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Posts Tagged ‘evolution

“Such is the essential mystery”*…

 

For about a billion years, life on earth was a relatively simple proposition: it was composed entirely of single-celled organisms (prokaryotes) in either the bacteria or archaea families.  Then, about 2.1 billion years ago, one of those single-celled critters crawled inside another; the two merged, and a new kind of life– multi-cellular (eukaryotic) life– was born…

This inner cell—a bacterium—abandoned its free-living existence and eventually transformed into mitochondria. These internal power plants provided the host cell with a bonanza of energy, allowing it to evolve in new directions that other prokaryotes could never reach.

If this story is true, and there are still those who doubt it, then all eukaryotes—every flower and fungus, spider and sparrow, man and woman—descended from a sudden and breathtakingly improbable merger between two microbes. They were our great-great-great-great-…-great-grandparents, and by becoming one, they laid the groundwork for the life forms that seem to make our planet so special. The world as we see it (and the fact that we see it at all; eyes are a eukaryotic invention) was irrevocably changed by that fateful union—a union so unlikely that it very well might not have happened at all, leaving our world forever dominated by microbes, never to welcome sophisticated and amazing life like trees, mushrooms, caterpillars, and us.

Read the extraordinary story of how one freakish event may well account for all sophisticated life on earth in “The unique merger that made You (and Ewe, and Yew).”

* Lao Tzu

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As we fill out our family trees, we might send microscopic birthday greetings to Carl Woese; he was born on this date in 1928.  A microbiologist, Woese recognized and defined (in 1977) the existence of archaea as a third domain of life, distinct from the two previously-recognized domains, bacteria and “life other than bacteria” (eukaryotes).  The discovery revolutionized the understanding of the “family tree” of life.  And the technique he used to make it– phylogenetic taxonomy of 16S ribosomal RNA– revolutionized the practice of microbiology.

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Written by LW

July 15, 2014 at 1:01 am

“Dinosaurs did not walk with humans. The evolutionary record says different. They gamboled”*…

 

Emily Graslie, host/writer of the educational YouTube series The Brain Scoop, has branched out to manage the wonderful Tumblr “…is not a dinosaur.”

This blog is a result of an erroneous mistake; one day I referred to Dimetrodon as a mammal-like reptile in front of a vertebrate paleomammalogist. These animals are not at all members of Reptilia; they are Synapsids – four-legged, back-boned animals that span back 315 million years on a completely different evolutionary branch on the tree of life.

Since then, I’ve found Dimetrodon partying with members of Dinosauria across the pages of coloring books and frolicking in the aisles of toy stores, surrounded by lifeforms which evolved some 66 million years after those ancient mammalian relatives…

And she’s shared; for example…

aurusallos:

isnotadinosaur:

This is one of my favorites – I’ll reblog whomever points out all of the discrepancies in this one image. You’ll also get a puppy*
*probably not

Upper-left feathered thing: probably an Archaeopteryx, but they have been proven to have black feathers. Although kudos to the authors/artists for allowing feathered dinosaurs to somewhat grace the cover! (Darn publishing logos)

Left green thing: an aetosaur, most likely. NOT DINOSAURS

Dimetrodon: PELYCOSAUR, NOT A DINOSAUR, SYNAPSID NOT A DIAPSID, UGHHHHHHHH. DIDN’T EVEN LIVE IN THE MESOZOIC.

Stegosaurus: head shape wrong, and dopey tail is not anatomically correct

Blue Ornithomimus thing: FOUR TOES ON THE GROUND? I don’t think so! And pronated wrists, not to mention the lack of feathers…

Protoceratops: legs sprawled out to the side instead of underneath, also missing the lower beak

Velociraptor pair: NO FEATHERS, TOO BIG, BROKEN HIPS (Sauruschian hips followed a 90 degree rule, meaning the femur does not bend back more than 90 degrees), more pronated wrists, wrong skull shape, and what are toe claws

Assumed Pteranodon: wimpy arm and shoulder musculature, missing pyncofibers, and wrong skull shape (although it might be viable, I’m scared to continue going through and trying to find pterosaur skeletals right now because of David Peters and his misleading work).

Also, many of these creatures are geographically misplaced, so even if they weren’t all from different time periods (Permian-Cretaceous), they probably wouldn’t have interacted much.

And, of course, the slightly off-center type of the title of the book is bugging me as a graphic design freak, but oh well.

ETA: More about the Dimetrodon: This illustration shows it with erect legs when it actually had sprawling legs, and the skull/mouth shape is not accurate either.

They just messed up bad with this one.

ETA2: While I do not know that much about paleobotany, I believe that most of the plants presented are fairly accurate.

I’m so proud I could cry.

 More disambiguation of the distant past at … is not a dinosaur.

