BUFFALO, N. Y. A study published in Science Advances on April 1 reveals a new hypothesis that may explain why European cave bears went extinct during past climate change periods. The research was motivated by controversy in the scientific literature as to what the animal (Ursus spelaeus) ate and how that affected their demise.
The new hypothesis emerged, in part, from computational analysis and computer biting simulations conducted in the laboratory of Jack Tseng, PhD, assistant professor of pathology and anatomical sciences in the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo.
Tseng is a co-author on the paper with corresponding authors Borja Figueirido, PhD, and Alejandro Prez-Ramos, PhD, first author, both of the Departamento de Ecologia y Geologia of the Universidad de Malaga, Spain.
Dietary dilemma
Cave bears were a species of bear (Ursus spelaeus) that lived in Europe and Asia that went extinct about 24,000 years ago. According to Figueirido, researchers have proposed different diets for cave bears, ranging from pure herbivory to carnivory or even scavenging.
Knowing the feeding behaviour of the cave bear is not a trivial aspect, he said. Feeding behaviour is intimately related to its decline and extinction.
He noted that two main hypotheses, not necessarily exclusive, have been proposed to explain cave bear extinction: a human-driven decline, either by competition for resources or by direct hunting; or a substantial demise in population sizes as a result of the climatic cooling that occurred during the late Pleistocene which caused vegetation to wane.
Previous research shows that cave bears were primarily herbivorous at least from 100,000 to 20,000 years ago. But even during the cooling periods, when vegetation productivity waned, these bears didnt change their diets. The researchers propose that this dietary inflexibility, combined with competition for cave shelters by humans, is what led to their extinction.
To find out if there were biomechanical explanations behind their inflexible diets, meaning that the bears werent physically capable of adjusting their diets effectively during times of limited vegetation resources, the researchers analyzed three-dimensional computer simulations of different feeding scenarios.
Critical sinuses
They were especially interested in the sinuses of the bears because large paranasal sinuses allow for greater metabolic control, critical to survival during hibernation.
Our study proposes that climate cooling probably forced the selection of highly developed sinuses, which in turn led to the appearance of the characteristic domed skull of the cave bear lineage, said Alejandro Prez-Ramos.
Tseng explained that when the sinus system expands, the act of chewing may cause more or less strain on the skull. In both humans and bears, the sinus system lightens the weight of the face, reducing the amount of bone tissue needed to grow the skull.
Mechanically speaking, being thickheaded may not be a bad thing because more bone means more structural strength, he said. However, our findings support the interpretation that requirements for sinus system function in cave bears necessitated a trade-off between sinus development and skull strength.
Tseng and Prez-Ramos, who spent three months at UB to learn the procedure, used a biomechanical simulation methodology to estimate the biting stresses and strains in different bear species and different models of them. The bear skull specimens used were from several European institutions, where CT scans had been done on them, as well as the scientific CT repository, also known as the digital morphology library, at the University of Texas at Austin.
They found that the development of paranasal sinuses in cave bears caused the cranial dome to expand upward and backward from the forehead, changing the geometry of the bears skull.
This geometrical change generated a mechanically suboptimal cranial shape, with a very low efficiency to dissipate the stress along the skull, particularly when biting with the canines or carnassials, the teeth most often used by predatory mammals, saidPrez-Ramos.
When the sinus system expands, Tseng explained, it results in bone reduction relative to the size of the skulland therefore less structural support to resist the physical forces that chewing generates. Although other mammals with expanded sinuses, such as hyenas, appear to have evolutionarily modified their skull shape to effectively deal with decreased structural support, cave bear skulls showed compromised biomechanical capability compared to living bear species.
Through the use of new techniques and virtual methods, such as biomechanical simulations across each tooth and the comparative internal anatomical study of the paranasal sinuses, we propose that large sinuses were probably selected in cave bears in order to be able to hibernate for longer periods with very low metabolic costs, said Prez-Ramos.
