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Kevin C. HartzogGeologic Time Scales
Mesozoic Era
Dating from 245-65mya, the Mesozoic (Middle Animals) Era, the age of the dinosaurs, mark the beginning of land animals and plants. During this Era, Gymnosperms first evolved, invading deep into new territory away from shores where water was plentiful. As these new plants moved inland, animals soon followed. The dinosaurs evolved, flourished in every habitat on land, then re-invaded the oceans. The Mesozoic ended as the dominant dinosaurs died after a meteor struck the Earth, changing the environment. The first mammals and birds appeared during the Mesozoic Era, surviving in specialized niches as the dinosaur continued its control on most of the available niches.