* Steve Martin

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As we make Jurassic judgements, we might spare a thought for The Right Honorable John Lubbock, 1st Baron Avebury PC FRS DCL LLD; he died on this date in 1913.  A banker by trade (and family tradition), Lubbock was an avocational scientist who made significant contributions to ethnography, several branches of biology, and– as a friend and advocate of Darwin– the debate over evolution, and was a central force in establishing archaeology as a scientific discipline.

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Written by LW

May 28, 2014 at 1:01 am

Caveat Lector!…

 

 xkcd

E.g.,

A July 2011 hoax study correlated Intelligence Quotient (IQ) and Browser Usage, specifically asserting that Microsoft Internet Explorer users had a significantly lower I.Q. than other users. The study was reported by over 30 news outlets including NPR, Forbes, CBS News, San Francisco Chronicle, The Inquirer, and CNN. The perpetrator made little effort to conceal the deception by publishing it on a freshly created domain name with a parking lot as the corporate address, and was surprised that so many reputable outlets did no fact checking.  [source]

From Nature, help:  “Twenty Tips For Interpreting Scientific Claims.”

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As we marshall our grains of salt, we might spare a thought for Herbert Spencer; he died on this date in 1903. A prominent philosopher, biologist, anthropologist, sociologist, and prominent classical liberal political theorist of the Victorian era, Spencer was an early champion of evolutionary theory; it was he who coined the phrase “survival of the fittest” (some scholars suggest, before Darwin published).  Spencer’s enthusiasm for evolution spread to what has become known as Social Darwinism, the belief that society is governed by the same principles of natural selection as species (though Spencer also stirred in a measure of Lamarckism).

Spencer’s work was widely-known and discussed; he was probably the first, and possibly the only, philosopher in history to sell over a million copies of his works during his own lifetime.  Indeed authors ranging from Eliot and Hardy, through Tolstoy and Shaw, to Lawrence and Borges have cited his influence.

 

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Written by LW

December 8, 2013 at 1:01 am

Diversity…

Okay, what? Shut up, evolution, this cannot actually be a bird. Are you high?

WTF Evolution: “Honoring natural selection’s most awkward creations. Go home, evolution, you are drunk.”

The wolffish is actually modeled after evolution’s cousin Frank. Evolution has always secretly hated its cousin Frank.

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As we think over trial and error, we might recall that it was on this date in 1897 that the Indiana State House of Representatives passed Bill No.246 which gave pi the exact value of 3.2– a nice, round… and wrong number.

Hoosier Dr. Edwin J. Goodwin, M.D, a mathematics enthusiast, satisfied himself that he’d succeeded in “squaring the circle.”  Hoping to share with his home state the fame that would surely be forthcoming, Dr. Goodwin drafted legislation that would make Indiana the first to declare the value of pi as law, and convinced Representative Taylor I. Record, a farmer and lumber merchant, to introduce it.  As an incentive, Dr. Goodwin, who planned to copyright his “discovery,” offered in the bill to make it available to Indiana textbooks at no cost.

It seems likely that few members of the House understood the bill (many said so during the debate), crammed as it was with 19th century mathematical jargon.  Indeed, as Petr Beckmann wrote in his History of Pi, the bill contained “hair-raising statements which not only contradict elementary geometry, but also appear to contradict each other.”  (Full text of the bill here.)  Still, it sailed through the House.

As it happened, Professor Clarence Abiathar Waldo, the head of the Purdue University Mathematics Department and author of a book titled Manual of Descriptive Geometry, was in the Statehouse lobbying for the University’s budget appropriation as the final debate and vote were underway. He was astonished to find the General Assembly debating mathematical legislation.  Naturally, he listened in… and he was horrified.

On February 11 the legislation was introduced in the Senate and referred to the Committee on Temperance, which reported the bill favorably the next day, and sent it to the Senate floor for debate.

But Professor Waldo had “coached” (as he later put it) a number of key Senators on the bill, so this time its reception was different.  According to an Indianapolis News report of February 13,

…the bill was brought up and made fun of. The Senators made bad puns about it, ridiculed it and laughed over it. The fun lasted half an hour. Senator Hubbell said that it was not meet for the Senate, which was costing the State $250 a day, to waste its time in such frivolity. He said that in reading the leading newspapers of Chicago and the East, he found that the Indiana State Legislature had laid itself open to ridicule by the action already taken on the bill. He thought consideration of such a propostion was not dignified or worthy of the Senate. He moved the indefinite postponement of the bill, and the motion carried.

