[While the extinction affected some flower species, most lineages
survived and the catastrophe may have helped them become a dominant
form of plant life.]
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SUNDAY SCIENCE: WIPING OUT THE DINOSAURS LET COUNTLESS FLOWERS BLOOM
 
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Jack Tamisiea
September 12, 2023
New York Times
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_ While the extinction affected some flower species, most lineages
survived and the catastrophe may have helped them become a dominant
form of plant life. _

Lacinipetalum spectabilis, a 64-million-year-old flower found in
Patagonia. The scale bar represents two millimeters., Nathan Jud

 

When a mountain-size slab of space rock
[[link removed]] rammed
into the Yucatán Peninsula 66 million years ago
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the fallout was apocalyptic
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Tsunamis washed away coastlines, raging fires engulfed forests and
dust and debris blotted out the sun for months. Roughly three-fourths
of the planet’s species, most notably non-avian dinosaurs, were
wiped out.

But one group appears to have weathered the maelstrom. In a paper
published Wednesday in the journal Biology Letters
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researchers present evidence that flowering plants survived the
Cretaceous-Paleogene, or K-Pg, mass extinction
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unscathed compared with other living things on Earth at the time. The
catastrophe may have even helped flowering plants blossom into the
dominant green things they are today.

“It’s just bizarre to think that flowering plants survived K-Pg
when dinosaurs didn’t,” said Jamie Thompson, an evolutionary
biologist at the University of Bath and one of the authors of the
study.

Flowering plants are known to scientists as angiosperms. They
originated in the early Cretaceous, and were often overshadowed by
older groups like conifers and ferns. But they rapidly diversified as
mass extinction loomed.

To determine how flowering plants fared during the K-Pg extinction
event, Dr. Thompson teamed up with Santiago Ramírez-Barahona, an
evolutionary geneticist at the National Autonomous University of
Mexico. The pair were initially hindered by a lack of fossil flowers,
which are scarce compared with fossilized bones. Some of the largest
angiosperm lineages today, like orchids, barely show up in the fossil
record.

To uncover the evolutionary insights missing from the fossil record,
the researchers analyzed two evolutionary trees containing more than
100,000 species of living angiosperms. These sprawling data sets,
known as phylogenies, were calibrated using molecular clues that allow
scientists to group related species together and determine when
certain lineages diverged. Together, the phylogenies lay out an
evolutionary timeline of when the ancestors of modern angiosperm
lineages emerged and when they died out.

The researchers discovered something surprising. While many angiosperm
species died out with the dinosaurs, pterosaurs and marine reptiles
— especially those living near the asteroid impact crater — the
larger lineages of flowering plants survived the extinction event and
exhibited a relatively constant rate of extinction through time.

“I think that is actually in perfect step with the plant fossil
record,” said Paige Wilson Deibel, a paleobotanist at the Burke
Museum in Seattle who studies fossils from the K-Pg boundary in
northeastern Montana and was not involved in the new study. “There
is really high species-level extinction but the major lineages all
seem to have survived.”

This contrasts starkly with the evolutionary tree of dinosaurs.
“Non-avian dinosaurs lost so many species, they lost entire
lineages, which we don’t see in angiosperms,” Dr. Thompson said.

While more work is needed to determine how angiosperms survived one of
the deadliest extinctions in Earth’s history, the researchers posit
that their adaptability played a role. Because flowering plants are
pollinated by both insects and wind, they have significant
reproductive flexibility. Their vast diversity — by the end of the
Cretaceous, grasses, sycamore and magnolia trees, and aquatic
waterlilies had all appeared — may have also helped them survive the
devastation.

As Earth’s climate stabilized and life recovered, flowering plants
took over terrestrial ecosystems. In 2021, researchers comparing
Colombian fossils from before and after the K-Pg boundary found
that the extinction allowed angiosperms to dominate
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This led to the first rainforests, which remain hotbeds of flowering
plant diversity.

Dr. Ramírez-Barahona said this trend likely occurred in ancient
ecosystems worldwide. “Before and after the K-Pg impact the whole
ecological composition changed,” he said. “They restructured
themselves into these new flowering ecosystems.” Today, nearly 80
percent of all terrestrial plants are angiosperms.

In this way the impact that doomed the dinosaurs gave rise to modern
ecosystems. Instead of giant reptiles, these habitats were populated
by mammals, who had persisted through the mass extinction along with
flowering plants and were primed for a similar explosion in diversity.

After the K-Pg boundary, “we’re starting to see plants and animals
that we recognize,” Dr. Wilson Deibel said. “It’s in this really
dynamic time of giant environmental disasters and mass extinctions
that the environment becomes analogous to what we see today.”

_JACK TAMISIEA is a science writer based in Washington D.C. who covers
natural history and the environment. He loves uncovering new stories
from old museum collections and highlighting the quirks of both
strange and familiar species. His writing has appeared in The New York
Times, National Geographic, Scientific American, The Atlantic, Hakai
Magazine, Johns Hopkins Magazine, Smithsonian Magazine and other
popular science publications._

_Jack graduated from the University of Southern California where he
studied Environmental Studies and English and recently received a
Masters in Science Writing at Johns Hopkins University, where he
received the David Everett Award for Outstanding Thesis for his
collection, “Pickled in Jars and Crammed into Drawers: Uncovering
new stories from old museum collections.”_

_He has always been fascinated by fossils, reptiles and amphibians,
and is passionate about capturing their curious nature
through writing
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always on the lookout for a natural history museum or national park!_

_THE NEW YORK TIMES is a daily newspaper based in New York City with
a worldwide readership reported in 2022 to comprise 740,000 paid print
subscribers, and 8.6 million paid digital subscribers. Founded in 1851
as the New-York Daily Times, it is published by The New York Times
Company._

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THE “CRISIS IN COSMOLOGY” IS PURE EXAGGERATION
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There are a few clues that the Universe isn't completely adding up.
Even so, the standard model of cosmology holds up stronger than ever.
ETHAN SIEGEL
Starts with a Bang/Big Think
September 6, 2023

* Science
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* Evolution
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* mass extinctions
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* flowers
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* Cretaceous period
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* diversity
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