Modern Birds came from Non-Arboreal Chicxulub Survivors

[BillTre]

Here is a new paper (open access) on the origins of modern birds.
Birds evolved from dinosaurs and are the only survivors of the dinosaurs, which went extinct after the Chicxulub impact devastated ecology worldwide.
Trees were wiped out so arboreal birds lost their environment and went extinct.
All modern birds were derived from non-arboreal birds that survived the Chicxulub impact.

Paper Highlights:

• The end-Cretaceous mass extinction devastated forest habitats globally
• Tree-dwelling birds failed to persist across the end-Cretaceous extinction event
• All bird groups that survived the end-Cretaceous extinction were non-arboreal
• The early ancestors of many modern tree-dwelling bird groups were ground-dwelling

 

[Bystander]

Thousand year resolution on a 65-70 Ma event? The palynological data?

 

[jim mcnamara]

@Bystander - figure 3 here: https://www.cell.com/action/showImagesData?pii=S0960-9822(18)30534-7
is based on palynology. Apparently the authors believe it is possible to resolve ~1000 years very near and above the p/k boundary, at the site mentioned.

I'm skeptical as well.

 

[BillTre]

There are areas with very good time resolution for sediments due to rapid deposition resulting in thick layers per time.
They also have a very distinct layer (with world wide distribution) of a variety of material directly related to the impact, such as iridium and solidified micro-droplets of melted rock from the impact.

A few years ago, I read about how someone figured out which season the impact occurred in based on these layers and the pollen or spores or somethin like that in China.

The palynological data?

Is this the same as paleontological?

 

[Bystander]

same as paleontological?

"Palyn" equals pollen layers/layering.

 

[BillTre]

OK thanks for informing me!

 

[jim mcnamara]

@BillTre have look at varves - https://en.wikipedia.org/wiki/Varve They are preserved (when fossilized) as evidence of glaciers and vegetation changes (annual pollen deposits from fairly old formations of sedimentary rock) The picture on the page shows Pleistocene varves.

They also are found in modern deposits.

 

[BillTre]

Here is a Science magazine news article on this publication.