The skillful early adaptation of plants to their environment allowed their survival. They knew how to modify their behavior and evolved by taking advantage of multiple factors in their favor. The incredible strategy of plants to spread around the world changed our planet forever.
The reproductive evolution of flowering plants (angiosperms) is traditionally linked to the biotic crisis at the end of the Cretaceous. But new research from the University of California, Berkeley (United States) refutes this. They suggest that angiosperm dispersal ecologies had already diversified by then.
Flowering plants
The study is published in 'Science'. And it is based on an analysis of flowering plant diaspores (the units comprising seeds and associated structures) from a Late Cretaceous fossil forest site in New Mexico. Flowering plants have a remarkable diversity in the size and shape of fruits and seeds. What this reflects is a morphology adapted to dispersal by wind, water and animals.
This diversity is thought to have originated during the Paleogene, despite an earlier increase in angiosperm abundance and diversification throughout the Cretaceous. In this work, the researchers suggest an earlier origin of variation in angiosperm seeds and fruits. They describe a relatively well-preserved collection of 77 diaspore morphotypes from a Late Cretaceous fossil forest in New Mexico, USA. This one features fleshy fruits and an average weight similar to that of a blueberry.
Dispersion
It is true that they were probably dispersed by vertebrates. But its appearance could have been part of the transition towards humid and shady tropical forests. So it couldn't necessarily have been driven by vertebrate diversification. The incredible strategy of plants to distribute their seeds tells us about their evolutionary success. The results expand our understanding of forest ecology and plant-animal interactions during the first half of angiosperm evolutionary history.
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