Paleontologists recognize several mass extinctions in the past 500 million years, which occurred in Ordovician, Devonian, Paleozoic, Mesozoic, Triassic, and Cretaceous Period, respectively. The most recent mass extinction was at the end of Cretaceous Period, and resulted in the loss of 76% of all species, most notably the dinosaurs.
- paleontologist [ˌpæliɔnˈtɔlədʒist] n.古生物学者
- mass extinction [mʌs - iksˈtiŋkʃən] n.大量消亡
- Ordovician [ˌɔ:dəˈviʃən] n.奥陶纪
- Devonian [deˈvəuniən] n.泥盆纪
- Paleozoic [pæliəˈzəuik] n.古生代
- Mesozoic [ˌmesəuˈzəuik] n.中生代
- Triassic [traiˈæsik] n.三叠纪
- Cretaceous [kriˈteisiəs] n. 白垩纪
- respectively [risˈpektivli] adv.分别地
- species [ˈspi:ʃi:z] n.物种
- dinosaur [ˈdainəsɔ:] n.恐龙