Ultimately, though, that trade-off may have resulted in the extinction of the species, a finding that also has relevance to humans, Tseng said.
Being able to stay alive during the coldest periods would have been equally important to human and bear alike, he said. The success or demise of prehistoric megafauna, such as cave bears, provide crucial clues as to how humans may have out-competed and out-survived other large mammals during a critical time for the evolution of our own species.
Funding for this project was provided by theSpanish Ministryof Economy and Competitivenessgrants CGL2012-37866,CGL2015-68300P, andBES-2013-065469. The Computational Cell Biology, Anatomy, and Pathology GraduateProgram in the Jacobs School provided logistical support for Alejandro Prez-Ramos residence in Tsengs laboratory.
View original post here:
- History of Evolution | Internet Encyclopedia of Philosophy - December 9th, 2016 [December 9th, 2016]
- Evolution - Bulbapedia, the community-driven Pokmon encyclopedia - December 12th, 2016 [December 12th, 2016]
- What is Evolution - explanation and definitions - December 21st, 2016 [December 21st, 2016]
- Evolution (2001 film) - Wikipedia - January 28th, 2017 [January 28th, 2017]
- EvolutionM.net - Mitsubishi Lancer Evolution | Reviews, News ... - February 1st, 2017 [February 1st, 2017]
- YMCA evolution continues at lake - Gaston Gazette - February 7th, 2017 [February 7th, 2017]
- Ivanka Trump's Beauty Evolution, From 1998 to Today Watch - Us Weekly - February 7th, 2017 [February 7th, 2017]
- Lumpy, hairy, toe-like fossil could reveal the evolution of molluscs - The Guardian - February 7th, 2017 [February 7th, 2017]
- How Evolution Alters Biological Invasions - ScienceBlog.com (blog) - February 7th, 2017 [February 7th, 2017]
- Cultural evolution and the mutilation of women - The Economist - February 7th, 2017 [February 7th, 2017]
- Late-night hosts on the evolution of Trump: 'Dickish to dictatorish' - The Guardian - February 7th, 2017 [February 7th, 2017]
- Gold's Gym Regina rebrands to become Evolution Fitness - Regina Leader-Post - February 7th, 2017 [February 7th, 2017]
- Incremental Versus Radical Innovation: A Response to Josh Swamidass on Evolution and Cancer - Discovery Institute - February 7th, 2017 [February 7th, 2017]
- Blockchain: Investment (R)Evolution For Developing Markets - Forbes - February 7th, 2017 [February 7th, 2017]
- See the Evolution of the Famed Porsche 911 in 7 Photos - WIRED - February 7th, 2017 [February 7th, 2017]
- Exhibition charts 500 years of evolution of robots - Phys.Org - February 7th, 2017 [February 7th, 2017]
- How evolution turned ordinary plants into ravenous meat-eaters - Wired.co.uk - February 7th, 2017 [February 7th, 2017]
- Are Evolution Fresh Drinks 'Poison'? - snopes.com - February 7th, 2017 [February 7th, 2017]
- Non-Chromosomal DNA Drives Tumor Evolution - The Scientist - February 8th, 2017 [February 8th, 2017]
- Chimpanzee feet allow scientists a new grasp on human foot evolution - Phys.Org - February 8th, 2017 [February 8th, 2017]
- 'Goldilocks' genes that tell the tale of human evolution hold clues to variety of diseases - Science Daily - February 8th, 2017 [February 8th, 2017]
- Pac-Man is Coming to 'The Sandbox Evolution' Next Week - Touch Arcade - February 9th, 2017 [February 9th, 2017]
- Chimpanzee feet allow scientists a new grasp on human foot ... - Science Daily - February 9th, 2017 [February 9th, 2017]
- Bacteria sleep, then rapidly evolve, to survive antibiotic treatments - Phys.Org - February 9th, 2017 [February 9th, 2017]
