Tag: evolved

Pine needles evolved to help trees cope with rainfall

Sept. 29 (UPI) — The needles of longleaf pine trees evolved to effectively shed water, according to a study published Tuesday in the journal Physics of Fluids, ensuring rain moistens the soil instead of clogging leaf pores.

“Our initial inspiration for this project was [to study] raindrop impact on pine trees,” Andrew Dickerson, professor of engineering at University of Central Florida, told UPI in an email.

Dickerson and his research partners wanted to find whether or not rainfall has influenced the material properties of pine needles.

“We began impact drops onto cantilevered needles, but quickly realized the physics was very complicated and that the simpler problem of drop impact onto fixed, non-circular fibers had not yet been tackled,” Dickerson said.

To tackle it, researchers set up high-speed cameras to capture high-resolution, slow-motion video of drops hitting the wedge-shaped needles of longleaf pines.

According to Dickerson, dozens of studies have looked

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Fossil upends theory of how shark skeletons evolved, say scientists

a fish swimming under water: Photograph: Ullstein Bild/Getty Images

© Provided by The Guardian
Photograph: Ullstein Bild/Getty Images

The partial skull of an armoured fish that swam in the oceans over 400m years ago could turn the evolutionary history of sharks on its head, researchers have said.

Bony fish, such as salmon and tuna, as well as almost all terrestrial vertebrates, from birds to humans, have skeletons that end up made of bone. However, the skeletons of sharks are made from a softer material called cartilage – even in adults.

Researchers have long explained the difference by suggesting the last common ancestor of all jawed vertebrates had an internal skeleton of cartilage, with bony skeletons emerging after sharks had already evolved. The development was thought so important, living vertebrates are divided into “bony vertebrates” and “cartilaginous vertebrates” as a result.

a fish swimming under water: Galapagos sharks off the coast of Hawaii. The skeletons of sharks are made from cartilage rather than bone but new evidence suggests they could have bony ancestors.

© Photograph: Ullstein Bild/Getty Images
Galapagos sharks off the coast of Hawaii. The skeletons of sharks are made from

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