Rewriting the Bird Family Geneology
Jun 30 at 8:08pm by Aileen
Bird-watching is one of the most popular pastimes in the world, for people from all walks of life. Our fascination with birds in all their sizes, colors and habitats thus makes for a ready field of study in biology, where bird evolution used to maintain a fairly rigorous tree-of-life.
Not so much any longer, since researchers with the Early Bird Assembling the Tree-of-Life Project centered on the Field Museum examined DNA from all major living groups of birds and discovered that phylogenics had it all wrong!
Huge Genome Phylogenic Study of Birds Re-Writes Bird Evolution
As an indicator of just how wrong it was, DNA analysis has determined that falcons - those swift and trainable birds of prey - are NOT closely related to hawks and eagles. Whoa. Spokespersons for the project say the entire understanding of bird evolution will need to be re-written with this new information, and that information itself raises some further questions about concurrent and repeated evolution of certain traits at different times in different families.
“We now have a robust evolutionary tree from which to study the evolution of birds and all their interesting features that have fascinated so many scientists and amateurs for centuries,” Reddy said. “Birds exhibit substantial diversity (largest of the tetrapod groups), and using this ‘family tree’ wwe can begin to understand how this diversity originated as well as how different bird groups are interrelated.”
The Surprising Technology of the Bacterial Flagellum
Jun 24 at 2:02pm by Aileen
[Photo Credit: Zina Deretsky, NSF]
Scientists at Indiana University Bloomington and Harvard published a report in Science June 20 describing a protein “clutch” that disengages the bacterial tail from the “tiny but powerful engine” that powers its rotation. The flagellum is the means that many bacterial cells - including Bacillus subtilis used in this research - use to ’swim’ in liquid environments where they live.
Microscopic ‘Clutch’ Puts Flagellum in Neutral
The clutch mechanism was discovered by accident when the researchers were studying the formation of bacterial “biofilm,” where the cells accumulate and become stationary, biofilms are involved in bacterial infections. It is hoped that the discovery will give nanotechnologists some ideas about how to regulate tiny engines they create in the lab.
“We think it’s pretty cool that evolving bacteria and human engineers arrived at a similar solution to the same problem,” says IU biologist Daniel Kearns, leader of the project.
Pigeon Self-Recognition Better Than 3-Year Old Human’s
Jun 17 at 3:03pm by Aileen
Science Daily reported over the weekend that Keio University research has demonstrated that pigeons show superior self-recognition abilities to three year old humans.
Professor Shigeru Watanabe and graduate student Kohji Toda managed to train pigeons to recognize themselves in real-time using mirrors and videotape, then found that their pigeons can recognize themselves in video images with a 5 to 7 second delay. Human 3-year olds typically have trouble recognizing themselves with just a 2 second delay.
Thus pigeons now join chimpanzees, gorillas, dolphins and elephants in having the ability to recognize themselves, which means that particularly large brains aren’t necessary to the ability. It seems that we are learning that the other forms of life we share our planet with are quite a bit smarter than we’ve traditionally given them credit for!
More Cool, Mind-Blowing Facts!
Jun 6 at 3:03pm by Aileen
Here are some more strange (and very disturbing) facts about the human body, from Vicki over at the One Big Health Nut blog…
• Nearly 50% of the bacteria in your body (and humans harbor 3 times more bacterial cells than human cells) live on the surface of your tongue, which (by the way) is the strongest muscle in your body. Probably a good reason why Mommy-Kisses work better than Mommy-Licks on boo-boos.
• The incidence of immune system diseases has increased more than 200% in the last five years. Yikes! Is that environmental?
• By the time a person is 35 years old, s/he begins losing about 7,000 brain cells a day which are never replaced. Whoa. I’d say something profound about that, but I forgot what the subject was…
• A moderate sunburn damages blood vessels in the skin so seriously that it takes between four and fifteen months for them to heal. The reason I keep SPF 50 on hand all summer.
• Right-handed people live an average of nine years longer than left-handed people. Need I remind readers that correlation does NOT equal causation?
Go on over to One Big Health Nut and read the rest for yourself!
Evolution’s Practical Joke is Still Funny
May 12 at 6:06pm by Aileen
…after all these years
That great practical joke that life’s designer [be it blind nature or purposeful god] played is still with us to confound orderly notions of biological evolution. The genome of Australia’s duck-billed platypus has been sequenced by an international group of scientists led by researchers at Washington University School of Medicine in St. Louis.
The venomous, egg-laying, duck-billed, web-footed, beaver-tailed mammal is one of the earliest offshoots of the mammalian lineage from when it split off from primitive ancestors some 166 million years ago. The genome confirms the chimeric status of this odd animal which displays traits of reptiles, birds and mammals.
As part of their analysis, researchers compared the platypus genome with human, mouse, dog, opossum and chicken genomes. Chicken genome was chosen because it represents a group of egg-laying animals that includes extinct reptiles that passed on much of their DNA to mammals over the course of evolution. When analyzed, the genetic sequences for venom production in the male platypus was found to have arisen from duplications in a group of genes evolved from ancestral reptilian genomes. They hypothesize that duplications in those very same genes led to the evolution of venom independently in modern reptiles.
The project involved sequencing about 2.2 billion base pairs and 18,500 genes. The Platypus has 52 chromosomes and an unusual 10 sex chromosomes. The platypus X chromosome also bears a striking similarity to the sex chromosome of birds.
Final conclusion? The duck-billed platypus is just as bizarre a mix-and-match critter genetically as it appeared to be when the first specimens were shown to the scientific community some 200 years ago. Skeptics then believed the animal was someone’s idea of a practical joke hoax. Turns out it really is a genetic practical joke, but it comes as-is in nature.