- Orangutan squeaks reveal language evolution, says study - BBC ... - BBC News - February 9th, 2017 [February 9th, 2017]
- Evolution gives rhyme its reason - Aurora News Register - February 9th, 2017 [February 9th, 2017]
- Deeper origin of gill evolution suggests 'active lifestyle' link in early vertebrates - Science Daily - February 9th, 2017 [February 9th, 2017]
- From Tara Palmer-Tomkinson to Cara Delevingne: the evolution of the It girl - The Guardian - February 10th, 2017 [February 10th, 2017]
- Banned TED Talk: Rupert Sheldrake The Science Delusion - Collective Evolution - February 10th, 2017 [February 10th, 2017]
- VOTD: Watch the Evolution of Keanu Reeves' Acting Career - /FILM - February 10th, 2017 [February 10th, 2017]
- Pokmon Go Eevee evolution: How to evolve Eevee into Vaporeon, Jolteon and Flareon with new names - Eurogamer.net - February 10th, 2017 [February 10th, 2017]
- Horse evolution bucks evolutionary theory - Science News - February 10th, 2017 [February 10th, 2017]
- Samsung's Chromebook Pro highlights the category's continued evolution - TechCrunch - February 10th, 2017 [February 10th, 2017]
- Scientists solve fish evolution mystery - Phys.Org - February 10th, 2017 [February 10th, 2017]
- Wildfire evolution forces Forest Service into new thinking - The Daily Progress - February 11th, 2017 [February 11th, 2017]
- How the horse can help us answer one of evolution's biggest questions - Raw Story - February 11th, 2017 [February 11th, 2017]
- A primer on Darwin Day: Some religious groups embrace 'Theistic evolution' - LancasterOnline - February 11th, 2017 [February 11th, 2017]
- Apple: Evolution of in-car audio tech moving at 'speed of sound ... - Times of India - February 11th, 2017 [February 11th, 2017]
- Mariska Hargitay's Evolution from '80s Glam to Law & Order: Special Victims Unit - TVOvermind - February 12th, 2017 [February 12th, 2017]
- Evolution of baseball from power to speed has left SBs behind ... - Chicago Sun-Times - February 12th, 2017 [February 12th, 2017]
- More order with less judgment: An optimal theory of the evolution of cooperation - Science Daily - February 12th, 2017 [February 12th, 2017]
- J. Albert C. Uy speaks on evolution, biodiversity in bellied flycatcher population - The College Reporter - February 12th, 2017 [February 12th, 2017]
- See the Evolution of Movie Magic With Every Oscar Winner for Visual Effects in History - Gizmodo - February 12th, 2017 [February 12th, 2017]
- Numerology: Here's What Your Name Says About You - Collective Evolution - February 13th, 2017 [February 13th, 2017]
- The Evolution of Valentine's Day - Inside Science News Service - February 13th, 2017 [February 13th, 2017]
- Why evolution may be tech billionaires' biggest enemy - The Week Magazine - February 13th, 2017 [February 13th, 2017]
- Community Viewpoint: Evolution, like gravity, is much more than theory it is a fact - Kdminer - February 13th, 2017 [February 13th, 2017]
- How the horse can help us answer one of evolution's biggest questions - Phys.Org - February 13th, 2017 [February 13th, 2017]
- How evolution alters biological invasions - Science Daily - February 13th, 2017 [February 13th, 2017]
- Cockeyed squid shines light on deep sea evolution - Christian Science Monitor - February 13th, 2017 [February 13th, 2017]
- Eye Evolution: A Closer Look - Discovery Institute - February 14th, 2017 [February 14th, 2017]
- Evolution always wins: University of Idaho video game uses mutating aliens to teach science concepts - The Spokesman-Review - February 14th, 2017 [February 14th, 2017]
