science-junkie:

Gene survival and death on the human Y chromosome
By M. Wilson Sayres

In humans, genetic females have two X chromosomes and genetic males have one X chromosome and one Y chromosome:
You might have noticed from the cartoon above that the human Y is much smaller than the human X. But, it wasn’t always this way. Ancestrally, the human X and Y were the same size, and had the same genes. Over time, however, the Y has shrunk, but both the X and Y have also gained some genes. To better understand how the X and Y became so different, and how the evolution of the two sex chromosomes are correlated, we asked three main questions:

What has been lost from the Y?
To know which genes were lost, we first had to identify which genes were on the ancestral sex chromosome pair. By comparing the genes on the human X with the genes the X in other species, we identified a set of genes that were likely on the ancestral X chromosome: 600 in total. Then, by searching the Y chromosome for the relics of all of these genes, we identified three classes of sex-linked genes. We should think of each of the 600 ancestral genes as a pair (with one copy on the X, and one on the Y). All of these pairs have a working copy on the human X. Some pairs have a working (functional) copy on the Y, some have a broken copy on the Y (degraded), and some are missing their Y-copy.

Many genes have been lost from the ancestral Y, but a few persist. So, while some Y-linked genes have survived (I have another paper discussing this), and there have been some unique additions to the Y chromosome, we can see that the Y has lost functional capabilities for 96.83% of the genes that it once shared with the X. Wow!

Are there indicators of whether a Y-linked gene will be retained?
We can learn about the evolution of the sex chromosomes by studying differences between classes of sex-linked genes defined above. Specifically we asked, do features of X-linked genes suggest whether their Y-linked partner are retained or lost? In some cases, yes, they do.

First, we found that human X-linked genes with very few changes across mammals were more likely to have a working Y copy. So, if a gene is important enough to survive over long evolutionary time in roughly the same condition across very different species, then it might be very useful to the organism, so it would be important to have that gene in a working form in both males and females in the same species (human).

Second, we looked at expression. Genes can sometimes be “on” (which we would call expressed) or “off” (not expressed), but more often they can fall within a range. It’s like a light with a dimmer switch. The light can be turned on very brightly, but can also dimmed to a very low level without being “off”.  We found that X-linked genes that were highly expressed (bright) were more likely to have a working Y copy. This might mean that, for these genes, the level of “brightness” or expression is important, so that it is highly beneficial for these genes to be working very hard in both females and in males.

Does gene loss on the Y affect the evolution the X?
Okay, so some features of the X-linked partner might predict whether it’s Y-linked partner will survive, but is there any feedback from the Y back to the X chromosome? Yes!

Let’s think back to that first picture: females have two “big” X chromosomes, while males have one “big” X and one “little” Y. And, I’ve shown you that the Y chromosome has lost (either because of broken copies, or completely lost) almost 97% of the genes that it once shared with the X. This might lead you to believe that there are more genes expressed in females than in males. But, in many mammals, females silence most of the genes on one of their X chromosomes (X-inactivation), to equalize the dosage of genes expressed between males and females.

Although it has been hypothesized, we showed that the pattern of genes subject to silencing in females among the three classes above is consistent with a process whereby silencing evolves in response to gene loss on the Y chromosome. Moreover, this pattern suggests that some amount of time must pass to allow the signal (that the Y-linked partner is no longer working) to reach the X-chromosome before silencing can occur.

The paper is open access, so if you are curious, you can read it on Molecular Biology and Evolution.

Source: pandasthumb.org

spaceplasma:

Exploding star remnants found in fossilized bacteria

Thousands of metres below the sea, trapped in the fossilized remains of ancient bacteria, exists the iron remnants of a supernova explosion that happened millions of years ago. An imprint, here on Earth, of a dying star.

Iron-60, an isotope of iron created only in supernovae, has been found in fossilised seabed bacteria. The preliminary findings, announced by Shawn Bishop of the Technical University of Munich at a 14 April meeting of the American Physical Society in Colorado, may be the first time that a specific star’s debris has been found in our fossil record. 

