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Dinosaurs would have continued to thrive had it not been for the asteroid, researchers say – CNN

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After emerging during the Triassic period some 230 million years ago, dinosaurs occupied every continent and were dominant in most terrestrial ecosystems, until they were rendered extinct by the asteroid impact 66 million years ago.
Some scientists believe the creatures were beginning to lose their edge and were already heading for extinction when the asteroid hit Earth at the end of the late Cretaceous period.
But researchers from the UK’s University of Bath are hoping to put this theory to bed. Gathering diverse and up-to-date data, researchers used statistical analysis to assess whether the dinosaurs were still able to produce new species up until their untimely demise.
An artist's interpretation of the asteroid impact that wiped out all non-avian dinosaurs
“What we found is that the dinosaurs were still dominant, they were still widespread and still doing really well,” Joe Bonsor, first author of the study, said in a statement.
“If the asteroid impact had never happened then they might not have died out and they would have continued after the Cretaceous,” Bonsor, a PhD student at London’s Natural History Museum and the Milner Centre for Evolution at the University of Bath, added.
During their more than 150 million years on earth, dinosaurs evolved to take many shapes and forms — some dinosaurs were tiny, while others measured over 100 feet. Experts think diversity was the key to their dominance on Earth, with some boasting armors, crests, teeth and even feathers.
Previous research had suggested that this diversity was starting to decline, and that dinosaurs were beginning to lose their dominance.
But the study published Tuesday in the journal The Royal Society Open Science argues that the earlier research reached this conclusion by modeling dinosaur family trees based on previous fossil records.
The University of Bath researchers say that, after looking at a greater number of dinosaur groups, their more up-to-date and detailed family trees show that dinosaurs on every continent were in fact flourishing, with plant-eating animals such as hadrosaurs, ceratopsians and ankylosaurs dominant in North America, and carnivorous abelisaurs continuing to thrive in South America.
“The main point of what we are saying is that we don’t really have enough data to know either way what would have happened to the dinosaurs,” Bonsor said. “Generally in the fossil record there is a bias towards a lack of data, and to interpret those gaps in the fossil record as an artificial decline in diversification rates isn’t what we should be doing.
“Instead we’ve shown that there is no strong evidence for them dying out, and that the only way to know for sure is to fill in the gaps in the fossil record,” he added.
Alfio Alessandro Chiarenza, a palaeontologist at Imperial College London, who was not involved in the research, told CNN in an email that the study “applies probably the largest dataset of dinosaur evolutionary trees ever and applies thorough methods to look at diversification rates towards the end of the Mesozoic.”
He noted that the research added weight to the argument that non-avian dinosaurs were thriving, not dwindling, before the asteroid hit.
“To paraphrase TS Eliot,” Chiarenza said, “This is the way dinosaurs ended, not with a whimper but with a bang.”

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Landmark wheat genome discovery could shore up global food security – New Food

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Project leader, Curtis Pozniak, compares the findings to locating a missing piece of your favourite puzzle, and hopes this will transform the way wheat is grown globally.

Scientists believe the genome sequencing will lead to higher wheat yields around the world.

An international team led by the University of Saskatchewan (USask) has sequenced the genomes for 15 wheat varieties representing breeding programmes around the world.

This landmark discovery will enable scientists and breeders to identify influential genes for improved yield, pest resistance and other important crop traits much more quickly.

The research results, published in Nature, provide what the research team has called the most comprehensive atlas of wheat genome sequences ever reported. The 10+ Genome Project collaboration involved more than 95 scientists from universities and institutes across Canada, Switzerland, Germany, Japan, the UK, Saudi Arabia, Mexico, Israel, Australia and the US.

“It’s like finding the missing pieces for your favourite puzzle that you have been working on for decades,” said project leader Curtis Pozniak, wheat breeder and director of the USask Crop Development Centre (CDC). “By having many complete gene assemblies available, we can now help solve the huge puzzle that is the massive wheat pan-genome and usher in a new era for wheat discovery and breeding.”

Scientific groups across the global wheat community are expected to use the new resource to identify genes linked to in-demand traits, such as pest and diseases resistance, which will accelerate breeding efficiency.

“This resource enables us to more precisely control breeding to increase the rate of wheat improvement for the benefit of farmers and consumers, and meet future food demands,” Pozniak added.

As one of the world’s most cultivated cereal crops, wheat plays an important role in global food security, providing about 20 percent of human caloric intake globally. The university says it’s estimated that wheat production must increase by more than 50 percent by 2050 to meet an increasing global demand – knowing which wheat genomes ‘best perform’ could be crucial in delivering this target.

The researchers explain that they were able to track the unique DNA signatures of genetic material incorporated into modern cultivars from several of wheat’s undomesticated relatives by breeders over the last century.1

“These wheat relatives have been used by breeders to improve disease resistance and stress resistance of wheat,” said Pozniak. “One of these relatives contributed a DNA segment to modern wheat that contains disease-resistant genes and provides protection against a number of fungal diseases. Our collaborators from Kansas State University and the International Maize and Wheat Improvement Center (CIMMYT) in Mexico, showed that this segment can improve yields by as much as 10 percent. Since breeding is a continual improvement process, we can continue to cross plants to select for this valuable trait.”

