Stories tagged biology

When it rains....

by mdr on Jul. 25th, 2013

...frogs use leaves as umbrellas! Very cool photo. The little critter is about 2 inches tall.

The gene sequences of some 3500 life forms discovered in ice cores from a deep lake buried a couple miles (3700 meters) beneath glaciers in Antarctica have been sorted out and found to be about 94 percent bacteria and 6 percent Eukarya. More than half of the life is made up of new genera and species previously unknown to science. That's kind of amazing. A while back, as the Russian-led team of scientists was just breaking through to the lake's surface, I put up what I thought was a short, satirical post about Lake Vostok, and what the researchers might encounter. Maybe it's not so satirical. These are life-forms that haven't seen the light of day (or the surface of the Earth) for more than 15 million years! Although none of them appear to be giant, carnivorous carrots revived from their cryogenic tombs, is it a good idea to bring these unknown microbes back up from their icy isolation? Are we just asking for trouble? What do readers think?

Open study at PloS

NOTE: The video embedded above is only the first of 4 parts of the 49 minute BBC documentary, The Lost World of Lake Vostok. The remaining parts can be viewed in the clips below. It's worth watching.

Lake Vostok, part 2 of 4
Lake Vostok, part 3 of 4
Lake Vostok, part 4 of 4

The US Supreme Court ruled unanimously that individual human genes can not be patented because they occur naturally and aren't patent eligible. Gene sequences, however, according to the court ruling, could be patented. Read more at The Scientist magazine website.

Ho hum, another battle for supremacy
Ho hum, another battle for supremacyCourtesy wynner3
Bring it!
Bring it!Courtesy ltshears
They seem fairly evenly matched. I don't know why, but my money would be on the tiger. Who do you think would win? news


Coelacanth: model in the SMM paleo lab. Photo by Mark Ryan.
Coelacanth: model in the SMM paleo lab. Photo by Mark Ryan.Courtesy Fancy Horse (underwater background)
The genome of the coelacanth, the world's best known living fossil, has been sequenced by an international team of researchers and is revealing something scientists already suspected: that the primitive-looking fish has evolved more slowly than most other organisms. The coelacanth is related to the lungfish and several extinct Devonian fish species that are considered precursors to land dwelling tetrapods. Kerstin Lindblad-Toh is senior author of the study which appeared recently in the science journal Nature.

"We often talk about how species have changed over time, but there are still a few places on Earth where organisms don't have to change, and this is one of them," Lindblad-Toh said. "Coelacanths are likely very specialized to such a specific, non-changing, extreme environment -- it is ideally suited to the deep sea just the way it is."

Lindblad-Toh is scientific director of the Broad Institute's vertebrate genome biology group in Cambridge, Massachusetts, which did the genome research. The institute is linked to both MIT and Harvard.

The genetic map, which involved sequencing some 3 billion letters of DNA, also showed (via RNA content) that tetrapods - four-legged land dwelling animals - though related to both coelacanths and lungfish, are more closely related to lungfish and followed that line rather than that of the coelacanth. We humans also branched off that same line. The genome of a lungfish is composed of over 100 billion DNA letters, making it a much more difficult task to sequence, so for the time being, the coelacanth's DNA makes for a reasonable alternative for study.

"This is just the beginning of many analyses on what the coelacanth can teach us about the emergence of land vertebrates, including humans, and, combined with modern empirical approaches, can lend insights into the mechanisms that have contributed to major evolutionary innovations," said professor Chris Amemiya at the University of Washington, and the paper's co-author.

Fossil coelacanth: not much has changed in 350 million years.
Fossil coelacanth: not much has changed in 350 million years.Courtesy photo by Haplochromis via Wikipedia Creative Commons
When Louis Agassiz named the first fossil coelacanth back in 1836, the Swiss paleontologist probably never imagined that a nearly identical descendent of the primitively constructed Devonian-aged fish would one day be found still inhabiting the world's oceans. The coelacanth was thought to have gone extinct along with the non-avian dinosaurs at the end of the Cretaceous period. None have been found in the fossil record after that time, but two extant species are known today. The first specimen Latimeria chalumnae was netted off the coast of South Africa in 1938, near the Chalumnae river and retrieved by East London Museum curator Marjorie Courtenay-Latimer who discovered what she called "the most beautiful fish I'd ever seen" in the catch of local fisherman, Henrik Goosen. Since then several more coelacanths have been caught, including the Indonesian species, Latimeria menadoensis, from the Indian Ocean.

The remarkable prehistoric throw-back, sometimes referred to as "old four legs" because of its leg-like fins, hasn't changed much in its 350 million year history. A member of the clade of lobe-finned fishes called Sarcopterygii, coelacanths retain primitive characteristics such a notochord, a hollow fluid-filled tube made of cartilage that underlies the spine over the length of its body. In all other vertebrates, the notochord is an anatomical structure that appears briefly only during the embryonic stage but not in adults. Not so with the coelacanth. It also possesses, primitive shark-like intestines, a linear heart, and tightly-woven armor-like scales (known as cosmoid) that are only found on extinct species of fish. The coelacanth's brain case contains only 1.5 percent gray matter - the other 98.5 percent of space is filled with fat. The other end of the coelacanth body begins to taper before expanding into a strange, three-lobed tail. Its most notable features are its lobed pectoral and pelvic fins that are structured with bones that look like toes, and move in an alternating tetrapod manner. An electroreceptive rostal organ located in its snout is used to detect prey, and the coelacanth is the only living animal that can unhinge a section of the its cranium to increase the gape of its mouth, enabling it to consume larger prey.