Iron-60’s half-life is relatively short when compared to the age of our solar system, so traces of the isotope on Earth suggests a direct interaction with a supernova in the planet’s history. The researchers searched for the isotope in fossils from seabed samples between 1.7 million to 3.3 million years old. They likely found traces of the isotope in fossils around 2.2 million years old.

The bacteria containing the Iron-60 are magnetotactic; they are strange organisms live in the seabed and align themselves with the Earth’s magnetic field. They extract iron from the water and sediment around them and create iron oxide crystals that are then preserved in the fossil record.

“For me, philosophically, the charm is that this is sitting in the fossil record of our planet,” said Bishop in a  Nature.com report. The isotope had previously been discovered in seabed samples, but not in the fossil record.

“We are all, as Carl Sagan put it, stardust,” Bishop told Wired.co.uk. “[We have now] likely discovered, within crystal nano-fossils left behind by primitive bacteria, […] still-live radioactive atoms that can only have been synthesized within the same kind of nuclear furnace — an exploding star — that forged the elements from which all live on Earth is made. The cycle comes full-circle.”

It has been estimated that the supernova happened around 2.2 million years ago, and that the stream of cosmic rays would have had an effect on the Earth’s atmosphere by increasing cloud cover. The supernova responsible for depositing the iron-60 has not yet been found, but possible suspects have been identified in the nearby Scorpius-Centarus association.

This isn’t the first time that distant astronomical events have made an impact on Earth. In 2012, researchers found a surplus of radioactive atoms in Japanese trees, hinting at a violent cosmic event around 1,200 years ago.

deconversionmovement:

He Helped Discover Evolution, And Then Became Extinct

Ask most folks who came up with the theory of evolution, and they’ll tell you it was Charles Darwin.

In fact, Alfred Russel Wallace, another British naturalist, was a co-discoverer of the theory — though Darwin has gotten most of the credit. Wallace died 100 years ago this day.

Continue Reading

molecularlifesciences:

5 Reasons Why CLARITY Will Change the Life Sciences

We’ve all seen the gorgeous 3D constructions of the brain created by Karl Deisseroth’s group using a technique called CLARITY. This technique is more than just the eye candy we love so much on Tumblr. I recently attended a lecture by Deisseroth, and his work is nothing short of Nobel prize worthy. 

Here are 5 reasons why CLARITY will change the molecular life sciences.

1. CLARITY clears fatty molecules.  Fats and other hydrophilic molecules absorb and diffract light, and by washing away the molecular structures that screen light, micrographs can be clear and crisp.  These images show a visible difference. 
2. CLARITY links proteins in a mesh-like gel.  Most of us know about formaldehyde and its ability to preserve biological matter.  Using a similar chemical reaction, proteins are kept in tact in their relative position by being linked to each other.  This means that even with the fatty parts washed away, the proteins will maintain their spatial organization. 
3. CLARITY holds on to proteins.  As a consequence of the chemical linking, the proteins of interest stay in place even when the sample is washed.  The amount lost is incredibly low compared to other methods of clearing, which means that the researcher will have a more realistic amount of protein in the sample.  More proteins means more gorgeous micrographs.
4. CLARITY means no more sectioning.  One of the greatest challenges for neuroscientists has been capturing whole neurons in vivo.  A single neuron can run the length of your leg.  CLARITY creates “never-sectioned” samples, removing the guess work of reconstructing slices. Personally, sectioning is my least favorite activity.
5. CLARITY allows for multiple labels. Drumroll please.  Finally, Deisseroth’s group has shown that samples can be labeled multiple times with high reliability.  The meshwork is tight enough that immuno-staining (i.e. labeling with antibodies) can be done multiple times with washing.  Most techniques are limited to 2-3 molecular probes at a time.  This provides an opportunity to visualize many protein targets. By stacking 3D images of each protein marker, the researchers create the colorful visuals seen above.

As you can guess, CLARITY resolves many of the largest challenges of molecular biology and related sciences, but there is one more bit of great news. The Stanford-based group released their protocol for everyone to use!

