Science reveals flowering plants survived K-Pg extinction

The K-Pg event resulted in the elimination of at least 75 percent of all Earth’s species, including the dinosaurs. However, the effect of this event on flowering plants has remained unclear, according to a statement by the scientists.

The statement said that Dr. Jamie Thompson of the Milner Centre for Evolution and Dr. Santiago Ramírez-Barahona of Universidad Nacional Autónoma de México examined evolutionary trees constructed from mutations in the DNA sequences of up to 73,000 living species of flowering plants.

'Birth-death' models to estimate extinction rates

The scientists deployed complex statistical methods, including “birth-death” models, which evaluate the extinction rates across geological eras.

Past research investigating fossil records implied that many species disappeared, but some survived long enough to blossom. These species maintained their presence and eventually diversified to dominate flowering plants today. The study revealed that 400,000 of the plant species are currently still thriving, and 300,000 of those are flowering plants.

Additionally, scientists employed the molecular clock method and checked DNA and protein sequences. They found that known plant species, such as the ancestors of orchids, magnolia, and mint, existed before the K-Pg event.  

Dr. Jamie Thompson stated: “After most of Earth’s species became extinct at K-Pg, angiosperms took the advantage, similar to the way in which mammals took over after the dinosaurs, and now pretty much all life on Earth depends on flowering plants ecologically.”

The study's results showed macroevolutionary resilience in angiosperms as a group helped them prevail over the K-Pg mass extinction occurrence due to the survival of higher lineage..

Dr. Ramírez-Barahona highlighted the flowering plants' remarkable ability to adapt, stating: “They use a variety of seed-dispersal and pollination mechanisms, some have duplicated their entire genomes and others have evolved new ways to photosynthesize.”

“This ‘flower power’ is what makes them nature’s true survivors,” Ramírez added.

The study was published in Biology Letters earlier today (September 13).

Abstract:

The Cretaceous–Palaeogene mass extinction event (K-Pg) witnessed upwards of 75% of animal species going extinct, most notably among these are the non-avian dinosaurs. A major question in macroevolution is whether this extinction event influenced the rise of flowering plants (angiosperms). The fossil record suggests that the K-Pg event had a strong regional impact on angiosperms with up to 75% species extinctions, but only had a minor impact on the extinction rates of major lineages (families and orders). Phylogenetic evidence for angiosperm extinction dynamics through time remains unexplored. By analysing two angiosperm mega-phylogenies containing approximately 32 000–73 000 extant species, here we show relatively constant extinction rates throughout geological time and no evidence for a mass extinction at the K-Pg boundary. Despite high species-level extinction observed in the fossil record, our results support the macroevolutionary resilience of angiosperms to the K-Pg mass extinction event via survival of higher lineages.