Links:
Platypus Genome Explains Animal’s Peculiar Features
Daily Mail: It’s a bird, it’s a beaver…
Surprise! Human Babies Should Drink Human Milk
May 7 at 6:06pm by Aileen
Michael Kramer, a professor of pediatrics at McGill University reported this week that breastfeeding raises children’s IQ and improves their academic performance later in childhood.
Their study evaluated children in 31 Belarusian hospitals and clinics. Half of the women were directly encouraged to breastfeed exclusively, the other half did things the ‘normal’ way (for Belorussia). Six and a half years later the children’s IQs were tested and their teachers submitted academic performance ratings. Scores on both were significantly higher for the children of women encouraged to breastfeed, though there is no indication that the researchers confirmed how many of those mothers actually did breastfeed or for how long.
“Our study provides the strongest evidence to date that prolonged and exclusive breastfeeding makes kids smarter,” Kramer said.
Read the rest of this entry »
Where Have All the Salmon Gone?
May 5 at 4:04pm by Aileen
A declaration of commercial fishery failure by Commerce Secretary Carlos Gutierrez has paved the way for Congress to allot funds for alleviating financial hardship among the West Coast’s commercial Chinook salmon fishing industry off California and Oregon. The crisis has been building steadily every year since 2000, culminating in this latest action - the commercial salmon fishing industry has essentially been shut down.
National Oceanographic and Atmospheric Administration [NOAA] researchers suggest that changes in ocean conditions - possibly due to global warming - are to blame, along with loss of freshwater habitat for salmon spawning, a chronic problem.
There will be some coho salmon fishing allowed off the coast of Washington and northern Oregon, but there will be financial hardship in that industry as well due to strict limits. This crisis has been building for years, attempts along the way to mitigate it have proven to exacerbate the situation, such as the introduction of farmed salmon. Fish stock collapses in traditionally abundant fisheries off both coasts and elsewhere in the world bode ill for the seafood component of the human food supply, just as the worldwide food crisis heats up around the world for staple crops like corn and wheat and rice.
We could be beyond a tipping point right now, and things could get a bit more than just ‘interesting’ over the next months. Will science be able to come to the rescue, or will it remain helpless to mitigate the collapse of world food supplies? Stay tuned…
Links:
“Fishery Failure” Declared for West Coast Salmon Fishery
Hatchery Controversy Takes on New Significance as Wild Chinook Populations Crash
Escaped Farmed Salmon Infiltrate Fitter Wild Populations
Dramatic Declines in Wild Salmon Populations Linked to Farmed Salmon
World’s Oldest Tree is a Spruce in Sweden
Apr 21 at 9:09pm by Aileen
Most school children have at one time or another encountered a photo of a twisted bristlecone pine tree in California purporting to have begun its life before Abraham left Ur [the ‘Methuselah’ tree at ~4767 years old]. Science Daily reported last week that a spruce tree has been discovered in the Dalarna province of Sweden that is twice that age!
Yes, this not very old-looking little tree has been dated by researchers at Umeå University’s physical geography department at ~9550 years old. Just as interesting is that this ancient tree is a genetically identical clone of a previous tree - from whose roots it sprouted all those many years ago - and which left a few scraps of old wood in the area for researchers to analyze and a laboratory in Miami, Florida to date via C-14.
Researchers combing the Swedish mountains from Lapland to Dalarna have discovered a cluster of about 20 spruces that are all more than 8,000 years old. Which has to qualify the grove as the most ancient stand of virgin timber on the planet.
Nature’s Oldest Profession
Apr 16 at 4:04pm by Aileen
Just Like Penguins and Other Primates, People Trade Sex for Resources
A research scientist at UMich School of Public Health has established through interviews with 475 undergraduates that humans exchange resources (or merely clout) for sex, just like penguins, hummingbirds and other species of beings on this planet. His paper, “Young Adults Attempt Exchanges in Reproductively Relevant Currencies,” is published in this month’s Journal of Evolutionary Psychology.
Not that the idea of trading sex for resources is something unheard of in human society. Or even that in cultures where marriages are arranged among parents and grandparents before the young are old enough to walk, the arrangements are all about relative wealth and social standing - things considered valuable in the societies.
It is interesting that biologists (yes, the evo-psych folks too) have just recently figured out that their traditional reliance on exclusivity in sexual selection as a primary mechanism of directional evolution is not nearly as cut and dried as they long assumed it was. Given that cheating on spouses and general promiscuity have turned out to be fairly rampant in birds and beasts - the beauty of that peacock’s tail or the size of that ape’s manly parts doesn’t prevent lesser males from getting their genes into the pool after all…
There’s a reason we call it “The Oldest Profession.” Turns out, it’s even older than humans!
The Hindu Goddess Baby
Apr 9 at 11:11pm by Aileen
For something different and profound, consider the case of a baby girl named Lali born near New Delhi, India on March 11. She has a rare birth defect called diprosopus that gave her two faces on one head. ABC News reported that the resident medical officer of the Saifi Hospital where Lali was born has thus far been unsuccessful in his attempts to convince the parents to allow CT scans or MRI to determine whether there are duplicated internal organs or invisible, life threatening deformities that might be corrected by surgery.
Most babies with this condition are stillborn or die shortly after birth, but Lali so far has shown no breathing or digestion difficulties, both mouths are being fed. She was born normally and left the hospital with her mother 8 hours after birth.
This condition is not technically a case of cojoined twinning, where a single embryo duplicates and does not completely separate. Rather, it is due to malfunctioning in the developing embryo of a single protein called Sonic hedgehog homolog [SHH]. SHH protein governs the width of the face and features, and governs proper development of the brain and spinal cord via a signaling cascade.
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