Grad student proves one of Darwin's theories almost 140 years after his death

In On the Origin of Species, Charles Darwin posited that animal lineages with more species should also have more sub-species, or "varieties" in Darwin's terminology. Now, nearly 140 years after Darwin's death, Laura van Holstein, a PhD student in Biological Anthropology at the University of Cambridge, and her colleagues have proven Darwin right. According to a University of Cambridge report, "her research could now be used to predict which species conservationists should focus on protecting to stop them becoming endangered or extinct":

A species is a group of animals that can interbreed freely amongst themselves. Some species contain subspecies – populations within a species that differ from each other by having different physical traits and their own breeding ranges. Northern giraffes have three subspecies that usually live in different locations to each other and red foxes have the most subspecies – 45 known varieties – spread all over the world. Humans have no subspecies.

van Holstein said: “We are standing on the shoulders of giants... My research investigating the relationship between species and the variety of subspecies proves that sub-species play a critical role in long-term evolutionary dynamics and in future evolution of species. And they always have, which is what Darwin suspected when he was defining what a species actually was.”

van Holstein’s research also proved that evolution happens differently in land mammals (terrestrial) and sea mammals and bats (non-terrestrial)­ because of differences in their habitats and differences in their ability to roam freely.

Here is the scientific paper: "Terrestrial habitats decouple the relationship between species and subspecies diversification in mammals" (The Royal Society)

image credit: Nordin Ćatić, University of Cambridge news release Read the rest

This newly discovered cannabis compound is possibly 30 times more powerful than THC

Researchers identified a phytocannabinoid in Cannabis sativa that they say could be 30 times more powerful than THC, at least in their lab results. The scientists from Italy's University of Modena and Reggio Emilia and their colleagues found that in their in vitro tests, tetrahydrocannabiphorol (THCP) showed an attraction to the nervous system's cannabinoid (CB1) receptor that's more than thirty times higher than good ol' THC. From CNN:

CBD has mostly been the focus of studies on the health benefits of cannabis, but because THCP appears to show stronger binding abilities and potency, the authors think there is potential for health benefits.

The findings could enable the production of cannabis extracts for targeted physical effects; more testing with the study's methods could further the discovery and identification of new compounds, the authors said.

"There are other minor cannabinoids and traces in the plant that can be hard to study, but by isolation we can continue to assess the effects they might offer," (said Jane Ishmael, associate professor in Oregon State University's College of Pharmacy, who was not involved in the research.

"Historically, many of our medicines have been derived by or inspired by natural products. By having new compounds that bind with very high affinity, that will give scientists a new probe into biological sciences."

Read the scientific paper: "A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than Δ9-tetrahydrocannabinol: Δ9-Tetrahydrocannabiphorol" (Nature Scientific Reports)

image: Thayne Tuason (CC BY-SA 4.0 Read the rest

Incredible microscope video of an otherworldly green algae colony

First discovered in 1700 by Antonie van Leeuwenhoek, the microscopic spheres in this video are Volvox, a genus of chlorophyte green algae. If you enjoy this video, its creator Shigeru Gougi posts absolutely astounding microscopy images on his Flickr stream. Want to explore the Volvox realm yourself? From Microbehunter Microscopy:

Microscopists who are interested in observing Volvox should try to investigate water samples from ponds and puddles. It is also possible to grow Volvox at home. Volvox likes to grow in nutrient-rich water. Dilute some plant fertilizer in water and add some pond water containing Volvox (or other green algae that you want to grow). Place the container on the window sill for several days but prevent direct sunlight as this may cause overheating, and drives out the CO2 for photosynthesis from the water. Alternatively, you can also use a plankton net to catch the colonies.

Learn more at The Kid Should See This. Read the rest

How cows use their unique voices to cowmoooonicate

For five months, University of Sydney PhD student Alexandra Green spent time in the field, literally, with 18 Holstein-Friesian heifers, recording and studying their sounds. While it's been known that cow moms and calves use unique vocalizations with one another, Green confirmed that cattle "also maintain individual voices in a variety of emotional situations," from chow time to periods when they are isolated from the others in the herd. From the University of Sydney:

Cows ‘talk’ to one another and retain individual identity through their lowing...