Pozniak’s team, in collaboration with scientists from Agriculture and Agri-Food Canada, and National Research Council of Canada, also used the genome sequences to isolate an insect-resistant gene (Sm1). This gene enables wheat plants to withstand the orange wheat blossom midge, a pest which can cause more than $60 million in annual losses to Western Canadian producers.1

“Understanding a causal gene like this is a game-changer for breeding because you can select for pest resistance more efficiently by using a simple DNA test than by manual field testing,” Pozniak concluded.

References 

  1. www.nature.com/articles/s41586-020-2961-x 

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T. rex got huge via major teenage growth spurt – CBC.ca

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Large meat-eating dinosaurs attained their great size through very different growth strategies, with some taking a slow and steady path and others experiencing an adolescent growth spurt, according to scientists who analyzed slices of fossilized bones.

The researchers examined the annual growth rings — akin to those in tree trunks — in bones from 11 species of theropods, a broad group spanning all the big carnivorous dinosaurs including Tyrannosaurus rex and even birds. The study provides insight into the lives of some of the most fearsome predators ever to walk the Earth.

The team looked at samples from museums in the United States, Canada, China and Argentina and even received clearance to cut into bones from one of the world’s most famous T. rex fossils, known as Sue and housed at the Field Museum in Chicago, using a diamond-tipped saw and drill.

Sue’s leg bones — a huge femur and fibula — helped illustrate that T. rex and its relatives — known as tyrannosaurs — experienced a period of extreme growth during adolescence and reached full adult size by around age 20. Sue, measuring about 13 metres, lived around 33 years.

Sue inhabited South Dakota about a million years before dinosaurs and many other species were wiped out by an asteroid impact 66 million years ago.

Other groups of large theropods tended to have more steady rates of growth over a longer period of time. That growth strategy was detected in lineages that arose worldwide earlier in the dinosaur era and later were concentrated in the southern continents.

Examples included Allosaurus and Acrocanthosaurus from North America, Cryolophosaurus from Antarctica and a recently discovered as-yet-unnamed species from Argentina that rivaled T. rex in size. The Argentine dinosaur, from a group called carcharodontosaurs, did not reach its full adult size until its 40s and lived to about age 50.

Big theropods share the same general body design, walking on two legs and boasting large skulls, strong jaws and menacing teeth.

“Prior to our study, it was known that T. rex grew very quickly, but it was not clear if all theropod dinosaurs reached gigantic size in the same way, or if there were multiple ways it was done,” said paleontologist and study lead author Tom Cullen of the North Carolina Museum of Natural Sciences and North Carolina State University, also affiliated with the Field Museum.

The research was published this week in the journal Proceedings of the Royal Society B.

“Theropod dinosaurs represent the largest bipedal animals to have ever lived and were also the dominant predators in terrestrial ecosystems for over 150 million years — more than twice as long as mammals have been dominant,” added University of Minnesota paleontologist and study co-author Peter Makovicky

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Slow and steady or a big spurt? How to grow a ferocious dinosaur – Cape Breton Post

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By Will Dunham

WASHINGTON (Reuters) – Large meat-eating dinosaurs attained their great size through very different growth strategies, with some taking a slow and steady path and others experiencing an adolescent growth spurt, according to scientists who analyzed slices of fossilized bones.

The researchers examined the annual growth rings – akin to those in tree trunks – in bones from 11 species of theropods, a broad group spanning all the big carnivorous dinosaurs including Tyrannosaurus rex and even birds. The study provides insight into the lives of some of the most fearsome predators ever to walk the Earth.

The team looked at samples from museums in the United States, Canada, China and Argentina and even received clearance to cut into bones from one of the world’s most famous T. rex fossils, known as Sue and housed at the Field Museum in Chicago, using a diamond-tipped saw and drill.

Sue’s leg bones – a huge femur and fibula – helped illustrate that T. rex and its relatives – known as tyrannosaurs – experienced a period of extreme growth during adolescence and reached full adult size by around age 20. Sue, measuring about 42 feet (13 metres), lived around 33 years.

Sue inhabited South Dakota about a million years before dinosaurs and many other species were wiped out by an asteroid impact 66 million years ago.

Other groups of large theropods tended to have more steady rates of growth over a longer period of time. That growth strategy was detected in lineages that arose worldwide earlier in the dinosaur era and later were concentrated in the southern continents.

Examples included Allosaurus and Acrocanthosaurus from North America, Cryolophosaurus from Antarctica and a recently discovered as-yet-unnamed species from Argentina that rivaled T. rex in size. The Argentine dinosaur, from a group called carcharodontosaurs, did not reach its full adult size until its 40s and lived to about age 50.

Big theropods share the same general body design, walking on two legs and boasting large skulls, strong jaws and menacing

teeth.

“Prior to our study, it was known that T. rex grew very quickly, but it was not clear if all theropod dinosaurs reached gigantic size in the same way, or if there were multiple ways it was done,” said paleontologist and study lead author Tom Cullen of the North Carolina Museum of Natural Sciences and North Carolina State University, also affiliated with the Field Museum.

The research was published this week in the journal Proceedings of the Royal Society B.

“Theropod dinosaurs represent the largest bipedal animals to have ever lived and were also the dominant predators in terrestrial ecosystems for over 150 million years – more than twice as long as mammals have been dominant,” added University of Minnesota paleontologist and study co-author Peter Makovicky.

(Reporting by Will Dunham; Editing by Peter Cooney)

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