Dino discoveries add up

This exercise is a part of Educator Guide: What Makes a Dinosaur? / View Guide

1. How common were feathers among dinosaurs can you find a relevant article? What are the main points of the article?

Possible student response: The Science News article “Feathered dinosaurs may have been the rule, not the exception,” published 8/23/2014, describes a newly discovered plant-eating dinosaur that had both scales and feathered plumes. It was already known that birds evolved from dinosaurs, and that closely related dinosaurs had feathers. However, this new dinosaur was far from the lineage that gave rise to birds, yet structures on this fossil reveal that it was perhaps covered with at least three different types of feathers. This discovery suggests that most or all dinosaurs may have been covered with feathers. Scientists speculate that the feathers could have helped the dinosaurs keep warm and/or attract mates.

2. Can you find an article that summarizes a number of other recent dinosaur discoveries? Describe the dinosaurs mentioned in the article.

Possible student response: The Science News article “Year in review: Roster of dinosaurs expands,” published 12/27/2014, discusses several recent dinosaur discoveries. Dreadnoughtus schrani, a newly discovered sauropod in what is now Argentina, weighed more than seven times a T. rex. A T. rex–like dinosaur called Torvosaurus gurneyi was discovered to have lived in what is now Europe during the late Jurassic Period. Scientists proposed that dinosaur physiology was somewhere between warm-blooded birds and cold-blooded reptiles, and that some were able to settle in chillier climates near what is now the Arctic. Spinosaurus, a sail-backed theropod, may have been equally at home in or out of the water.

3. Can you find a recent article about evidence for what caused the extinction of the dinosaurs? What hypotheses are explained in the article?

Possible student response: The Science News article “Devastation detectives try to solve dinosaur disappearance,” published 2/4/2017, explores evidence for two leading theories about the extinction. The Cretaceous-Tertiary, or K-T, extinction wiped out most of the dinosaurs and many other species approximately 66 million years ago. One theory is based on extensive evidence that an asteroid (or possibly a comet) crashed near what is now Chicxulub, Mexico. That collision created a 180-kilometer-wide crater, blasting earth into the upper atmosphere and blocking sunlight to create a worldwide winter for a year or so. The impact also triggered tsunamis and showers of hot debris. A competing theory is based on evidence for massive Deccan volcano eruptions in what is now India that occurred at approximately the same time as the extinction event. The eruptions released massive amounts of carbon dioxide and caused relatively rapid global warming and ocean acidification. While it could be a coincidence that the asteroid impact and the eruptions happened around the same time, it is also possible that the asteroid impact triggered or exacerbated the Deccan volcanic eruptions.