The conclusion of the research is that farmers should integrate knowledge of individual cow voices into their daily farming practices.

“We found that cattle vocal individuality is relatively stable across different emotionally loaded farming contexts,” Ms Green said...

“We hope that through gaining knowledge of these vocalisations, farmers will be able to tune into the emotional state of their cattle, improving animal welfare,” Ms Green said.

"Vocal individuality of Holstein-Friesian cattle is maintained across putatively positive and negative farming contexts" (Scientific Reports via Atlas Obscura)

image: Lynne Gardner/University of Sydney

(Thanks to University of Sydney for inspiring the headline!)

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Sex pheromone named after a character in Jane Austen's "Pride and Prejudice" changes mice brains

Darcin is a pheromone found in the urine of male mice. It's used to mark territory and signal mating availability, and was named after the character Mr. Darcy who appears in Jane Austin's Pride and Prejudice. In the new issue of Nature, researchers at Columbia University report on how darcin "takes hold in the brains of female mice, giving cells in the brain's emotion center the power to assess the mouse's sexual readiness and help her select a mate."

From the press release:

Pheromones, such as darcin, are processed somewhat differently. They interact with a second, parallel olfactory system, which exists in animals like mice but not in people.

"Unlike people, mice have essentially two functional noses," said Dr. Demir. "The first nose works like ours: processing scents such as the stinky odor particles found in urine. But a second system, called the vomernasal nose, evolved specifically to perceive pheromones like darcin."

For today's study, the research team, which also included Dr. Hurst, Dr. Beynon and co-senior author Adam Kepecs, PhD, of Cold Spring Harbor Laboratory, first exposed female mice to darcin-scented urine and monitored their behavior. Nearly all of the female mice showed an immediate attraction to darcin. Then, after about 50 minutes, some females began leaving their own urinary scent markings. They also started to sing, at ultrasonic frequencies too high for the human ear to hear. Both of these behaviors are an indicator of increased sexual drive.

Image by Rama - Own work, CC BY-SA 2.0 Read the rest

Watch a tsetse fly birth a shockingly big larva. Gross! Amazing!

And you thought you felt full. Check out this female tsetse fly push out a larva fat with its momma's milk. From Deep Look:

Mammalian moms aren’t the only ones to deliver babies and feed them milk. Tsetse flies, the insects best known for transmitting sleeping sickness, do it too.

(UC Davis medical entomologist Geoff Attardo) is trying to understand in detail the unusual way in which these flies reproduce in order to find new ways to combat the disease, which has a crippling effect on a huge swath of Africa.

When it’s time to give birth, a female tsetse fly takes less than a minute to push out a squiggly yellowish larva almost as big as itself...

“There’s too much coming out of it to be able to fit inside,” (Attardo) recalled thinking. “The fact that they can do it eight times in their lifetime is kind of amazing to me.”

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Newly discovered sharks that walk are the "youngest" shark species on Earth

Some species of sharks have evolved to literally walk along the ocean floor (no, not on land) using their fins as feet. New research Conservation International’s Mark Erdmann and colleagues determined that walking sharks only evolved their unique capability 9 million years ago, "making them the 'youngest' sharks on our planet." Of course, a distinct species usually forms when some members of a species are physically separated from others. So how did that speciation occur in the case of the walking sharks? From an interview with Erdmann at Conservation International:

For most of the walking shark species, our findings support the idea that speciation occurred because the populations slowly expanded their range by walking or swimming, then some individuals eventually became isolated by environmental factors such as sea level rise or the formation of large river systems that broke up their habitats.

For the four walking shark species found at the Bird’s Head Seascape, we suspect that they actually hitched a ride — on a drifting island...

Q: Is there another mystery about walking sharks you hope to solve?

From a scientific perspective, there is still so much to learn from walking sharks. We know that the world’s species that exist today are basically the existing “genetic reservoir” (raw genetic material) we have to adapt to global changes. We also know that walking sharks are very resilient to warm water and that they have a tolerance for oxygen deprivation. Any time you have an animal or plant that can survive in these extreme conditions, there is typically something unique about their genes — a “special sauce”.

