The Asteroid Killed the Dinosaurs. The Flowering Plants Endured.
The Asteroid Killed the Dinosaurs. The Flowering Plants Endured.
Spring still does this to me: the green gets deeper every year, and somewhere in it I find myself back at the moment I handed someone a bouquet and asked a question I'd been rehearsing for weeks. That memory is sharper than most things I actually understand about flowers. For some people, though, the same bloom that built my best memory is the reason their eyes are running by April — proof that the prettiest thing in the yard can also be the thing working against you.
What the Crater Actually Proves
Most extinction stories rest on inference. This one doesn't have to. The asteroid that ended the Cretaceous left a hole in the ground big enough to measure, and geologists have spent decades doing exactly that.
The Chicxulub crater, buried under the Yucatan Peninsula, spans roughly 110 miles across — its structure mapped through drill cores, gravity readings, and magnetic surveys, not guesswork.
A 2021 analysis from Imperial College London found cosmic dust and iridium levels in the crater's cores running several times higher than the surrounding rock — a spike that chemically matches the K-Pg boundary's global iridium signature. Iridium is rare in Earth's crust and common in asteroids, so a layer like that reads as one event, recorded everywhere at once.
A 2010 peer-reviewed paper synthesizing that data estimated the impactor at roughly 7 to 10 miles wide, striking the Yucatan's carbonate shelf at tens of miles per second. The collision instantly carved a crater 95 to 125 miles across and triggered a tsunami across the surrounding seas.
The math is uncomfortable to sit with for very long. BBC reported on a 2019 site study describing a North American sediment layer interpreted as forming within hours to days of the strike, full of fish fossils tangled with glassy impact debris — tektites, dated to the K-Pg boundary, suggesting a mass burial in the middle of a wave that arrived the same day the sky changed.
No human witnessed it. The chemistry, the crater geometry, and most of the fossils point to the same event.
Three Out of Four Species Vanished. Flowering Plants Mostly Didn't.
The K-Pg extinction wiped out about 75 percent of animal species on Earth. Flowering plants weathered the same asteroid, the same firestorm, the same years of darkened skies — and at the level of their lineage, kept going.
A 2023 phylogenetic study found no detectable mass-extinction signal across major flowering plant lineages at the Cretaceous-Paleogene boundary, even as three-quarters of animal species disappeared in the same event. Researchers reconstructed diversity patterns across 73 plant lineages and found most maintained relatively stable trajectories across the impact, with long-term diversity continuing to climb afterward.
That doesn't mean nothing happened to plants. Some regional fossil records show real, sometimes severe losses in leaf and pollen diversity around the boundary — researchers don't dispute that part. What the 2023 analysis adds is a different scale: those local losses, however serious, never added up to a lineage-wide collapse.
One environment losing its flowers is a tragedy. An entire family tree losing its branches is an extinction. The data says flowering plants experienced more of the first than the second.
The old textbook version has the asteroid clearing out ancient conifers and ferns so flowering plants could finally take over — extinction as opportunity. The 2023 findings complicate that.
These plants weren't an opportunistic latecomer that got lucky when the competition died off. They were already diversified and distributed widely enough that the worst extinction event in 66 million years left their family tree standing, even as it leveled individual habitats — and ended almost everything else's lineage outright.
The Engineering Inside a Leaf
Surviving a global catastrophe isn't luck alone — it usually traces back to something built in long before disaster struck. For flowering plants, that something lived inside the leaf itself.
A 2012 study in Nature Communications compared fossil and modern leaf structures. Sometime during the Cretaceous, flowering plant leaves crossed a threshold — the internal plumbing for water and CO2 got short enough that gas could diffuse in faster than before. That sounds technical, and it is — but the result was a leaf that photosynthesized faster, grew quicker, and could be replaced more cheaply than the older plant designs around it.
That single shift didn't work alone. A 2019 review in Annals of Botany cataloged roughly thirty separate factors behind flowering plants' diversification — whole-genome duplications, varied flower shapes, adaptations to animal pollinators, and a wide range of seed and fruit strategies among them.
And the advantage compounded over time: a 2020 study in the Proceedings of the National Academy of Sciences found that as Earth's climate cooled over millions of years, conifer diversity declined while flowering plants kept expanding into new environments — flexibility, not any single trait, doing the heavy lifting.
