings, feathers (bird characteristics); has teeth, flat sternum (reptile characteristics) |
Conclusion
In the process of completing this WebQuest, you’ve become informed about the evidence linking birds with dinosaurs, and about new fossil discoveries that challenge the theory that birds evolved from theropods. You have developed critical thinking skills and you have explored the many different facts that relate to the question of the origins of birds. You have read information to complete a table about bird and birdlike fossils, and formed an educated opinion as to the origins of birds. Are birds really dinosaurs?