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Interactive online tour of Antarctica's microworld from science hacker Ariel Waldman

BB contributor and DIY science hacker Ariel Waldman recently went on a research expedition to Antarctica to study microscopic extremophiles under the ice. She made a great video series about it and has now created a wonderful interactive tour of this hidden world called "Life Under the Ice." It's damn cool. (Get it? Get it?!) From Ariel's project description:

Typically when we think about Antarctica, we think of a place that's barren and lifeless... except for a few penguins. But Antarctica should instead be known as a polar oasis of life, host to countless creatures that are utterly fascinating. They’ve just been invisible to us – until now. Life Under the Ice enables anyone to delve into the microscopic world of Antarctica as an explorer; as if you had been shrunk down and were wading through one large petri dish of curiosities...

The collected Antarctic microbes were found living within glaciers, under the sea ice, next to frozen lakes, and in subglacial ponds. Microbes from under the sea ice were discovered in the Southern Ocean’s McMurdo Sound near McMurdo Station and the Erebus Glacier Tongue. Microbes from glaciers and frozen lakes were discovered in the McMurdo Dry Valleys at Lake Bonney and Lake Hoare.

Life Under the Ice Read the rest

Anne Dagg, pioneering giraffe biologist and feminist critic of "evolutionary psychology" receives the Order of Canada

Anne Innis Dagg was the first female biologist to study giraffes; while all the men who preceded her had observed firsthand that male giraffes are super queer (their primary form of play is a game dubbed "penis fencing," which is exactly what it sounds like), only Dagg was willing to write it down and publish it. Read the rest

Sequencing an anciet girl's genome from a 5,700-year-old piece of chewing gum

Almost 6,000 years ago on the island of Lolland, Denmark, a young girl disposed of her chewing gum. Now, University of Copenhagen researchers have used that gum, made from birch pitch, to sequence the girl's full genome. From Science:

The child had black hair, blue eyes, and dark skin, and was more closely related to hunter-gatherers from Western Europe than to farmers who had more recently settled in the region. She left traces of her most recent meal in the gum—she had been chewing hazelnuts and duck. But her oral microbiome also revealed that life could be hard—she had the Epstein-Barr virus and probably had suffered from mononucleosis in her life.

More in the scientific paper: "A 5700 year-old human genome and oral microbiome from chewed birch pitch" (Nature Communications) Read the rest

Check out this 480 million-year-old conga line of arthropods

When I was little, my big brother would take me fossil-hunting on a quest for trilobites, marine arthropods that have been extinct for around 250 million years. Occasionally we'd find lone specimens but never a bunch of them in a conga line as seen above. Paleontologists at France's Université Claude Bernard Lyon 1 studied lines of nearly two dozen trilobytes from Moroccan fossil beds to gain insight into the origins of collective social behavior. From the New York Times:

These trilobites lived during the Great Ordovician Biodiversification Event, a period defined by a dramatic increase in the variety and complexity of marine life. It was the evolutionary sequel to the first major diversification event, the so-called Cambrian explosion, which established most animal groups in the fossil record some 541 million years ago.

Before the Cambrian, there is “no evidence for group behavior” in animals, (paleontologist Jean) Vannier said, because Precambrian life-forms lacked sophisticated nervous systems.

Ampyx trilobites, in contrast, had an anatomy that could have enabled chemical communication and sensory stimulation. Though they were visually blind, the trilobites had long spikes protruding from their rear ends. These appendages clearly overlap and link individuals in the fossilized chains, and perhaps allowed tactile or pheromone signals to be exchanged.

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An unintended consequence of New York's new clean water is a return of destructive marine borers

"Shipworms" are a menace, devouring the wood in ships and docks. For a while, as the New York Times explains, the pollution in New York harbor actually had some benefit in fighting them:

By the 1960s, the waters had become overrun with raw sewage and oil and chemicals discharged by factories. “Industries were using the harbor as a dumping ground,” Mr. Goldstein said. “You wouldn’t want to swim or eat the fish, and only the bravest would take out a kayak.”

Indeed, there were stories of boats being taken into the polluted harbor just to clean off any marine borers from other waters.

