Article Source: Modern snakes evolved from a few survivors of dino-killing asteroid (https://www.sciencedaily.com/releases/2021/09/210914111218.htm)
Article Summary:
The survivors of the asteroid impact that ended the Cretaceous period have evolved into new niches that created modern-day snakes. Researchers came to this conclusion by comparing the fossils of modern snakes and finding genetic variance. This variance is believed to be the result of Cretaceous snakes that avoided extinction by hiding underground and later coming to the surface when their competitors died. Without competition, the snakes were free to explore new habitats and acquire many different genetic traits to optimize their survival.
Journal Source: Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction By: Catherine G. Klein , Davide Pisani, Daniel J. Field, Rebecca Lakin, Matthew A. Wills & Nicholas R. Longrich (https://www.nature.com/articles/s41467-021-25136-y)
Journal Summary:
By gathering data from post-Cretaceous squamate fossils, Catherine G. Klein and five other researchers recreate a time-calibrated phylogeny of crown snakes. Previous findings about post-Cretaceous snakes were deemed “…difficult to assess.”, prompting the team to attempt making their own model. Overall, this model illuminates how the diversity of snakes truly and widely expanded after the Cretaceous extinction.
Comparisons:
- The online article claims that one of the co-authors described the end of the Cretaceous as “creative destruction” and notes that events like extinctions are driving forces for “evolutionary change”. The phrase creative destruction is not used in the journal article.
- The journal article specifies that the diversification occurred with crown snakes, and “…terrestrial ecosystems recovered rapidly.” (Klein et al. 2) after the Cretaceous extinction.
- Both the online article and journal article agree that that there was a large amount of evolutionary divergence between the snakes in the study: “Shape disparity remained relatively constant throughout the Late Cretaceous, illustrating substantial morphological diversity early in the evolutionary history of total-clade snakes.” (Klein et al. 2) “…today including almost 4000 living species, started to diversify around the time that an extra-terrestrial impact wiped out the dinosaurs…all living snakes trace back to just a handful of species that survived the asteroid impact 66 million years ago.” (ScienceDaily)
- Interviews with the authors of the study in ScienceDaily’s article help contextualize the results of the study.