Viva la scientific revolution!

Read the original paper here, watch the video here, or view the Nature News article here. 

More like this at molecularlifesciences.tumblr.com

References:
Chung, K., Wallace, J., Kim, S. Y., Kalyanasundaram, S., Andalman, A. S., Davidson, T. J., … & Deisseroth, K. (2013). Structural and molecular interrogation of intact biological systems. Nature 496.151

Note:
CLARITY is the method used to prepare samples, it makes tissue see-through.  It is the confocal microscopy that focuses a laser on the sample an excites the fluorescent tags added by the researcher. 

10 insects that look like they belong in an alien world. [Click images to enlarge & for descriptions.]

10. Puss Moth Caterpillar

With their soft bodies and high protein content, caterpillars are usually incredibly vulnerable. To fend off predators, they often resort to scare tactics. Sometimes it’s in the form of bright, flashy colors; sometimes it’s in the form of mimicry—looking or acting like another, more dangerous insect. The Puss Moth caterpillar opts for mimicry, forming a bizarre looking “face” that resembles a vertebrate face scary enough to send most curious predators the other way.

The caterpillars are bright green and will often have a row of white spots on either side of their body. On the head is a pair of black “eye spots”—directly above a gaping “mouth” through which the true head of the caterpillar protrudes. The effect is startling, but it’s even creepier in action: if the caterpillar is touched anywhere on its body, it will instantly turn its “face” directly towards the attacker. Touch it somewhere else, and the head follows you, like a Mona Lisa from hell.

And if that doesn’t work, it can always spray out a mist of formic acid from the two horns on its back.

9. Devil’s Flower Mantis Idolomantis Diabolica

One of the largest types of praying mantis, the Devil’s Flower Mantis is also one of the strangest. And that’s saying a lot when you’re talking about praying mantids. Females of the species can measure up to 5 inches (13 cm) long, and have developed a range of natural coloring that allows them to mimic the Devil’s Flower, a type of orchid.

Mantids are predators, and their hunting style usually involves sitting motionless until their prey comes within reach, and then whipping their forearms out at lightning speed to snag flies, beetles, even, in some cases, birds. The Devil’s Flower Mantis uses color patterns that mimic a flower to actually lure its prey within reach.

8. Brazilian Treehopper

The image shown here is a model created by Alfred Keller, a German sculptor, in the 1950′s. But don’t let the fact that it’s a model fool you—the Brazilian Treehopper is definitely a real insect, and it’s barely even the strangest looking member of the treehopper family.

Similar to cicadas, treehopper insects are sort of like the Addams family of the insect world. Many of them sport some sort of odd structure on their backs, and we’re still not sure what the point of most of them are. In the case of the Brazilian Treehopper, the ball-like appendages are hollow chitin, and may be for the sole purpose of making it harder to eat.

7. Extatosoma Tiaratum

Anybody who’s ever seen Indiana Jones and the Temple of Doom should instantly recognize this monstrosity, commonly referred to as the Giant Prickly Stick Insect. As the largest known stick insect, the extatosoma tiaratum can reach lengths of 8 inches (20 cm) and is usually covered with large thorny spikes, which double as both camouflage and defensive armor.

Most of the time this insect attempts to blend in with its surroundings, but if it feels threatened it will rear up on its hind legs and spread out its front legs, like a scorpion. Interestingly enough, it also releases a chemical that is meant to scare away predators. To humans, it smells like peanut butter.

6. Pipevine Swallowtail Caterpillar

The Pipevine Swallowtail is a beautiful fluorescent blue butterfly that’s commonly found in North and Central America. Its larvae, on the other hand, is an armored congealed-blood-red caterpillar with tinted visor shades for eyes and a quadruple row of blunt horns running across its body.

The caterpillars live in groups while they are young, but over time they will wander off on their own before entering the chrysalis stage. They also change color as they grow, shifting from red to black, while their horns take on a bright orange hue. The bright colors are a warning—Pipevine Swallowtail caterpillars feed primarily on the Pipevine, a poisonous plant, and retain the toxins from the leaves in their own bodies.

