Question 1

How do you say Mesozoic?

Accepted Answer

Mesozoic is pronounced mez-oh-ZOH-ik. Break it into four parts: MEZ, then OH, then ZOH, then IK, with the strongest emphasis on the third syllable ZOH. Say it fast: mez-oh-ZOH-ik. Once you get the ZOH part loud and clear, the whole word flows naturally.

Question 2

What does Mesozoic mean?

Accepted Answer

Mesozoic comes from two Greek words. 'Mesos' means middle, and 'zoion' means animal or living being. So Mesozoic literally means the era of middle animal life. It sits between the older Paleozoic era and the newer Cenozoic era, which is why geologists called it the middle one. British geologist John Phillips came up with the name back in 1841.

Question 3

How long did the Mesozoic Era last?

Accepted Answer

The Mesozoic Era lasted approximately 186 million years, from about 252 million years ago to 66 million years ago. To put that in perspective, the entire time since the dinosaurs went extinct is only about 66 million years, so the Mesozoic was nearly three times longer than that. It is divided into three periods: the Triassic, the Jurassic, and the Cretaceous.

Question 4

What dinosaurs lived in the Mesozoic?

Accepted Answer

All non-avian dinosaurs lived during the Mesozoic Era, since they evolved in the Triassic Period and went extinct at the end of the Cretaceous Period. This includes iconic species like Stegosaurus and Brachiosaurus from the Jurassic, and Triceratops and Tyrannosaurus rex from the Cretaceous. Interestingly, T. rex and Stegosaurus never met because about 80 million years separated them, even though both lived in the Mesozoic.

Question 5

What ended the Mesozoic Era?

Accepted Answer

The Mesozoic Era ended approximately 66 million years ago when a massive asteroid roughly 10 to 15 kilometers wide hit Earth near what is now Mexico's Yucatan Peninsula. The impact created the Chicxulub crater and triggered wildfires, tsunamis, and a long period of darkness as debris blocked sunlight. About 75 percent of all species on Earth went extinct, including all non-avian dinosaurs. This event is called the Cretaceous-Paleogene extinction event.

Question 6

Was the Mesozoic hotter than today?

Accepted Answer

Yes, the Mesozoic was significantly warmer than our modern world. Global average temperatures were estimated to be 4 to 10 degrees Celsius higher, and there were no polar ice caps at all during most of this era. Forests grew in Antarctica, and crocodile relatives lived in the Arctic. The high levels of carbon dioxide in the atmosphere acted like a greenhouse blanket trapping heat around the planet.

Question 7

What came before and after the Mesozoic?

Accepted Answer

Before the Mesozoic came the Paleozoic Era, which ended with the catastrophic Permian mass extinction about 252 million years ago that wiped out up to 96 percent of marine species. After the Mesozoic came the Cenozoic Era, which began 66 million years ago and continues today. The Cenozoic is sometimes called the Age of Mammals because mammals diversified rapidly after the dinosaurs disappeared.

Question 8

Did humans exist in the Mesozoic?

Accepted Answer

No, humans did not exist during the Mesozoic Era. Modern humans, Homo sapiens, only evolved about 300,000 years ago, while the Mesozoic ended 66 million years ago. That means the gap between us and the end of the Mesozoic is more than 200 times longer than the entire history of our species. Our earliest mammal ancestors did live during the Mesozoic, but they were tiny shrew-like creatures, nothing like us.

Question 9

What did the Earth look like during the Mesozoic?

Accepted Answer

Early in the Mesozoic, all of Earth's continents were joined together into one giant supercontinent called Pangaea, so you could theoretically walk from what is now North America to Africa without crossing an ocean. Over the millions of years of the Mesozoic, Pangaea slowly split apart, the Atlantic Ocean was born, and the continents drifted toward their modern positions. Shallow warm seas flooded large areas of the continents, and the world had no permanent ice anywhere.

Question 10

Were there any mammals in the Mesozoic?

Accepted Answer

Yes, mammals evolved during the Triassic Period, early in the Mesozoic, around 225 million years ago. However, Mesozoic mammals were mostly small, nocturnal, and insect-eating creatures, not the large diverse mammals we know today. They lived in the shadow of dinosaurs for over 150 million years, never growing much larger than a badger. It was only after the dinosaurs went extinct at the end of the Mesozoic that mammals had the chance to diversify into the enormous variety of forms we see today.

Question 11

What plants grew in the Mesozoic?

Accepted Answer

The Mesozoic was dominated by gymnosperms, plants that produce seeds but not flowers. These included cycads, ginkgo trees, and tall araucarian conifers similar to today's monkey puzzle trees. Flowering plants only evolved and started spreading during the Cretaceous Period, the last chapter of the Mesozoic. There was no grass at all for most of the Mesozoic, so giant plant-eating dinosaurs were eating ferns, cycad fronds, and conifer needles instead.

Question 12

What is the difference between Mesozoic and Jurassic?

Accepted Answer

The Mesozoic is the entire era, while the Jurassic is just one of three periods within it. Think of the Mesozoic as a book and the Jurassic as one of its three chapters. The Triassic Period came first (252 to 201 million years ago), then the Jurassic (201 to 145 million years ago), then the Cretaceous (145 to 66 million years ago). The Jurassic Park movies are named after just one part of the much longer Mesozoic story.

Question 13

Who came up with the word Mesozoic?

Accepted Answer

British geologist John Phillips coined the term Mesozoic in 1841. Phillips was studying fossil records and noticed that different layers of rock contained distinctly different groups of animals, separated by what appeared to be mass extinction events. He proposed three eras of complex life and named them using Greek roots: Paleozoic for the ancient one, Mesozoic for the middle one, and Cenozoic for the recent one. His naming system is still used by scientists around the world today.

Mesozoic Pronunciation

What does Mesozoic mean?

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