The good news is New York waterways are increasingly clean thanks to laws like the the 1972 Clean Water Act. But the bad news is the clean water has allowed marine borers to flourish:

Marine borers took out a heavily used Brooklyn footbridge over Sheepshead Bay in 2015, requiring the city to close it for several months to repair a hole-ridden foundation. The borers have also weakened timber pilings under the Carroll Street Bridge over the Gowanus Canal in Brooklyn, and under the F.D.R. Drive in Manhattan.

Along the New Jersey waterfront their handiwork led most notably to the partial collapse of a pier at Frank Sinatra Park in Hoboken.

Now the city is spending massive amounts to fight the pests, including $114 million to coat the 11,000 timber pilings under Brooklyn Bridge Park with epoxy.

(Image of Teredo navalis from Popular Science Monthly, September 1878 and Wikipedia.) Read the rest

Adding pink seaweed to cow feed eliminates their methane emissions

One of the major contributors to greenhouse gases is the methane that cows belch up as they break down cellulose, but five years ago, research from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) found that adding small amounts of a pink seaweed called Asparagopsis to cows' diets eliminated the gut microbes responsible for methane production and "completely knocks out" cows' methane emissions. Read the rest

A deep dive into how parasites hijack our behavior and how we evolved to resist them

On Slate Star Codex (previously), Scott Alexander breaks down Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation, Marco Del Giudice's Quarterly Review of Biology paper that examines the measures that parasites take to influence their hosts' behaviors, and the countermeasures that hosts evolve to combat them. Read the rest

Find awe in the biology of these incredible leaping maggots

Above is a three-millimeter long maggot launching itself into the air for a distance of up to 36 times its body length. Researchers from Duke University and their colleagues studied how these larvae of gall midges leap between plants with the greatest of ease, even rivaling some jumping insects with legs. Their research could have applications in soft robotics and adhesives. From the Journal of Experimental Biology:

They store elastic energy by forming their body into a loop and pressurizing part of their body to form a transient ‘leg’. They prevent movement during elastic loading by placing two regions covered with microstructures against each other, which likely serve as a newly described adhesive latch. Once the latch releases, the transient ‘leg’ launches the body into the air. These discoveries integrate three vibrant areas in engineering and biology – soft robotics, small, high-acceleration systems, and adhesive systems – and point toward a rich, and as-yet untapped area of biological diversity of worm-like, small, legless jumpers.

(via Scientific American)

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Delightful deepsea encounter with a wildly cute and weird piglet squid

This darling denizen of the deep is a Helicocranchia, aka a piglet squid. Scientists on the Ocean Exploration Trust's E/V Nautilus caught footage of the rarely seen creature at a depth of 4,544 feet near Palmyra Atoll in the Northern Pacific Ocean. The commenters' delightful descriptions really make the clip.

(MNN via Kottke) Read the rest

Snail slime inspires new super-strong reversible glue

Snail slime -- called an epiphragm -- is an incredibly strong yet reversible adhesive. Now, University of Pennsylvania scientists have developed a new kind of glue that employs the same mechanism as the epiphragm. The new material dries like superglue but once wet, it loses its adhesion. For years, scientists have explored adhesions inspired by nature but none have been demonstrated to have the same amount of strength and reversibility. For example, the researchers report that their new adhesive "is 89 times stronger than gecko adhesion." From the University of Pennsylvania:

The breakthrough came one day when Gaoxiang Wu was working on another project that involved a hydrogel made of a polymer called polyhydroxyethylmethacrylate (PHEMA) and noticed its unusual adhesive properties. PHEMA is rubbery when wet but rigid when dry, a quality that makes it useful for contact lenses but also, as Yang's team discovered, for adhesives.

When PHEMA is wet, it conforms to all of the small grooves on a surface, from a tree trunk's distinct ridges to the invisible microporosity of a seemingly smooth wall. This conformal contact is what allows PHEMA to stick to a surface.

To demonstrate just how durable their PHEMA adhesive is, one of Yang's lab members and co-first author, Jason Christopher Jolly, volunteered to suspend himself from a harness held up only by a postage-stamp-sized patch of their adhesive; the material easily held the weight of an entire human body. Based on the lab tests, the team determined that, although PHEMA may not be the strongest adhesive in existence, it is currently the strongest known candidate available for reversible adhesion.

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