Abstract

JARAMILLO, Carlos. HISTORIA GEOLÓGICA DEL BOSQUE HÚMEDO NEOTROPICAL . Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2012, vol.36, n.138, pp.57-77. ISSN 0370-3908.

The origin and development of the neotropical rainforest are still a mystery. Angiosperms, which dominate modern forests, originated during the early Cretaceous (∼140 Ma). During the Cretaceous, however, the neotropical forest was dominated by gymnosperms and ferns. It was not multi-stratal and had a low photosynthetic potential. The fall of a meteorite 65 Ma ago transformed the neotropics. Forests that evolved after the meteorite event became multistratified. The canopy was dominated by angiosperms and had high photosynthetic potential, similar to modern tropical forests. Over the past 60 m.y., the climate of the tropics has varied greatly, with pronounced global warmings and coolings. Forest diversity increased during the warmings and decreased during the coolings. In the last 10 m.y., the savannas have greatly expanded. The fossil record suggests that extant tropical plants already had the genetic variability to cope with high temperatures and CO₂ levels.

Keywords : Diversity; Cenozoic; Cretaceous; Tropical forests.

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