Origin of Angiosperms and Their Diversification in the Cretaceous

• 作者: Xin Wang
• 来源期刊: 地质学期刊(英文)
• 学科: 医学
• 关键词: Jurassic TRIASSIC ANGIOSPERMS ORIGIN Evolution FOSSILS UNIFYING Theory
• 年，卷（期）: 2019,（10）
• 页码范围: 577-580
• 页数: 4页
• 分类号: R73

摘要

The dominating hypothesis stated that angiosperms originated in the Early Cretaceous, there were no pre-Cretaceous angiosperms, and carpels (the basic units of gynoecium) were derived from former megasporophylls bearing ovules/seeds along their margins through longitudinally folding and enrolling. However, there are increasing evidences of pre-Cretaceous angiosperms, the assumed megasporophyll actually does not exist, and the Cretaceous-only history of angiosperms appears much shorter than suggested by molecular clocks. Here I will integrate new knowledge of living and fossil plants to give a plausible explanation for the origin and early evolution of angiosperms. Several lines of evidence indicate that the ancestor of angiosperms may well have been present in the Triassic. The former gap between angiosperms and gymnosperms is artificial. Some Triassic fossils playing a role intermediate between angiosperms and gymnosperms seem to favor the Unifying Theory.