- Geneticists track the evolution of parenting - Phys.Org - February 14th, 2017 [February 14th, 2017]
- How this cockeyed squid shines a light on deep sea evolution - Christian Science Monitor - February 14th, 2017 [February 14th, 2017]
- 4 Possible Roadmaps For macOS and iOS Evolution - The Mac Observer (blog) - February 15th, 2017 [February 15th, 2017]
- The Evolution of the Energy Capital of the World - Texas Monthly - February 15th, 2017 [February 15th, 2017]
- Humons presents an atypical dance evolution - Detroit Metro Times - February 15th, 2017 [February 15th, 2017]
- Pokemon Go Adds 80 Generation 2 Pokemon, New Evolution Items This Week - IGN - February 15th, 2017 [February 15th, 2017]
- Fossil discovery rewrites understanding of reproductive evolution ... - Science Daily - February 15th, 2017 [February 15th, 2017]
- 'X-Men: Evolution' Is the Gateway Drug of Comic Book Shows - Geek - February 16th, 2017 [February 16th, 2017]
- A cultural catch: Evolution of wooden halibut hooks carved by native ... - Science Daily - February 16th, 2017 [February 16th, 2017]
- Bremerton's Fitness Evolution now Planet Fitness - Kitsap Sun (blog) - February 16th, 2017 [February 16th, 2017]
- Eye Evolution: The Waiting Is the Hardest Part - Discovery Institute - February 16th, 2017 [February 16th, 2017]
- Evolution Of The Yeezy: 2009-2017 - HotNewHipHop - February 16th, 2017 [February 16th, 2017]
- Prebiotic evolution: Hairpins help each other out - Science Daily - February 16th, 2017 [February 16th, 2017]
- This 'Live Birth' Fossil Could Change Humanity's Understanding Of Evolution - Daily Caller - February 16th, 2017 [February 16th, 2017]
- Mysterious Ancient Stonehenge-Like Circles Found in Amazon Rainforest - Collective Evolution - February 16th, 2017 [February 16th, 2017]
- 'Pokemon Go': How to Evolve Poliwhirl Into Politoed - Heavy.com - February 17th, 2017 [February 17th, 2017]
- 'Pokemon Go': How to Evolve Slowpoke Into Slowbro or Slowking - Heavy.com - February 17th, 2017 [February 17th, 2017]
- 'Pokemon Go': How to Evolve Gloom Into Bellossom - Heavy.com - February 17th, 2017 [February 17th, 2017]
- Pokmon Go Dragon Scale - how to evolve Seadra into Kingdra and how to get the Dragon Scale - Eurogamer.net - February 17th, 2017 [February 17th, 2017]
- Pokmon Go Eevee evolution: How to evolve Eevee into Umbreon, Espeon, Vaporeon, Jolteon and Flareon with new ... - Eurogamer.net - February 17th, 2017 [February 17th, 2017]
- University of Pittsburgh guest speaker discloses evolution findings - UTA The Shorthorn - February 17th, 2017 [February 17th, 2017]
- 'Pokemon Go' Special Items: Drop Rates for Evolution Items & Berries at Pokestops - Heavy.com - February 17th, 2017 [February 17th, 2017]
- How Vedic Philosophy Influenced Nikola Tesla's Idea of 'Free Energy' - Collective Evolution - February 18th, 2017 [February 18th, 2017]
- Migration to America took long enough for evolution to happen on the way - Ars Technica - February 18th, 2017 [February 18th, 2017]
- How To Choose Your Eevee Evolution In 'Pokmon GO:' Umbreon And Espeon Edition - Forbes - February 18th, 2017 [February 18th, 2017]
- Evolution Items - IGN - February 18th, 2017 [February 18th, 2017]
- Congo River fish evolution shaped by intense rapids: Genomic study ... - Science Daily - February 18th, 2017 [February 18th, 2017]
- Pokmon Go - How to evolve, use Special Items, when to evolve or Power Up your Pokmon - Eurogamer.net - February 18th, 2017 [February 18th, 2017]