5. Atlas Moth

Most of the time, it’s the caterpillar of a moth species that looks the strangest, while the moth itself is drab and uninteresting. Apparently, the Atlas moth didn’t get the memo. With a 10 inch (25 cm) wingspan, Atlas moths are believed to be the largest moth species on the planet. They also have a very unique trait—the front tips of their wings almost perfectly resemble a snake head poised to strike.

Nicknamed the Cobra moth for obvious reasons, Atlas moths are found in Southeast Asia, where they’re farmed for their silk.

4. Tailed Emperor Butterfly Caterpillar

Take a trip to the east coast of Australia around March or April and you might run into one of these strange creatures. The caterpillar of the Tailed Emperor butterfly looks pretty normal—from the neck down. Its head, though, definitely secures it a spot on this list.

From a broad, armor-plated forehead extend four bizarre horns that would be more at home on a dinosaur than anything from this millenium. The butterflies lay their eggs in groups, usually on Illawarra Flame trees, and the alien caterpillars emerge sometime around late March.

3. Spiny Flower Mantis - Pseudocreobotra wahlbergi

Another incredible looking mantis, the Spiny Flower Mantis (Pseudocreobotra wahlbergi) is, again, a flower mantis, pulling its bizarre ornamentation from the appearance of a flower. This mantis is very small, measuring only 1.5 inches (38 mm) and is found in select locations in Southern Africa.

And like most mantids, the Spiny Flower Mantis is a voracious cannibal, and the older they get the more likely they will be to eat other mantids that come across their path. Another interesting fact is that the female’s egg sac can be nearly three time larger than its own body.

2. Scorpionfly

While this insect looks like the result of some bizarre genetic experiment that spliced a scorprion stinger onto a wasp, that “stinger” is actually something much more innocuous: the fly’s genitals.

Nevertheless, it makes for a bizarre looking creature. Scorpionflies, or mecoptera, can be found all over the world, and have been around since the Mesozoic age. In fact, they’re believed to have been the forerunners of most of our modern moths and butterflies, collectively grouped in the Lepidoptera order.

1. Calleta Silkmoth Caterpillar

If Jackson Pollock and God had a design meeting, they would probably come up with something similar to the Eupackardia calleta larva, also known as the Calleta silkmoth caterpillar. With a massive color range and dangerous looking barbs, the Calleta silkmoth caterpillar is something most predators stay away from.

The moth is found in the Southern US, and the color pattern of the caterpillar changes based on age and environmental factors. It feeds mostly on the Mexican jumping bean, a plant found throughout Mexico, Texas, and Arizona.

post-mitotic:

mitotic spindles in a sand dollar (Dendraster excentricus) blastocyst

history lesson time:

Even with extremely crude microscopes…Flemming and the early cell biologists deduced the correct structure of the mitotic spindle by the end of the 19th century. They even provided evidence for its filamentous properties and a force acting to parallel to the spindle axis.

In 1952, Daniel Mazia and Katsuma Dan isolated entire mitotic apparatuses, showing that the mitotic spindle, chromosomes, centrosomes, and asters constitute an integrated complex separable from the rest of the cell.

confocal with fluorescent antibody against tubulin

credit: George von Dassow (Cell Picture Show)

The Secret Life of a Domestic Feline.  [Click images to enlarge.]

Ever wonder what your kitty is up to when roaming the neighbourhood outside? Now you can get a good idea thanks to a team from BBC Two’s Horizon program that collaborated with the Royal Veterinary College and armed dozens of feline-friends with GPS tracking devices and micro-cameras to dually record their daily activities. 

“Meet Ginger, Chip, Sooty, Orlando, Hermie, Phoebe, Deebee, Kato, Coco and Rosie. They are 10 of the 50 cats studied in the village of Shamley Green, Surrey, for Horizon’s programme The Secret Life of the Cat.

