(Roughly) Daily

Posts Tagged ‘biology

“Life’s a little weird”…

Needs must…

You may have ridden out the pandemic in compact living quarters without, say, much natural light or air conditioning. Perhaps you lived with roommates or family in an atmosphere that, as time wore on, grew increasingly toxic. 

Things could be worse! You could be a member of the Alviniconcha species—specifically, a small, spike-studded snail who thrives in an environment inhospitable to most aquatic life; mere meters from deep-sea hydrothermal vents that constantly spew toxic chemicals into the water. Think you have limited natural light? Try living nearly 10,000 feet below the surface of the ocean, where complete darkness envelops you 24 hours a day, under pressure so intense all the air pockets in your body would instantly collapse. 

And forget Seamless. Forget food—at least the kind you ingest with your mouth. Your survival hinges on bacteria living in your gills (you have gills!) in a symbiotic relationship that provides you with energy, via a process called chemosynthesis. It’s like photosynthesis, but chemosynthesis is driven by chemical reactions instead of light. As there’s no sunlight and minimal oxygen present, the bacteria that dwell within Alviniconcha use hydrogen and sulfur molecules to produce sugars and other macronutrients that the animals then use as food. “There’s very little food so deep in the ocean,” says Dr. Corinna Breusing, postdoctoral researcher at the University of Rhode Island and co-author of a recent paper on the snails and their symbionts. “Having your own food-producing machine is much better than waiting for it to fall to you.” While chemosynthesis is common around hydrothermal vents, it can occur in places outside of vents, such as in cold seeps and whale falls and even salt marshes: anyplace the proper mélange of inorganic compounds is brewing. 

The researchers studied Alviniconcha living at the bottom of the Lau Basin, in the southwestern Pacific Ocean, and found that the type of bacterial symbiont determined where their particular host species could live. “The symbionts have different metabolic capacities and adaptations, so we think that the symbionts influence the distribution of the animal,” Breusing says, adding that snails with Campylobacteria dominated at vents with higher concentrations of sulfide and hydrogen, while those with Gammaproteobacteria were able to thrive at sites with lower concentrations of sulfide and hydrogen. Meaning: your chef-roommate, who happens to live in your respiratory system, also decides where you hang your hat (so to speak).

Most hydrothermal vent-dwelling animals, such the aforementioned snails and deep-sea anemones, as well as some species of mussels and tube worms, depend on bacteria that they pick up from the environment, but there is a species of deep-sea clam that passes their symbiont down from mother to offspring, like a fancy set of dinner plates. (This is rare in the marine world, Breusing says.) In the case of the deep-sea clams, where the symbiont is inherited, the symbiont cannot thrive outside the host and dies with it. But if a symbiont is taken up from the environment, it can be released back into the environment after its host dies, ready to help feed a brand-new host.

Alviniconcha might not pack the same visual punch as much marine life does much closer to the surface, but their very existence points to the origins of life on Earth. Before oxygen was free and plentiful, microbial life had to work with inorganic compounds like methane and ammonia, which over millennia dissolved into the seas. Much is still murky about how these little snails co-evolved with the bacteria that enable them to survive, but these fascinating ecosystems indicate that our education about life at the margins is just getting started…

Life at the Edge of Impossible“: ten thousand feet under the sea, these snails thrive with a little help from their friends; from Adrienne Day (@adrienneday).

* Dr. Seuss

###

As we examine extremes, we might send redefining birthday greetings to Carl Woese; he was born on this date in 1928. A microbiologist and biophysicist, he made many contributions to biology; but he is best remembered for defining the Archaea (a new domain of life).

For much of the 20th century, prokaryotes were regarded as a single group of organisms and classified based on their biochemistry, morphology and metabolism. In a highly influential 1962 paper, Roger Stanier and C. B. van Niel first established the division of cellular organization into prokaryotes and eukaryotes, defining prokaryotes as those organisms lacking a cell nucleus. It became generally assumed that all life shared a common prokaryotic (implied by the Greek root πρό [pro-], before, in front of) ancestor.

But in 1977 Woese (and his colleague George E. Fox) experimentally disproved this universally held hypothesis. They discovered a kind of microbial life which they called the “archaebacteria” (Archaea), “a third kingdom” of life as distinct from bacteria as plants are from animals, Having defined Archaea as a new “urkingdom” (later domain) which were neither bacteria nor eukaryotes, Woese redrew the taxonomic tree. His three-domain system, based on phylogenetic relationships rather than obvious morphological similarities, divided life into 23 main divisions, incorporated within three domains: BacteriaArchaea, and Eucarya.

source

source

“Poetry is the art of creating imaginary gardens with real toads”*…

Olivia Fanny Tonge , A Toad, c. 1905

Before the swallow, before the daffodil, and not much later than the snowdrop, the common toad salutes the coming of spring after his own fashion, which is to emerge from a hole in the ground, where he has lain buried since the previous autumn, and crawl as rapidly as possible towards the nearest suitable patch of water. Something – some kind of shudder in the earth, or perhaps merely a rise of a few degrees in the temperature – has told him that it is time to wake up: though a few toads appear to sleep the clock round and miss out a year from time to time – at any rate, I have more than once dug them up, alive and apparently well, in the middle of the summer.