Here's where the story gets less tidy, which is usually where it gets more honest. Researchers studying insect pollinators in 2022 and again in 2024 found that flowering plants didn't always diversify in step with their pollinators — in several lineages, the two timelines didn't move together at all.
Pollination by insects is part of the picture, but it isn't the whole engine. What actually carried these plants through 66 million years was several advantages stacking at once, not one elegant story doing all the work.
What a 74-Million-Year-Old Fruit Changes
The assumption that flowering plants exploded only after the dinosaurs vanished runs into a problem: the fossils don't support it.
A 2026 fossil discovery from a UC Berkeley research team — a volcanic ash deposit dated to roughly 74.6 million years ago, named the Dori's Tuff flora — preserved flowering trees bearing large fruit with thick rinds. That date sits well before Chicxulub, while dinosaurs were still very much alive.
The fruit's size and structure suggest it was built to be eaten and carried off by animals. That raises a real possibility: dinosaurs and these increasingly sophisticated flowering plants were sharing more than a forest — maybe a food web, for millions of years before either one's story ended.
It's a single fossil site, though, and the researchers behind it are careful to say so: stretching one well-preserved deposit into a global rule is exactly the kind of leap the evidence doesn't support yet.
This fits a longer arc that fossil and molecular-clock research has been tracing for years. Flowering plants likely originated by 125 to 135 million years ago, per the fossil record, then spread in geographic fits and starts rather than a single global wave — some regions favoring them early, others holding onto conifers and ferns for tens of millions more years.
The 2025 review tracking this calls it a stepwise rise, region by region, not a single cinematic takeover.
Put the timeline together and the asteroid stops looking like the plant kingdom's origin story and starts looking like one more event a well-established group happened to survive — much like it had made it through whatever came before, because the groundwork was already tens of millions of years in the making by the time the sky lit up over the Yucatan.
Why a 66-Million-Year-Old Survival Story Still Matters
An estimated 78 percent of living land plant species are flowering plants today, and most land animals — insects, birds, mammals — depend on that group directly or indirectly for food and shelter. That dependency has a 66-million-year-old hinge point running through it.
One caution researchers attach to all of this themselves: the asteroid's damage unfolded over years to decades. The biodiversity pressure plants and animals face now is compressed into decades to centuries by human activity — a faster clock, by a wide margin. Whether flowering plants' deep-time resilience says anything reassuring about the present is, by the researchers' own admission, an open question rather than a settled one.
The Slow Version of a Story Usually Told Fast
Strip the headline event away and what's left is a much longer story than 66 million years lets on.
Flowering plants likely existed by 125 to 135 million years ago. Over the next 25 to 35 million years, their range and diversity expanded — new flower shapes, leaf forms, and fruiting strategies emerging across different climates at different rates. By around 74.6 million years ago, the Dori's Tuff flora shows trees with substantial fruit already established, dinosaurs still walking among them.
Then, 66 million years ago, the asteroid struck, and roughly three-quarters of animal species disappeared in the geological blink that followed — while most flowering plant families and orders, per the phylogenetic data, came through it. Across the following Paleocene and Eocene epochs, those surviving lineages expanded into the niches the extinction emptied, building toward the dominance flowering plants hold over Earth's land surface today.
Reviewers studying this timeline are careful to flag where the dates and regional patterns still carry real uncertainty — competing models, in places, don't agree. A slow, uneven climb fits the fossil evidence better than a single triumphant turning point, even if the second version makes for a better headline.
The Argument Behind the Data
None of this settled quietly. When the Alvarez team first proposed the asteroid impact hypothesis in the 1980s, plenty of geologists and paleontologists pushed back hard, arguing that the Deccan Traps' prolonged volcanic eruptions and the climate shifts they caused mattered more than any single strike. The 2010 Science review that pulled the impact evidence together leaned firmly toward the asteroid as the primary driver — while still leaving room, in its own pages, for volcanism to have played some part.
That's not weak science. That's what honest science looks like while it's still working something out.
As drill cores and isotope analyses accumulated at Chicxulub, the weight of evidence shifted, and researchers who'd been skeptical of an impact-extinction link started coming around — a pattern that shows up again and again in the follow-up literature. A similar tension runs through the plant side of the story.
The old narrative, repeated in textbooks for decades, says flowers exploded once dinosaurs were gone. The 2023 phylogenetic work cuts against that.
