The Grand Diversity of Plants Took Time

A recent study examines the diversity and complexity of plants throughout Earth’s paleontological record. A team led by Andrew B. Leslie (Stanford University) published an article in the journal Science entitled “Reproductive Innovations & Pulsed Rise in Plant Complexity.” While that title sounds complicated, the implications are not.

In short, as land plants have evolved, so too has their complexity and diversity, particularly in their reproductive structures and strategies. Two key “pulses” are noticeable. First, the origin of seeds, which took place in the late Devonian Period some 370 million years ago. Second, the origin of flowering plants during the mid-Cretaceous Period 80 to 115 million years ago.

The authors conclude that while animals expanded and diversified morphologically relatively early in Earth history, plant complexity occurred relatively late, with much expansion only near the end of the reign of the dinosaurs after a period of relative hiatus that lasted nearly 250 million years. The authors conclude that plant diversity occurred in two pulses or “bursts” rather than gradually, contradicting the traditional evolutionary theory.