As one watches state governments around the U.S. enacting similarly nonsensical, unscientific legislation (e.g., here… perhaps legislators went to school on this), one might be forgiven for wondering “Where’s Waldo?”

 source

Written by LW

February 5, 2013 at 1:01 am

Firing blanks…

 

Since the early 70s, academics and NGOs concerned with population growth have understood that the single most effective “lever” a society can pull to achieve population “control” (short of authoritarian birth bans, a la China) is the enhancement of women’s roles in the economy and society– the better educated, the more engaged a country’s women, the lower its fertility rate– and almost always, the more robust its economy, the more stable its polis, the healthier its environment, etc., etc. [c.f., e.g., here].

While experience continues to support this understanding, research is also suggesting that there may be another, complementary force at work; Pacific Standard reports that “French Semen Is Not What It Used To Be.”:

French men are losing sperm, and not in the fun way, according to a new study in Human Reproduction. Researchers examined semen samples given by 27,000 French men at fertility clinics, and found that the average sperm concentration fell more than 32 percent between 1989 and 2005.

Those findings echo a growing heap of research going back to the 1970s suggesting that the semen quality of men in industrialized countries is steadily declining. The most commonly-cited explanation is chemicals in the environment. Bear in mind, though, the supposed sperm-concentration drop is not a settled matter – many of the studies over the years were poorly designed, had overly-small sample sizes or were otherwise flawed. But if the ranks of men’s sperm are being thinned, for whatever reason, it could have serious implications for couples’ chances of conceiving.

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As we ponder potency, we might send biological birthday greetings to Erasmus Darwin; he was born on this date in 1731.  Erasmus was an accomplished doctor (he declined an offer to be personal physician to Charles III), but is better remembered as a key thinker in the “Midlands Enlightenment”– a founder of the Lunar Society of Birmingham and author of (among other works) Zoonomia, or, The Laws of Organic Life, which contained one of the first formal theories of evolution… one that foreshadowed the theories of Erasmus’ reader– and grandson– Charles.

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Written by LW

December 12, 2012 at 1:01 am

Names to all cattle, and to the fowl of the air, and to every beast of the field…

 

A murder of crows

From E.O. Wilson’s Encyclopedia of Life, via the TED Blog, a collection of very amusing (and altogether appropriate) animal group names: “Animals that travel in schools, towers, bloats and more.”

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As we noodle on nomenclature, we might send dynamically-evolved birthday greetings to Stephen Jay Gould; he was born on this date in 1941.  One of the most influential and widely read writers of popular science in his generation (e.g., Ever Since Darwin, The Panda’s Thumb), Gould was a highly-respected academic paleontologist, evolutionary biologist, and historian of science.  With Niles Eldridge, he developed the theory of “punctuated equilibrium,” an explanation of evolution that suggests (in contrast with the gradualism that was prevalent until then) that most evolution is marked by long periods of evolutionary stability, which are interrupted– “punctuated”– by rare instances of branching evolution (c.f., the Burgess Shale).

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Grandad?!?!?…

Humankind’s remotest relative is a very rare micro-organism from south-Norway. The discovery may provide an insight into what life looked like on earth almost one thousand million years ago… “We have found an unknown branch of the tree of life that lives in this lake. It is unique! So far we know of no other group of organisms that descend from closer to the roots of the tree of life than this species. It can be used as a telescope into the primordial micro-cosmos,” says an enthusiastic associate professor, Kamran Shalchian-Tabrizi, head of the Microbial Evolution Research Group (MERG) at the University of Oslo…

Life on Earth can be divided up into two main groups of species, prokaryotes and eukaryotes. The prokaryote species, such as bacteria, are the simplest form of living organisms on Earth. They have no membrane inside their cell and therefore no real cell nucleus. Eukaryote species, such as animals and humankind, plants, fungi and algae, on the other hand do.

The family tree of the protozoan from the lake starts at the root of the eukaryote species.

“The micro-organism is among the oldest, currently living eukaryote organisms we know of. It evolved around one billion years ago, plus or minus a few hundred million years. It gives us a better understanding of what early life on Earth looked like,” Kamran says…

More– including how newly-developed techniques in genetic analysis enabled the “decoding” of the organism, first discovered in the mis-Nineteenth Century, and how the protozoa might be useful in purifying drinking water– in this article in Science Daily.

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As we marvel at the miracle of mutation, we might recall that it was on this date in 1887 that “Buffalo Bill’s Wild West Show,” including “the selected representatives of several nations, including the Sioux, the Cheyennes, and the Pawnees,” sharpshooter Annie Oakley, and  Colonel William F Cody– Buffalo Bill– himself, opened in London.  As The (London) Times reported:

Its great object is to illustrate the wild life of the Western frontier–its Indians and cowboys, its buffalo-huntings and cattle-ranches, its pioneering and its horsemanship, its dangers and its joys.

And so, for nearly a year, it did.

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