Mesozoic Earth: Five Ways the Dinosaur World Differed From Our Own
From the Triassic period, when dinosaurs first appeared over 235 million years ago, until the asteroid impact 66 million years ago, flowering plants were absent; the landscape was dominated by ginkgo trees, horsetails, and the now-extinct bennettitales. Large dinosaurs played a crucial role in maintaining open forests by consuming vegetation. Around 125 million years ago, flowering plants began to emerge, with palms showing up by 75 million years ago. The Mesozoic era, lasting from 252 to 66 million years ago, was characterized by a warm climate and included the Cretaceous, Jurassic, and Triassic periods. Most of the land was part of the supercontinent Pangaea, which fragmented by 170 million years ago. Mesozoic seas were home to ammonites, ichthyosaurs, and plesiosaurs, while early mammals like Kayentatherium coexisted with dinosaurs.
Key facts
- Dinosaurs originated more than 235 million years ago; an asteroid strike 66 million years ago left beaked birds as the only surviving dinosaurs.
- Flowering plants did not exist when the earliest dinosaurs appeared in the Triassic; ginkgo trees, horsetails and bennettitales dominated instead.
- Flowering plants became common around 125 million years ago in the early Cretaceous; by 75 million years ago palms grew alongside leafy plants with large fruit.
- The Triassic followed Earth's biggest mass extinction, when volcanic eruptions in what is now Siberia released carbon dioxide and methane, raising average global temperature to about 89 degrees Fahrenheit, compared with about 59 degrees today.
- The Mesozoic spanned 66 million to 252 million years ago: Cretaceous 66–145 million, Jurassic 145–201 million, Triassic 201–252 million.
- Most landmass was joined in the supercontinent Pangaea, which plate tectonics broke apart; by around 170 million years ago Eurasia was separated from other landmasses.
- Mesozoic oceans contained ammonites with coiled shells up to eight feet in diameter, crinoids, ichthyosaurs, plesiosaurs, pliosaurs and mosasaurs.
- Kayentatherium, a mammaliaform from 185 million years ago, could have litters of 38 babies; multituberculates by 170 million years ago had smaller litters and fed their young milk.
Entities
Artists
- Riley Black
- Roger Harris
- Heather Kyoht Luterman
- Andrey Atuchin
- Michael Skrepnick
- Christopher R. Scotese
- Christian Vérard
- Landon Burgener
- Reece P. Elling
- Ádám T. Kocsis
Institutions
- Smithsonian magazine
- Science Photo Library
- Getty Images
- Wikimedia Commons
Locations
- Siberia
- Russia
- China
- North America
- South America
- Africa
- Eurasia
- Australia
- Antarctica
- Pangaea
- Laurasia
- Gondwana
- Shishugou Formation