New research explores how "flower power" persisted and became a dominant plant type during a mass extinction event 66 million years ago. A recent study by scientists from the University of Bath in the UK and the National Autonomous University of Mexico shows that flowering plants have largely avoided the catastrophic effects of the mass extinction event that wiped out the dinosaurs 66 million years ago. Although they experienced some species loss, this catastrophic occurrence played a key role in helping flowering plants become the dominant type of plants today.
While the mass extinction 66 million years ago devastated many species, recent research shows that flowering plants were relatively unscathed. Researchers dug into the DNA of numerous flowering plant species and found that many of today's angiosperm families, including magnolias and orchids, have roots that date back to the age of the dinosaurs.
Throughout Earth's history, numerous mass extinctions have occurred. The most famous of these is an asteroid impact 66 million years ago that reshaped the trajectory of life on our planet.
The Cretaceous-Paleogene (K-Pg) extinction event wiped out at least 75% of all species on Earth, including the dinosaurs, but so far it's unclear what impact it had on flowering plants.
Plants do not have bones or exoskeletons like most animals, which means there are relatively few fossils compared to animals, so understanding the timeline of evolution from fossil evidence alone is difficult.
Dr Jamie Thompson of the Milner Center for Evolution and Dr Santiago Ramírez-Barahona of the National Autonomous University of Mexico analyzed an evolutionary tree built from mutations in the DNA sequences of up to 73,000 living flowering plants (angiosperms).
Using sophisticated statistical methods, they fitted a "birth-death" model to estimate extinction rates across geological time.
While the fossil record shows that many species did disappear, the lineages to which they belonged, such as families and orders, survived, thrived, and then became dominant—of the approximately 400,000 plant species living today, approximately 300,000 of them are flowering plants.
Molecular clock evidence shows that the vast majority of today's angiosperm families existed before the K-Pg event: species including the ancestors of orchids, magnolias and mints all shared the Earth with dinosaurs.
Dr Jamie Thompson said: "After the extinction of most species on Earth at the K-Pg, angiosperms took over, much in the same way mammals took over after the dinosaurs, and now almost all life on Earth depends on the ecology of flowering plants".
So what makes them survive despite being unable to move and relying on the sun for energy? Dr. Ramírez-Barahona said: "Flowering plants have extraordinary adaptability: they use a variety of seed dispersal and pollination mechanisms, some have duplicated their entire genomes, and others have evolved new ways of photosynthesis. This 'flower power' therefore makes them true survivors of nature."