These were the unlikely survivors after dinosaurs went extinct

When an asteroid hit the Earth 66 million years ago, it unleashed a violent force millions of times more massive than...

Posted: May 24, 2018 7:37 PM
Updated: May 24, 2018 7:37 PM

When an asteroid hit the Earth 66 million years ago, it unleashed a violent force millions of times more massive than an atomic bomb. Known as the Cretaceous-Paleogene fifth mass extinction event, it wiped out three-quarters of all plant and animal life on Earth -- including the dinosaurs.

A new study suggests that the impact also decimated Earth's forests, leading to the extinction of all the birds that lived in trees. But in a twist, the plucky survivors in the fiery aftermath proved to be ferns and hardy, ground-dwelling birds.

Ferns and ground-dwelling birds survived the fifth mass extinction, according to a new study

All of today's birds descended from the survivors

The study was published Thursday in the journal Current Biology.

Scientists also refer to the event as the K-Pg Chicxulub impact because it created the Chicxulub crater in what's now Mexico. During the initial impact, shock waves flattened trees in massive waves within a radius of nearly 1,000 miles. But what followed was probably even worse for the initial survivors of this apocalyptic event.

The intense heat generated by the impact would have sparked global wildfires, ravaging what was left of the forests. Vapor, rich in sulfates, triggered acid rain. Soot clogged the atmosphere, which put a damper on the photosynthetic activity that plants needed to survive or grow back. This lasted years, which kept the global climate from cooling.

Not only did the forest canopies collapse, they wouldn't be able to regrow. Any birds that roosted or perched in trees would've been homeless. The chance of surviving the asteroid was already slim for tree-dwelling birds; eliminating their habitat ensured extinction.

Researchers from the United States, England and Sweden studied the fossil record from North America to New Zealand, looking closely at charcoal remains of trees, fossilized pollen and fern spores, and bird fossils. The combination of samples provided a bigger picture of what the world was like during the aftermath of the impact.

"To me, it's really exciting to see that combining insights from the bird fossil record and the plant fossil record can allow us to piece together a major macroevolutionary story that took place over 66 million years ago," Daniel Field, lead study author and an evolutionary paleontologist at the University of Bath's Milner Centre for Evolution, wrote in an email. "It speaks to the power of collaborative science, and the importance of the fossil record for understanding the life in the modern world."

A perilous life on the ground

The ground-dwelling birds that survived would not have had an easy existence. It's likely that smaller ground-dwelling birds experienced a catastrophic loss. They probably lived off the hardiest grains and seeds that endured the impact, as well as insects. Many small-bodied birds today eat insects, and this trait can be traced to the surviving birds 66 million years ago.

"My guess is that any surviving birds would have been fairly skinny for a few years in the immediate aftermath of the asteroid impact," Field said.

Their fossils reveal that the ground-dwelling birds had long, sturdy legs, like those of a kiwi or an emu, nothing like the delicate legs of perching birds.

They can be compared to today's tinamous, small-bodied, flying and ground-dwelling relatives of ostriches and emus that live in Central and South America. Being small, flying and living on the ground were probably all features that would have favored survival across the mass extinction event, Field said.

But the ground-dwelling birds that survived carried a lasting legacy beyond the tinamous.

"Today, birds are the most diverse and globally widespread group of terrestrial vertebrate animals -- there are nearly 11,000 living species," Field said in a statement. "Only a handful of ancestral bird lineages succeeded in surviving the mass extinction event 66 million years ago, and all of today's amazing living bird diversity can be traced to these ancient survivors."

Ferns were also the big survivor, as opposed to trees, because their tiny, single-celled spores dispersed quickly. Spores are much smaller than seeds, and they can easily grow in a damp area. Ferns are usually among the quickest plants to return after natural disasters.

"The spores are tiny -- you could fit four across a single strand of your hair," Regan Dunn, study co-author and paleontologist at the Field Museum in Chicago, said in a statement.

So how long would it take the ferns to thrive? They can colonize an area quickly, but it still takes time.