Some researchers lean into flowering plants' resilience as the takeaway; others push back, citing how incomplete the fossil record still is and how much any reconstruction depends on the model used to build it. Both camps are working from the same data. They just don't agree yet on how hard to lean into the story it tells.
A Theory I Can't Quite Let Go Of
As a kid, it felt like there were a hundred different explanations for why the dinosaurs disappeared — which probably just meant nobody had a good one yet. The asteroid has since become the answer that holds up, the one the crater, the iridium, and the fossils all agree on.
But buried in the same research is something stranger: flowering plants were establishing themselves on roughly the same timeline the dinosaurs were running out of.
I keep landing on the same half-serious thought. Pollen allergies need pollen — and the flowering plants behind most of it didn't show up until partway through Earth's history. Dinosaurs lived alongside those plants for millions of years before the asteroid ever entered the picture.
Maybe, somewhere in that overlap, a few of them were dealing with something that had nothing to do with a crater in the Yucatan. I doubt it moved the extinction numbers. I can't quite stop picturing it anyway.
Frequently Asked Questions
Did the asteroid that killed the dinosaurs also kill flowering plants?
No — flowering plants show no detectable mass-extinction signal at the K-Pg boundary, even though roughly 75 percent of animal species died out in the same event. A 2023 phylogenetic study found most major flowering plant lineages maintained relatively stable diversity across the impact.
How big was the asteroid that hit Earth 66 million years ago?
The Chicxulub impactor is estimated at roughly 7 to 10 miles wide, based on the size of the crater it left beneath Mexico's Yucatan Peninsula. The crater itself spans about 110 miles across, mapped through drill cores and geophysical surveys.
Did flowering plants exist before the dinosaurs went extinct?
Yes — flowering plants likely originated 125 to 135 million years ago, well before the K-Pg extinction. A 2026 fossil find called the Dori's Tuff flora, dated to about 74.6 million years ago, shows flowering trees with large fruit already established while dinosaurs were still alive.
What evidence proves the Chicxulub crater caused the dinosaur extinction?
Drill cores from the crater show iridium and cosmic dust concentrations that chemically match the global iridium spike found at the K-Pg boundary on multiple continents. Iridium is rare in Earth's crust but common in asteroids, making this layer strong physical evidence of a single global impact event.
Why did flowering plants survive the mass extinction when dinosaurs didn't?
Researchers point to several compounding factors rather than one cause: more efficient leaf structures for photosynthesis, genetic flexibility from genome duplications, varied reproductive strategies, and wide geographic distribution by the time the extinction hit. No single trait explains it.
What percentage of plants on Earth today are flowering plants?
An estimated 78 percent of living land plant species are flowering plants, underpinning most of Earth's terrestrial food webs for insects, birds, and mammals.
Did dinosaurs and flowering plants live together?
Yes, for millions of years. One recently reported fossil site, the 74.6-million-year-old Dori's Tuff flora, shows dinosaurs sharing forests with flowering trees that bore fruit, hinting at feeding relationships well before the extinction event.
Sources & References
Imperial College London, "Space dust found in Chicxulub crater confirms asteroid's role in dinosaur extinction" (2021) —
imperial.ac.uk
Schulte, P. et al., "The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary," Science, 2010 —
doi.org
BBC News, "Chicxulub asteroid impact: Stunning fossils record dinosaurs' demise" (2019) —
bbc.com
Condamine, F. L. et al., "No phylogenetic evidence for angiosperm mass extinction at the Cretaceous-Palaeogene boundary," Nature Ecology & Evolution, 2023 —
PMC/NIH
Brodribb, T. J. & Feild, T. S., "A critical transition in leaf evolution facilitated the Cretaceous angiosperm revolution," Nature Communications, 2012 —
nature.com
Sauquet, H. & Magallon, S., "Thirty clues to the exceptional diversification of flowering plants," Annals of Botany, 2019 —
academic.oup.com
Condamine, F. L. et al., "The rise of angiosperms pushed conifers to decline during global cooling," PNAS, 2020 —
pubmed.ncbi.nlm.nih.gov
University of California, Berkeley, "New fossils upend catastrophist narrative that flowering plants flourished only after dinosaur extinction" (2026) —
berkeley.edu
Taylor, D. W. & Hickey, L. J., "Toward a new synthesis: Major evolutionary trends in the angiosperm fossil record," PNAS, 2000 —
pnas.org
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