As part of one of the largest ever research projects into domestic cat behaviour, the Horizon team - aided by the Royal Veterinary College and Lincoln and Bristol Universities - tracked dozens of cats over several 24-hour periods using specially-designed collar GPS devices and tiny “cat cams”.

The result? Scientists discovered the cats appeared to timeshare territory to avoid confrontation with neighbouring felines and visit each others houses. However, the cat cam footage also revealed squabbles over territory remained. There was also an incident with a fox and with a nest of fledglings.” [x]

1. Ginger

Name: Ginger
Age: Five to 10 years     Sex: Male
Breed/colour: Ginger tomcat
Character: Intolerant and aloof, but also active and trainable. A good hunter. Known to fight with the neighbour’s cat and visits the neighbouring property
Roaming: Roams almost 200m (more than 600ft) from home and covers an area of about 0.3 hectares (0.7 acres)
Prey: Brings frogs, toads, birds or small mammals home most days

Expert view: “Ginger’s roaming is pretty average in terms of range or distance from home. However, on one of the days he was tracked he was more active than any of the other cats,” say researchers.

2. Chip

Name: Chip
Age: One to four years      Sex: Male
Breed/colour: Short-haired black and white moggie
Character: Active and stubborn, but also friendly, tolerant and trainable
Roaming: Visits other houses. Roams about 160m (530ft) from home, but covers 1.2 hectares (three acres)
Prey: Brings birds or small mammals home once or twice a week

Expert view: “Chip lives on the edge of the village and has the third largest roaming range of our 10 cats. He stuck to travelling through back gardens and by the side of a row of houses,” say researchers.

3. Sooty

Name: Sooty
Age: Five to 10 years      Sex: Male
Breed/colour: Short-haired black moggie/farm cat
Character: Friendly, tolerant and active, but somewhat aloof and calm. Doesn’t fight. Lives with sibling Socks
Roaming: Roams 186m (600ft) from home and covers nearly three hectares (seven acres)
Prey: Brings home small mammals a couple of times a week

Expert view: “Sooty has the largest roaming range of our 10 cats and liked to visit some trees on farmland next to some water. His house is on the edge of the village and so he has easy access to the countryside,” say researchers.

4. Orlando

Name: Orlando
Age: More than 10 years      Sex: Male
Breed/colour: Ginger moggie
Character: Used to be feral in Hong Kong. In good weather he refuses cat food and survives by hunting wildlife. He hates the cold and sleeps on the family’s range. Fights with Clawdius, another of the household’s cats.
Roaming: Roams 150m (500ft) from home but covers an area of more than two hectares (5.5 acres)
Prey: Brings home small mammals once or twice a week

Expert view: “Orlando appears to be a ‘regular’ hunter and travels into an area of open grassland and woods behind his house. He lives outside the village giving him easy access to the countryside,” say researchers.

5. Hermie

Name: Hermie
Age: One to four years      Sex: Male
Breed/colour: Black domestic shorthair
Character: Active and stubborn, but also friendly, tolerant and trainable. A hermaphrodite which is quite rare
Roaming: Roams about 170m (560ft) from home, but covers a larger area than any other cat - up to 3.3 hectares (eight acres)
Prey: Brings birds or small mammals home once or twice a week

Expert view: “Hermie is a hermaphrodite cat. He was regularly on the move within this area and was generally a very active cat when compared to others,” say researchers.

6. Kato

Name: Kato
Age: Five to 10 years      Sex: Male
Breed/colour: Long-haired, fluffy black and white moggie
Character: Tolerant, calm, friendly and trainable, but also bold and stubborn. Regularly fights with Phoebe, a tortoiseshell female
Roaming: Roams up to 93m from home and covers about a hectare (2.7 acres)
Prey: Brings birds or small mammals home a couple of times a week.

Expert view: “Kato appears to timeshare territory with Phoebe, a cat who lives on the opposite side of the road. They appear to avoid being out at the same time as one another,” say researchers.

