The Mesozoic Era is best known as the age of the dinosaurs. These large reptiles dominated the land and seas of the Earth during this era. Dinosaurs filled all the niches that are currently filled by mammals today. There were plant eating, meat eating, endothermic, bipedal, and quadrupedal dinosaurs. Dinosaur bones had canals, which indicated that they were active creatures.
Climate alternated between cool, warm, and tropical seasons, but overall the planet was much warmer than today. The Mesozoic Era’s atmosphere had more oxygen than the atmosphere today.
The Mesozoic era was known as the age of the reptiles. Compared to their amphibian ancestors, reptiles were able to move on to land because they had a thick skin which kept much of the body moisture and amniotic eggs which ensured successful reproduction. Mammals would appear near the end of the Triassic.