Dinosaurs Still Roam the Earth, But Not in the Way You Think

Paleontologists have extensively studied dinosaurs, but none of their discoveries have revealed any living creatures. However, a connection exists between dinosaurs and their bird-like descendants. The theory that a giant asteroid collided with Earth, causing the extinction of dinosaurs 66 million years ago, is supported by various scientific findings. Despite the extinction of dinosaurs, some of their characteristics, such as feathers and high body temperatures, are seen in modern birds.

Key Takeaways:

• The asteroid impact theory is supported by the discovery of iridium in a layer of clay between rocks from the Cretaceous and Paleogene periods, which dates back to the time of dinosaur extinction.
• The asteroid collision was so powerful that it sent trillions of tons of dust and molten rock into the sky, causing massive wildfires and a prolonged "impact winter" that led to the extinction of dinosaurs.
• Small animals like mammals, lizards, and turtles were able to adapt to the changing environment, and birds, the only remaining dinosaurs, were able to survive and eventually evolve into the birds alive today.
• The discovery of feathered dinosaur fossils and the similarities in the skeletons of modern birds and fossilized dinosaurs have confirmed the connection between them.
• The earliest known bird, Archaeopteryx, shared many reptilian traits with dinosaurs and had a long tail, sharp teeth, and hands with three fingers.
• The S-shaped neck, hollow bones, and extremely flexible wrist of Archaeopteryx are also seen in modern birds, further supporting the link between dinosaurs and birds.
• Most paleontologists agree that many if not all dinosaurs maintained constant high body temperatures, just like birds and mammals, due to the presence of feathers.
• Some bird-like dinosaurs, including close relatives of Deinonychus, were covered in feathers, just like modern birds.

Statistics:

• The claimed size of the asteroid is approximately 6 miles (10 kilometers) in diameter.
• The asteroid collision is believed to have triggered the extinction of approximately 75% of all species on Earth.
• The layer of clay with iridium is located in the Apennine mountains in Italy and dates back to the time of dinosaur extinction.
• The asteroid crater, buried under the sea floor off the Yucatan Peninsula of Mexico, is estimated to be about 180 kilometers (110 miles) in diameter.
• Feathers are found in many bird-like dinosaur fossils, including those of Deinonychus and its close relatives.

Sources:

• The Conversation -- USA -- By Hans Sues, Senior Research Geologist and Curator of Vertebrate Paleontology, Smithsonian Institution
• Wikipedia - Ankylosaurus
• Wikipedia - Archaeopteryx
• Wikipedia - Deinonychus
• Wikipedia - Iridium
• Science Photo Library - Deinonychus
• Science Photo Library - Archaeopteryx