7. Phoebe

Name: Phoebe
Age: Five to 10 years      Sex: Female
Breed/colour: Tortoiseshell moggie
Character: Active and friendly. A great hunter, especially in summer. Strays from home for days at a time. Regularly fights with neighbours’ cat, KatoRoaming: Roams about 140m from home and covers more than a hectare (more than three acres)
Prey: Brings birds or small mammals home a couple of times a week - more in summer

Expert view: “Phoebe appears to timeshare the road between her house with neighbouring cat Kato. The owners know the two sometimes fight. When one is active and outside, the other tends to be inside,” say researchers.

8. Deebee

Name: Deebee
Age: More than 10 years      Sex: Male
Breed/colour: Short-haired black tabby
Character: Sometimes friendly, but also aloof and intolerant. Hand-reared from three days old due to his mother’s death. Known to fight with other cats, including those he lives with
Roaming:Roams 150m (500ft) from home, but covers an area of more than two hectares (5.4 acres)
Prey: Never brings prey home

Expert view: “Deebee is a relatively new cat to the village and appears to be scoping out where to establish a territory. He lives in a house in the centre of the village surrounded by other pet cats,” say researchers.

9. Coco

Name: Coco
Age: One to four years      Sex: Female
Breed/colour: Black domestic shorthair
Character: Tolerant and calm as well as active and friendly. She loves cuddles and cosy spots. Hard to house train and fights with other cats
Roaming: Visits other houses. Roams up to 80m (260ft) from home and covers half a hectare (1.2 acres)
Prey: Brings birds or small mammals home a couple of times a week

Expert view: “Coco lives with another two cats - Bramble and Phoebus - but has a fairly average roaming range. However, she was one of the more active cats studied,” say researchers.

10. Rosie

Name: Rosie
Age: Five to 10 years     Sex: Female
Neutered: Yes
Breed/colour: British shorthair
Character: Friendly cat. Known to visit other houses and likes to hunt shrews. She fights with the cat next door
Roaming: Doesn’t roam far - just 40m (130ft) from home. She covers just 0.2 hectares (half an acre)
Prey: Although she likes to hunt shrews, she never brings prey home

Expert view: “Rosie spends a lot of time outside, but appears to have a quite a small territory. She spends nearly all of her time in her own garden, and does not venture much further,” say researchers.

“BBC Two is airing a documentary on June 13, 2013 about the project. The scientists involved plan to publish a formal paper about their work in the future, Wilson wrote.” [x] If you missed the air-date you can watch here on the BBC iPlayer. Be forewarned that those living outside of the UK aren’t able to view the videos as of yet.

Read more here, & here. Read more about the science and technology behind the study from Alan Wilson of the Royal Veterinary College.

knowledgethroughscience:

Scientists at Princeton University used 3-D printing to create a functional ear that can “hear” radio frequencies far beyond the range of normal human capability.

“The design and implementation of bionic organs and devices that enhance human capabilities, known as cybernetics, has been an area of increasing scientific interest,” the researchers wrote in the article which appears in the scholarly journal Nano Letters. “This field has the potential to generate customized replacement parts for the human body, or even create organs containing capabilities beyond what human biology ordinarily provides.”

The finished ear consists of a coiled antenna inside a cartilage structure. Two wires lead from the base of the ear and wind around a helical “cochlea” — the part of the ear that senses sound — which can connect to electrodes. The ear in principle could be used to restore or enhance human hearing. Electrical signals produced by the ear could be connected to a patient’s nerve endings, similar to a hearing aid.

jtotheizzoe:

How did feathers evolve?

Carl Zimmer, an elegant peacock among science writers, delivers this lesson on where bird feathers came from. The shared anatomy between dinosaurs and birds extends beyond the wishbone to their equally functional and extravagant plumage. Recent fossil finds give us hints about the colors and forms that adorned some prehistoric reptiles, from frilly crests to fuzzy proto-wings.

Dinosaurs didn’t take to the air for tens of millions of years after the first feathers showed up, and we don’t yet know exactly how that happened. But we know that the evolution of these delicate, beautiful and functional forms carried some dinosaurs aloft to a higher branch on the tree of life, and from that branch lept the first bird.