"It may have taken on the order of 100 years for the 'fern spike' to begin, and about 1,000 years for forest communities to rebound," Field said. "Once forests were back, the ancestors of today's modern tree-dwelling birds could -- and did -- move into the trees. By a couple of millions of years after the asteroid impact, we have direct evidence of arboreal fossil birds."

Past could mirror the future

Studying whole paleoecosystems shows how life on Earth has evolved through all the trials and tribulations of the past, Dunn said in an email.

But it's also incredibly important to study what happened during the fifth mass extinction because many scientists believe we're entering the sixth mass extinction.

"Human activity is causing deforestation on a massive scale," Field said. "We know that the diversity of bird communities is impacted by the availability of forests -- when forests are cut down in favor of, for example, palm oil monoculture, bird diversity is slashed. It's probable that, if this kind of deforestation continues unabated, it will leave an indelible signature on the evolution of birdlife."

Dunn added that "By studying this event, we learn about what happened to biodiversity in the past following destruction of Earth's ecosystems and how long it took for biodiversity to recover. On a human time-scale, recovery is very long indeed. We need to take these lessons to heart and act now to preserve today's profound biodiversity."

Oregon Coronavirus Cases

Data is updated nightly.

Cases: 176157

Reported Deaths: 2461
CountyCasesDeaths
Multnomah35145568
Washington23569229
Marion20282299
Clackamas15499204
Lane11722144
Jackson9984127
Umatilla798483
Deschutes721472
Linn418763
Yamhill412575
Klamath353759
Polk346452
Malheur343058
Josephine307862
Douglas305765
Benton275418
Jefferson207432
Coos198431
Columbia155426
Union141824
Lincoln130520
Wasco130228
Hood River113029
Morrow108115
Clatsop9008
Crook89119
Baker86114
Curry5999
Tillamook5833
Grant4204
Lake4147
Harney3136
Wallowa1575
Gilliam571
Sherman571
Wheeler261
Unassigned00

California Coronavirus Cases

Data is updated nightly.

Cases: 3723446

Reported Deaths: 61122
CountyCasesDeaths
Los Angeles122964123668
Riverside2976204547
San Bernardino2949734561
San Diego2753683674
Orange2691764900
Santa Clara1173172017
Kern1080131331
Sacramento1016651647
Fresno1007021646
Alameda855831477
Ventura803321002
San Joaquin717351334
Contra Costa67157782
Stanislaus605831032
Tulare49443831
Monterey43301364
San Mateo41226560
San Francisco36094529
Santa Barbara33926446
Solano32047239
Merced31289453
Sonoma29720311
Imperial27995719
Kings22781245
Placer21908283
San Luis Obispo20991257
Madera16289240
Santa Cruz15666204
Marin13868226
Yolo13572200
Shasta11747219
Butte11601196
El Dorado9797109
Napa971579
Sutter9299109
Yuba612744
San Benito598963
Lassen567924
Tehama544556
Nevada448975
Tuolumne408664
Mendocino399347
Humboldt363138
Amador362946
Lake341643
Glenn235825
Colusa220416
Calaveras206252
Siskiyou196521
Inyo141838
Del Norte12907
Mono12744
Plumas6936
Modoc4904
Mariposa4287
Trinity3985
Sierra1100
Alpine880
Unassigned440
Medford
Clear
44° wxIcon
Hi: 74° Lo: 41°
Feels Like: 44°
Brookings
Partly Cloudy
53° wxIcon
Hi: 72° Lo: 43°
Feels Like: 53°
Medford
Clear
44° wxIcon
Hi: 56° Lo: 26°
Feels Like: 44°
Medford
Partly Cloudy
44° wxIcon
Hi: 72° Lo: 44°
Feels Like: 44°
Klamath Falls
Clear
41° wxIcon
Hi: 59° Lo: 38°
Feels Like: 33°
Clearing tonight, sunny and warmer tomorrow
KDRV Radar
KDRV Fire Danger
KDRV Weather Cam

Community Events