Jurassic period: 56 million years of giants
From 201 to 145 million years ago giant sauropods, fierce predators and the first birds ruled warm Earth.
Sauropod giants and armored herbivores
The Jurassic lasted from 201 to 145 million years ago, about 56 million years. Carbon dioxide was 4 times modern levels, global temperature averaged 16 to 20 degrees, and sea level stood 100 meters higher than today.
Sauropods like 35-meter Argentinosaurus weighed about 70 tonnes, while 25-meter Brachiosaurus browsed 9 meters high. Stegosaurus reached 9 meters with 1-meter plates, and 9-meter Allosaurus hunted in packs across floodplains.
First birds and gentle ending
Around 150 million years ago Archaeopteryx combined feathers, wings of 50 centimeters and teeth. Small feathered dinosaurs under 2 meters climbed trees in warm conifer forests where insects and mammals diversified rapidly.
The period ended near 145 million years ago with only minor extinctions losing about 20 percent of marine genera. Warm shallow seas, coral reefs and fern prairies continued into the Cretaceous, carrying giants to even larger sizes.
- Lasted 56 million years, 201 to 145 million years ago.
- Argentinosaurus 35 meters and 70 tonnes.
- Allosaurus and Stegosaurus 9 meters.
- Archaeopteryx about 150 million years ago.
- Ending lost only 20 percent of genera.