(view the full lesson at TED-Ed)

sciencenote:

28 April 2013

Recoating Damaged Nerves

Nerve cells in our brains and bodies have long thin protrusions called axons, which transmit electrical signals both to other nerve cells and to body tissues. Wrapped around these axons are multiple thin layers of a substance called myelin, which not only protects the axons but also speeds up their signal transmission. Myelin is itself a type of cell called a Schwann cell and, if myelin becomes damaged by physical injury or disease – such as multiple sclerosis – the Schwann cells attempt to re-myelinate the axons. But the process is often insufficient and the damaged nerves might never fully regain their function. Researchers would thus like to enhance the natural re-myelination process to help damaged cells recapture their lost potential. A new technique that allows re-myelinating Schwann cells (stained green) to be distinguished from undamaged myelin (stained red) should help researchers understand the process and ultimately design treatments to improve it.

Written by Ruth Williams

• Philip Horner
• University of Washington, USA
• Published in PNAS 110(10): 4075-4080 

(via thesciencenotebooks)

rhamphotheca:

The Deepwater Canyons 2013: Pathways to the Abyss expedition is underway!

We’ll be posting logs from the field soon, but in the interim, do you have a question you’d like to ask one of the explorers? If so, check out our “Ask an Explorer” page and then fire away:

http://oceanexplorer.noaa.gov/explorations/13midatlantic/logs/ask/ask.html.

About the image: Closeup view of Paragorgia arborea (bubblegum coral) encountered during last year’s expedition.

Source: http://oceanexplorer.noaa.gov/explorations/12midatlantic/logs/sep7/media/coralcloseup.html.

(via: NOAA)

beautymagnified:

A truly weird animal by Arthur Anker on Flickr.

Via Flickr:
A thalassematid echiuran from Madang, Papua New Guinea, an odd animal that constantly changes its shape, is “never the same” … these 6 photos show the same individual, I also made nice videos of the remarkable peristaltic movements

thebrainscoop:

The Brain Scoop - Episode 22
Kids’ Q&A

Considering how many tours we give to elementary school-aged children, I thought it would be a fun episode to answer some of their questions for a video.  My sister is a 4th grade teacher and was more than willing to help out with this episode! 

We uploaded this episode last night and I’m pleasantly surprised by the number of comments that are something like, This episode was made for kids but I still learned something. Awesome.  Children have a wonderful way of asking questions without feeling embarrassed or with the prerequisite This might be a stupid question….  Fostering that imagination and curiosity is essential to inspiring new generations of scientists! 

rhamphotheca:

Zombie Worms Drill Whale Bones With Acid

by Douglas Main

So-called zombie worms — and yes, they actually exist — like to munch on whale bones for dinner. The creatures also use the bones for shelter. Spread throughout the world’s oceans, zombie worms are quite adept at making the bones of whales and other large marine animals look like Swiss cheese.    

But these worms don’t have any mouthparts with which to gnaw the holes. So how do they do it? A study published in the May 1 online edition of the journal Proceedings of the Royal Society B found that rather than being “bone-drilling” worms, they’re actually “bone-dissolving” worms: The worms’ skin produces acid in large quantities to break down bones…

(read more: Live Science)             

(photo: Martin Tresguerres et al / Proceedings of the Royal Society B)

Enjoy some nature gifs in HD. [Click images to enlarge.] 

“We’ve picked out a few favorites from Head Like An Orange, home of hundreds of amazing nature GIFs.

Marinus is a 28-year-old from the Netherlands, and he makes GIFs. But not just any GIFs: his Tumblr, Head Like An Orange, is a collection of some of nature’s most stunning, weirdest, sweetest, and funniest moments. At least, they are the best moments captured on film, put into TV shows, and edited down into short, spellbinding loops.

Are the ones we’ve picked out here the best GIFs on Marinus’s blog? We don’t know—there are hundreds to choose from, and they are all wonderful. But here are a few of the highlights.”