Why flowering plants survived Earth’s greatest extinction while dinosaurs did not

Flowering plants survived Earth’s worst disasters, including the asteroid strike that ended the dinosaurs, while many others vanished. A sweeping genomic analysis suggests ancient DNA doubling may have helped them endure upheaval, opening a new window on resilience in a warming world.

Sixty-six million years ago, a giant asteroid slammed into Earth and changed life forever. The impact wiped out all non-avian dinosaurs and devastated ecosystems across the planet. Fires spread, sunlight dimmed and food chains collapsed. Yet somehow, many flowering plants survived.

A new study from Ghent University suggests those survivors may have carried a hidden advantage deep inside their DNA. Researchers found that many flowering plants endured ancient climate catastrophes after accidentally duplicating their entire genomes.

The findings come from one of the largest analyses ever conducted on flowering plant genomes. Scientists studied 470 species and traced ancient genome duplication events across more than 100 million years of plant evolution. Their results revealed a striking pattern. Many successful genome duplications appeared during periods of severe environmental turmoil, including mass extinctions, rapid warming events and global cooling episodes.

“Whole-genome duplication is often seen as an evolutionary dead end in stable environments,” said author Yves Van de Peer of Ghent University. “But in harsh situations, it can provide unexpected advantages.”

Most living things inherit two sets of chromosomes, one from each parent. But flowering plants often break that rule. Through a process called polyploidy, plants can accidentally duplicate their entire genetic code.

Some crops already show this unusual trait. Bananas often carry three chromosome sets, while wheat can contain six. These extra copies create larger and more complex genomes.

Scientists have long debated whether this process helps or harms plants. Genome duplication comes with serious costs. Bigger genomes demand more energy and nutrients. They also increase the risk of harmful mutations and fertility problems.

Because of those drawbacks, most duplicated genomes disappear over time. Only a small number survive across millions of years.

At the same time, duplicated genes can create new opportunities. Extra copies allow genes to evolve different functions. Some may help plants tolerate heat, drought or darkness. Others may strengthen biological systems during periods of stress.

This contradiction has puzzled scientists for decades. Researchers call it the “polyploid paradox.” Polyploid plants appear frequently, yet only a few persist through evolutionary history.

To investigate this mystery, the research team assembled genomic data from 470 flowering plant species. The dataset covered nearly every major branch of flowering plant evolution.

Using more than 1,600 reference gene families, researchers built a large evolutionary tree showing how species diverged over time. They then combined the genetic data with information from 44 plant fossils to estimate when ancient genome duplications occurred.

The team identified 132 separate whole-genome duplication events across flowering plants.

Eudicots, one of the largest plant groups, contained 95 of these events. Monocots, which include grasses, accounted for 25 more. Some plant families showed especially high numbers. The grass family contained eight ancient duplications, while bean and mustard relatives each showed five.

Still, most plant lineages carried evidence of only one or two ancient duplications. That reinforced the central mystery. Genome duplication happens often, but very few duplicated genomes survive long-term.

When researchers mapped duplication events against Earth’s environmental history, the pattern became difficult to ignore.

The surviving duplications clustered around some of the most chaotic moments in planetary history.

Several appeared during ancient oceanic oxygen collapses in the Cretaceous Period. Another major wave occurred about 73 million years ago during a period of cooling temperatures and declining plant diversity.

One especially important peak appeared around 64 million years ago, near the asteroid-triggered extinction event that ended the reign of dinosaurs.

Another strong wave occurred during the Paleocene-Eocene Thermal Maximum, or PETM, roughly 56 million years ago. During that event, global temperatures rose between 5 and 9 degrees Celsius over about 100,000 years. Massive amounts of carbon entered the atmosphere, ecosystems shifted rapidly and many species disappeared.

The study also found duplication peaks during the Eocene-Oligocene Transition and the Middle Miocene Climatic Transition, both periods marked by dramatic cooling and ecosystem upheaval.

Monte Carlo statistical analyses showed these links were unlikely to be random. Genome duplication waves appeared significantly closer to extinction events and climate disruptions than expected by chance.

The researchers believe environmental collapse may temporarily flip the normal rules of evolution.

In stable ecosystems filled with competing species, polyploid plants may struggle. Their larger genomes can slow growth and create reproductive problems.

But during mass extinctions or severe climate shifts, competition weakens. Entire ecosystems open up. Under those conditions, the advantages of extra genetic material may outweigh the costs.

Duplicated genes can provide flexibility. Some may help plants tolerate temperature swings, water stress or reduced sunlight. Others may allow faster adaptation to unfamiliar environments.

The study found a strong inverse relationship between species diversity and successful genome duplication establishment. In simpler terms, when ecosystems contained fewer competing species, duplicated genomes survived more often.

The findings suggest that ecological disasters may create rare evolutionary windows where polyploid plants gain an edge.

“While the current climate is warming at a much faster rate, what we see from the past suggests that polyploidy may help plants cope with these stressful conditions,” Van de Peer said.

The research also sheds light on how flowering plants became so successful across Earth’s history.

Flowering plants now dominate ecosystems worldwide. They provide food, oxygen and habitat for countless species, including humans. Their survival through repeated climate disasters helped shape the modern world.

The study suggests that ancient genome duplications may have played a major role in that resilience.

Researchers caution that several limitations remain. Fossil records are incomplete, and dating ancient genome duplications remains difficult. Global climate estimates may not fully capture local environmental conditions faced by individual plants.

Still, the enormous genomic dataset strengthens the evidence that these duplications did not survive randomly. Instead, they repeatedly appeared during times when Earth itself was under stress.

That insight feels especially relevant today.

Modern climate change is unfolding far faster than many ancient warming events. Ecosystems across the world already face rising temperatures, droughts and habitat disruption.

Scientists do not yet know whether modern plants will respond similarly. But the fossil and genomic record suggests that genetic duplication may once again become important during periods of environmental instability.

This research could help scientists better understand how plants adapt to severe environmental stress. By studying how ancient genome duplications improved survival during past climate crises, researchers may uncover genetic traits linked to heat tolerance, drought resistance and resilience.

That knowledge could eventually support agriculture and food security. Plant breeders may use insights from polyploid species to develop crops that better withstand rising temperatures and changing weather conditions. Since many important crops already contain duplicated genomes, understanding these mechanisms may improve future breeding strategies.

The findings also offer important clues for conservation biology. Scientists may identify which plant groups are most likely to adapt to rapid climate change and which species remain more vulnerable. This could guide ecosystem protection efforts as environmental conditions continue shifting worldwide.

Most importantly, the study shows that Earth’s deep history still contains lessons for humanity’s future. Ancient plants survived some of the planet’s most extreme disasters through unexpected genetic flexibility. Understanding those survival strategies may help scientists prepare for the environmental challenges unfolding today.

Research findings are available online in the journal Cell.

The original story "Why flowering plants survived Earth’s greatest extinction while dinosaurs did not" is published in The Brighter Side of News.

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