The blue or brown, white-speckled coelacanths prefer deep-water environments, and can reach six and a half feet in length and weigh upwards to 175 pounds. For some reason no living coelacanth has managed to survive more than a single day in captivity. With a dwindling population estimated at only 500-1000 individuals, the coelacanth was declared an endangered species in 1989.


Broad Institute news
Coelacanth info at
More coelacanth info
NatGeo article
Take Nova's Coelacanth Quiz


OMG! Can nothing stop them?: According to a new study, mosquitoes, those buzzing, biting, itch-producing flying pests that make life miserable for many of Earth's inhabitants (mainly we humans), can easily adapt to Deet, one of the commonly used ingredients in insect repellents.
OMG! Can nothing stop them?: According to a new study, mosquitoes, those buzzing, biting, itch-producing flying pests that make life miserable for many of Earth's inhabitants (mainly we humans), can easily adapt to Deet, one of the commonly used ingredients in insect repellents.Courtesy Mark Ryan (with photo help from NASA)

We've all seen them, those great B-films where a giant, vicious monster from under the sea, or invaders from outer space arrive to cause mayhem across our cities and generally mess up our way of life. In the end, it seems no matter who or what it was that was attacking us, be it Mothra, Godzilla, or some race of belligerent extra-terrestrials, we could always count on the military to save our collective behind.

Unfortunately, with mosquitoes, that might now be the case anymore.

Scientists are reporting that Deet, one of the most widely used active ingredients in insect repellents, loses its effectiveness against mosquitoes shortly after those ubiquitous, blood-seeking winged vermin are first exposed to it.

Deet - the common name for N,N-diethyl-meta-toluamide - was developed by the US Army after the Second World War to help combat insects during jungle warfare. It was used extensively in the Korean and Vietnam wars, but mosquitoes seem to be able to adapt quickly to it.

"Mosquitoes are very good at evolving very very quickly", said Dr. James Logan of the London School of Hygiene and Tropical Medicine and co-author of the study. "There is something about being exposed to the chemical that first time that changes their olfactory system - changes their sense of smell - and their ability to smell Deet, which makes it less effective."

So what I want to know is where does that leave us here in Minnesota where the mosquito constantly competes with the Common Loon for the title of State Bird? Maybe it's time to start digging the bunker in the backyard.

BBC Science news
Original study at Plos One
The Life Cycle of the Mosquito
All about mosquitoes on NatGeo

Turkey censors Darwin and evolution
Turkey censors Darwin and evolutionCourtesy Public domain via Wikipedia
There’s concern in the scientific community as the Republic of Turkey seemingly expands its censorship of evolution. Turkey is one of the more secular Islamic countries, but recent events seem to show a growing trend in the Turkish government's crumbling stance on evolution. In 2008, the country’s Council of Information Technology and Communications (BTK) banned access to evolution websites including, and (Access to some other previously banned evolution sites was later allowed). The next year, the cover story of a science magazine celebrating the 200th anniversary of Darwin’s birth was removed just before publication but later reinstated after public outcry. In 2011, Turkey’s Council of Information Technology and Communications (BTK) released secure “Child Profile” Internet filters that, along with guarding against access to pornography, blocked sites containing words such as “Darwin” and “evolution”.

Now the Scientific and Technical Research Council of Turkey (TÜBITAK) has stopped publication and sale of all evolution books its archives. The TÜBITAK website has long listed books by such evolution writers as Richard Dawkins, Stephen Jay Gould, and J a m e s W a t son as “out of stock”, but now titles by these and other writers like will no longer be available.

Turkey's Hurryiyet Daily News
Telegraph story
Nature editorial

Fewer moose on the loose: Climate change is taking a toll on Minnesota's moose population, putting them in line to be added to the state's species with special concerns list.
Fewer moose on the loose: Climate change is taking a toll on Minnesota's moose population, putting them in line to be added to the state's species with special concerns list.Courtesy USDA Forest Service
While it's been a pretty good 16 years for Minnesota wolves and bald eagles, that's not been the case for moose. The behemoths will likely be moving on to the state's list of species with special concerns, according to the Minnesota Department of Natural Resources. In total, 67 animals and 114 plants are being proposed to be added to the lists while 15 plants and 14 animals – including wolves and bald eagles – have rebounded in numbers to be removed from the designations. Climate change is being credited as the big threat to Minnesota's moose population.

...And these beautiful close-up photos of human eyes by photographer Suren Manvelyan show it. The post also includes some of the science behind the human eye.

More of these remarkable photos can be found at Manvelyan's website.

Claude the alligator
Claude the alligatorCourtesy Chris Pederick
Sensory organs dotting the heads of members of the crocodilian family show evidence of being more sensitive to touch than even human finger tips. Some of the literally thousands of minute pigmented bumps, called Integumentary sensory organs ( ISOs) covering the reptiles' tough, armored skin are used to detect surface ripples or water movement for determining prey location. But many of the remaining receptors can detect the slightest touch from potential prey, and cause a croc's or gator's jaws to snap shut with lightning speed. The study was done by researcher Duncan Leitch and biologist Kenneth Catania, and appears in the Journal of Experimental Biology.

Story at