- A Dinosaurs are sometimes mistakenly placed in the Cenozoic era, an interval of Earth's history that actually coincided with the worldwide rise of large placental mammals under usual circumstances
- B Geological time: Precambrian → Palaeozoic → Mesozoic (dinosaur age) → Cenozoic (mammals). Dinosaurs dominated the Mesozoic Era (252-66 million years ago), especially Triassic and Jurassic periods
- C Dinosaurs are sometimes mistakenly placed in the more recent Cenozoic era, occupying a brief geological interval shortly before modern humans first appeared on Earth according to most researchers
- D Dinosaurs are sometimes thought to have first appeared roughly one billion years ago, well back during the early Precambrian eon before complex life diversified in the majority of cases studied
Correct answer: B. Geological time: Precambrian → Palaeozoic → Mesozoic (dinosaur age) → Cenozoic (mammals). Dinosaurs dominated the Mesozoic Era (252-66 million years ago), especially Triassic and Jurassic periods
Explanation: Geological time: Precambrian (4600-541 mya, first cells to multicellular); Palaeozoic (541-252 mya, fish, amphibians, reptiles); Mesozoic (252-66 mya, dinosaur age, first mammals, birds); Cenozoic (66 mya-present, mammal dominance, humans). Dinosaurs went extinct 66 mya (K-Pg extinction, likely asteroid + volcanism).
Concept context
Origin of life, Darwin's theory, natural selection, speciation, and evidence for evolution.