The expansion of angiosperms—flowering plants—represents one of the most profound ecological transformations of the Mesozoic, comparable in long-term impact to major tectonic events or mass extinctions. It was not a sudden revolution, but a gradual process that accelerated during the Cretaceous, reshaping terrestrial landscapes, food webs, and the relationships between plants and animals.
Before their rise, terrestrial ecosystems were dominated primarily by gymnosperms such as conifers, cycads, and ginkgos. These plants formed extensive but relatively uniform forests, characterized by slow reproductive cycles and limited dispersal strategies. Angiosperms introduced a fundamentally different model: specialized flowers, protective fruits, and far more efficient and flexible reproductive systems.
Flowering plants enabled new forms of biological interaction. Coevolution with insect pollinators produced highly specialized relationships, driving rapid increases in both plant and insect diversity. At the same time, fruits facilitated seed dispersal by vertebrates, allowing angiosperms to spread quickly across a wide range of environments.
These changes had direct consequences for Mesozoic herbivores. New plant types introduced new food resources, favoring adaptations in dentition, digestive systems, and feeding behavior among many herbivorous dinosaurs. These shifts propagated upward through food webs, influencing predators and reshaping the overall structure of terrestrial ecosystems.
Angiosperms also altered the physical landscape. Their rapid colonization of floodplains, river margins, and disturbed environments transformed soil dynamics, moisture retention, and erosion patterns. Terrestrial habitats became more heterogeneous, fragmented, and dynamic, creating a greater diversity of ecological niches.
By the end of the Cretaceous, angiosperms were no longer a marginal component of terrestrial ecosystems but a dominant force in many regions. Although they did not completely replace gymnosperms, they fundamentally redefined how land ecosystems functioned and established the foundation of modern terrestrial landscapes.
The rise of flowering plants was not merely a botanical shift. It was a deep reorganization of the terrestrial world, with consequences that unfolded over millions of years and continue to shape Earth’s biosphere today.