At this period, after his long fast, the toad has a very spiritual look, like a strict Anglo-Catholic towards the end of Lent. His movements are languid but purposeful, his body is shrunken, and by contrast his eyes look abnormally large. This allows one to notice, what one might not at another time, that a toad has about the most beautiful eye of any living creature. It is like gold, or more exactly it is like the golden-coloured semi-precious stone which one sometimes sees in signet rings, and which I think is called a chrysoberyl…

From George Orwell (in 1946): “Some Thoughts on the Common Toad.” From The Orwell Foundation, via Berfrois.

* Marianne Moore

###

As we appreciate amphibians, we might we might recall that it was on this date in 1913 that cartoonist John Randolph (J.R.) Bray first exhibited his animated film, “The Artist’s Dream” (later retitled “The Dachshund and the Sausage” for reasons that will be obvious).  Bray was not the first animator; indeed, he was following purposefully in the steps of fellow cartoonist Windsor McCay, who had added animations of “Little Nemo” and “How a Mosquito Operates” to his stage presentations.  But Bray earned a place in the history of the art by being among the first– arguably the first– animator to organize his work and his studio according to the principles of industrial production (that’s to say, with division of labor)– an approach that has survived to this day.

Bray

 source

“I like it when a flower or a little tuft of grass grows through a crack in the concrete. It’s so f#@kin’ heroic.”*…

From dilapidated power plants, abandoned medical facilities, and amusement parks left in rusted ruin, the compelling scenes that French photographer Jonathan Jimenez, aka Jonk (previously), captures are evidence of nature’s endurance and power to reclaim spaces transformed by people. Now compiled in a new book titled Naturalia II, 221 images shot across 17 countries frame the thriving vegetation that crawls across chipped concrete and architecture in unruly masses.

This succeeding volume is a follow-up to Jonk’s first book by the same name and focuses on the ways the ecological crisis has evolved during the last three years. He explains the impetus for the book in a statement:

On the one hand, the situation has deteriorated even further with yet another species becoming extinct every single day. Global warming continues and has caused repeated natural catastrophes: floods, fires, droughts, etc. On the other hand, our collective awareness has widely increased. We are still a long way from the commitment needed to really change things, but we are heading in the right direction. Millions of initiatives have already emerged, and I hope that my photos and the message contained within them can play a small part in the collective challenge facing us all…

More at “Nature Resurges to Overtake Abandoned Architecture in a New Book of Photos by Jonk” and at his site.

On an apposite note: “Forest the size of France regrown worldwide over 20 years, study finds.”

* George Carlin

###

As we inspect the inexorable, we might spare a thought for Hugo Marie de Vries; he died on this date in 1935. A botanist, he introduced the experimental study of organic evolution– and was, thus, was one of the first geneticists. His rediscovery in 1900 (simultaneously with the botanists Carl Correns and Erich Tschermak von Seysenegg) of Gregor Mendel’s principles of heredity and his theory of biological mutation, though considerably different from a modern understanding of the phenomenon, resolved ambiguous concepts concerning the nature of variation of species that, until then, had precluded the universal acceptance and active investigation of Charles Darwin’s system of organic evolution.

He suggested the concept of genes and introduced the term “mutation”, and developed a mutation theory of evolution.

source

“To be overly concerned with the original materials, which are merely sentimental souvenirs of the past, is to fail to see the living building itself”*…

The human body replaces its own cells regularly. Scientists at the Weizmann Institute of Science in Rehovot, Israel, have finally pinned down the speed and extent of this “turnover.” About a third of our body mass is fluid outside of our cells, such as plasma, plus solids, such as the calcium scaffolding of bones. The remaining two thirds is made up of roughly 30 trillion human cells. About 72 percent of those, by mass, are fat and muscle, which last an average of 12 to 50 years, respectively. But we have far more, tiny cells in our blood, which live only three to 120 days, and lining our gut, which typically live less than a week. Those two groups therefore make up the giant majority of the turnover. About 330 billion cells are replaced daily, equivalent to about 1 percent of all our cells. In 80 to 100 days, 30 trillion will have replenished—the equivalent of a new you…

Our Bodies Replace Billions of Cells Every Day: “A New You in 80 Days.”

* Douglas Adams, Last Chance to See

###

As we sail on the Ship of Theseus, we might spare a thought for Hans Ernst August Buchner; he died on this date in 1902. A bacteriologist, he was a pioneer in the field of immunology, the first to discover a substance in blood, gamma globulins, natural bactericides capable of destroying bacteria.  He also worked with his brother Eduard Buchner, a chemist who won the Nobel Prize in 1907 for his work on fermentation (which helped pave the way for our understanding of the work of enzymes); Ernst had died in 1902, and so did not share in the honor.

source

“He was a killer, a thing that preyed, living on the things that lived, unaided, alone, by virtue of his own strength and prowess, surviving triumphantly in a hostile environment where only the strong survive”*…

One notes that there are only three states with unique predators: two with apex predators– Alaska (the polar bear); Florida (the crocodile)– and Hawaii (the domestic cat). A ‘o ia!

The largest land predators in each state. (TotH to @simongerman600)

* Jack London, The Call of the Wild

###

As we watch our backs, we might spare a thought for Alexander Emmanuel Rodolphe Agassiz; he died on this date in 1910. Following in his father‘s footsteps, he made important contributions to systematic zoology, serving as curator of Harvard’s Museum of Comparative Zoology (1873-85), which was founded by his father.

source

Written by (Roughly) Daily

March 27, 2021 at 1:01 am

%d bloggers like this: