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Sea Creatures Are Getting Bigger

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While some animals—like dragonflies and penguins—have gotten smaller over time, sea creatures seem to be getting bigger. 

This news may not be particularly shocking—after all, living creatures started out as microscopic, and have evolved into things like the blue whale, currently the largest creature on Earth. Sure, it took a couple billion years to make that progress, but it happened. 

The idea that animals are always getting bigger is known as Cope's rule. Named after paleontologist Edward Drinker Cope, the rule suggests that animal lineages increase in body size over time. The hypothesis is based off the scientist's observations after looking at various fossils. The rule has been tested and documented for over a century, but a recent report published by Science provides the most convincing evidence yet.

A team led by Stanford University's Noel Heim analyzed more than 17,000 fossils of various marine animals, some as old as 542 million years. The study found that marine animals were, on average, 150 times larger than their Cambrian era counterparts.

"That's the size difference between a sea urchin that is about 2 inches long versus one that is nearly a foot long," said Noel Heim, a postdoctoral researcher in Payne's lab. "This may not seem like a lot, but it represents a big jump."

What's interesting is that not all the animals are getting bigger; this trend is being driven by larger animals surviving and diversifying to create more species.

"That's also something we didn't know before. For reasons that we don't completely understand, the classes with large body size appear to be the ones that over time have become differentially more diverse," said Jonathan Payne, a paleobiologist at Stanford School of Earth, Energy & Environmental Sciences.

The data leads scientists to believe that larger animals are evolutionarily favored, as there are many advantages to being greater in size. Larger size makes for a more formidable opponent, that can swim faster, burrow deeper, and eat larger prey. 

"As time marches forward, each species is assigned some probability of producing a new species, of remaining the same, or of going extinct, at which point it drops out of the race," Heim said.

The study will hopefully encourage other scientists to look for other trends in evolution. If size is a clear driving force, then perhaps evolution moves in other directional ways.

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Animals
How Bats Protect Rare Books at This Portuguese Library
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Visit the Joanina Library at the University of Coimbra in Portugal at night and you might think the building has a bat problem. It's true that common pipistrelle bats live there, occupying the space behind the bookshelves by day and swooping beneath the arched ceilings and in and out of windows once the sun goes down, but they're not a problem. As Smithsonian reports, the bats play a vital role in preserving the institution's manuscripts, so librarians are in no hurry to get rid of them.

The bats that live in the library don't damage the books and, because they're nocturnal, they usually don't bother the human guests. The much bigger danger to the collection is the insect population. Many bug species are known to gnaw on paper, which could be disastrous for the library's rare items that date from before the 19th century. The bats act as a natural form of pest control: At night, they feast on the insects that would otherwise feast on library books.

The Joanina Library is famous for being one of the most architecturally stunning libraries on earth. It was constructed before 1725, but when exactly the bats arrived is unknown. Librarians can say for sure they've been flapping around the halls since at least the 1800s.

Though bats have no reason to go after the materials, there is one threat they pose to the interior: falling feces. Librarians protect against this by covering their 18th-century tables with fabric made from animal skin at night and cleaning the floors of guano every morning.

[h/t Smithsonian]

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Honey Bees Can Understand the Concept of Zero
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The concept of zero—less than one, nothing, nada—is deceptively complex. The first placeholder zero dates back to around 300 BCE, and the notion didn’t make its way to Western Europe until the 12th century. It takes children until preschool to wrap their brains around the concept. But scientists in Australia recently discovered a new animal capable of understanding zero: the honey bee. According to Vox, a new study finds that the insects can be taught the concept of nothing.

A few other animals can understand zero, according to current research. Dolphins, parrots, and monkeys can all understand the difference between something and nothing, but honey bees are the first insects proven to be able to do it.

The new study, published in the journal Science, finds that honey bees can rank quantities based on “greater than” and “less than,” and can understand that nothing is less than one.

Left: A photo of a bee choosing between images with black dots on them. Right: an illustration of a bee choosing the image with fewer dots
© Scarlett Howard & Aurore Avarguès-Weber

The researchers trained bees to identify images in the lab that showed the fewest number of elements (in this case, dots). If they chose the image with the fewest circles from a set, they received sweetened water, whereas if they chose another image, they received bitter quinine.

Once the insects got that concept down, the researchers introduced another challenge: The bees had to choose between a blank image and one with dots on it. More than 60 percent of the time, the insects were successfully able to extrapolate that if they needed to choose the fewest dots between an image with a few dots and an image with no dots at all, no dots was the correct answer. They could grasp the concept that nothing can still be a numerical quantity.

It’s not entirely surprising that bees are capable of such feats of intelligence. We already know that they can count, teach each other skills, communicate via the “waggle dance,” and think abstractly. This is just more evidence that bees are strikingly intelligent creatures, despite the fact that their insect brains look nothing like our own.

Considering how far apart bees and primates are on the evolutionary tree, and how different their brains are from ours—they have fewer than 1 million neurons, while we have about 86 billion—this finding raises a lot of new questions about the neural basis of understanding numbers, and will no doubt lead to further research on how the brain processes concepts like zero.

[h/t Vox]

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