Ancient sea creatures filtered food like modern whales

Ancient, giant marine animals used bizarre facial appendages to filter food from the ocean, according to new fossils discovered in northern Greenland. The new study, led by the University of Bristol and published today in Nature, describes how the strange species, called Tamisiocaris, used these huge, specialized appendages to filter plankton, similar to the way modern blue whales feed today.The animals lived 520 million years ago during the Early Cambrian, a period known as the ‘Cambrian Explosion’ in which all the major animal groups and complex ecosystems suddenly appeared. Tamisiocaris belongs to a group of animals called anomalocarids, a type of early arthropod that included the largest and some of the most iconic animals of the Cambrian period. They swam using flaps down either side of the body and had large appendages in front of their mouths that they most likely used to capture larger prey, such as trilobites.However, the newly discovered fossils show that those predators also evolved into suspension feeders, their grasping appendages morphing into a filtering apparatus that could be swept like a net through the water, trapping small crustaceans and other organisms as small as half a millimetre in size.The evolutionary trend that led from large, apex predators to gentle, suspension-feeding giants during the highly productive Cambrian period is one that has also taken place several other times throughout Earth’s history, according to lead author Dr Jakob Vinther, a lecturer in macroevolution at the University of Bristol.Dr Vinther said: “These primitive arthropods were, ecologically speaking, the sharks and whales of the Cambrian era. In both sharks and whales, some species evolved into suspension feeders and became gigantic, slow-moving animals that in turn fed on the smallest animals in the water.”In order to fully understand how the Tamisiocaris might have fed, the researchers created a 3D computer animation of the feeding appendage to explore the range of movements it could have made.”Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth,” said Dr Martin Stein of the University of Copenhagen, who created the computer animation. “This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence.”The discovery also helps highlight just how productive the Cambrian period was, showing how vastly different species of anomalocaridids evolved at that time, and provides further insight into the ecosystems that existed hundreds of millions of years ago.”The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem,” Dr Vinther said. “Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy — and therefore lots of food.”Tamisiocaris is one of many recent discoveries of remarkably diverse anomalocarids found in rocks aged 520 to 480 million years old. “We once thought that anomalocarids were a weird, failed experiment,” said co-author Dr Nicholas Longrich at the University of Bath. “Now we’re finding that they pulled off a major evolutionary explosion, doing everything from acting as top predators to feeding on tiny plankton.”The Tamisiocaris fossils were discovered during a series of recent expeditions led by co-author David Harper, a professor at Durham University. “The expeditions have unearthed a real treasure trove of new fossils in one of the remotest parts of the planet, and there are many new fossil animals still waiting to be described,” he said. …

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Overeating learned in infancy, study suggests

May 22, 2013 — In the long run, encouraging a baby to finish the last ounce in their bottle might be doing more harm than good. Though the calories soon burn off, a bad habit remains.

Brigham Young University sociology professors Ben Gibbs and Renata Forste found that clinical obesity at 24 months of age strongly traces back to infant feeding.

“If you are overweight at age two, it puts you on a trajectory where you are likely to be overweight into middle childhood and adolescence and as an adult,” said Forste. “That’s a big concern.”

The BYU researchers analyzed data from more than 8,000 families and found that babies predominantly fed formula were 2.5 times more likely to become obese toddlers than babies who were breastfed for the first six months.

But, the study authors argue, this pattern is not just about breastfeeding.

“There seems to be this cluster of infant feeding patterns that promote childhood obesity,” said Gibbs, lead author of the study that appears in Pediatric Obesity.

Putting babies to bed with a bottle increased the risk of childhood obesity by 36 percent. And introducing solid foods too soon — before four months of age — increased a child’s risk of obesity by 40 percent.

“Developing this pattern of needing to eat before you go to sleep, those kinds of things discourage children from monitoring their own eating patterns so they can self-regulate,” Forste said.

Forste said that the nature of breastfeeding lends itself to helping babies recognize when they feel full and should stop. But that same kind of skill can be developed by formula-fed infants.

“You can still do things even if you are bottle feeding to help your child learn to regulate their eating practices and develop healthy patterns,” Forste said. “When a child is full and pushes away, stop! Don’t encourage them to finish the whole bottle.”

Breastfeeding rates are lowest in poor and less educated families. Sally Findley, a public health professor at Columbia University, says the new BYU study shows that infant feeding practices are the primary reason that childhood obesity hits hardest below the poverty line.

“Bottle feeding somehow changes the feeding dynamic, and those who bottle feed, alone or mixed with some breastfeeding, are more likely to add cereal or sweeteners to their infant’s bottle at an early age, even before feeding cereal with a spoon,” said Findley.

The next project for Gibbs and Forste is to reevaluate the link between breastfeeding and cognitive development in childhood. Forste has previously published research about why women stop breastfeeding.

“The health community is looking to the origins of the obesity epidemic, and more and more, scholars are looking toward early childhood,” Gibbs said. “I don’t think this is some nascent, unimportant time period. It’s very critical.”

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