ON OUR DOG’S SENSE OF SMELL

Canine olfaction evolved over 40 million years to an exquisite level of sensitivity. 

 February of 2021 was a snowy month. On the 14th we experienced one of the biggest snow storms in quite a few years. That one dropped about 8 inches of the fluffy white stuff to make the world look like a Currier and Ives print. .  We had barely shoveled that one away, when a few days later, another storm struck, leaving five inches more on top of the older snow. 

On a snowy walk later that day, my terrier Max, his nose quivering and twitching,  excitedly turned from the road to leap up on a pristine snow bank, where about ten feet from the roadway, he buried a good part of his head into the fluffy white stuff.  With his tail wagging happily, Max snorted and puffed as he investigated some “dog-intriguing” aroma deeply buried below the surface. I permitted this activity for a while, empathetic with a “canine, co-shut-in” until, impatient to get on, I pulled him away.  

I was amazed that Max,  on a such a cold day, was able to detect a scent source  buried under five inches of fresh snow, and from a good  ten feet away.  It seemed  incomprehensible to me that volatile molecules— enough to alert Max’s nose— might be arising from a cold snow layer buried so deep.  But there seems no other explanation. 

Though Max’s scenting prowess is “nothing to sniff at” one needn’t search long to learn of many even more amazing examples of a dog’s magnificent scenting ability.  Beagles will bay and follow the scent of a cottontail many days old, over snow and even dusty dry ground.   St Bernard’s routinely sniff out people buried  under tens of feet of avalanche snow in the Alps. “Sniffer dogs” at all our airports are regularly employed to detect the scent of contraband drugs or even explosives hidden in closed and sealed luggage. Then there are examples of dogs being able to  detect human diseases or drug use in minor variations in the scent of a subject’s perspiration.  

How do they do it? 

In  both man and dog, olfaction (or the sense of smell) occurs when certain molecules in the air are carried into the back of the nose where they are detected by receptor cells found in the nasal cavity of humans and other mammals.   

Researchers  have determined that humans  may have  thousands  of receptors far back in our nose. This area is lined with mucous membranes, into which air born molecules settle and are detected by microscopic nerve endings called “cilia” which transmit an impulse directly to the brain.  A part of the brain (the olfactory lobe)  processes the neural message and recognizes the signal as: “Oh that’s the smell of a Christmas tree”, or a rotten egg, or cut grass...etc.   

The olfactory bulb of the brain sits directly behind the nose in mammalian crania and permits odor reception to go directly to the brain—the only sense that does that.  Other senses like touch and vision send impulses through the spinal cord first,  then to the brain.    So smell is immediate and many times more sensitive than other senses such as taste and touch.   

Smell has powerful emotional and instinctive components. The olfactory lobe is directly  connected to a very primitive part of the brain (Limbic System) which controls instincts, emotions and memory.  So smells can almost immediately elicit emotional, sexual, physiological, and  instinctive responses.  For  examples the odor of woodsmoke might brings back the intense memory of a childhood camping trip..on which you fell and were injured. The response to the scent of woodsmoke may elicit a sharp memory of those events, but at the same time elicit anxiety, a rise in heart beat, and higher blood pressure.  Or the aroma of a perfume may bring forth the memory of a fond friend.  Other smells may cause fright or anxiety that are not consciously controlled.  

A dog’s nose works pretty much the same way, but (thankfully) are very different in appearance than ours.  Their noses are generally rough surfaced, black, cool to the touch,  and have those distinctive  slits on the side, and they are almost always moist.  These external differences are compounded internally and in functionally as well. 

The canine’s sense of smell is well known to be many many times more sensitive than our own.  This ability must have evolved over 40 million years ago when the first canids appear in North America—(long before early  humans arrived in Africa  @ 2 million years ago).   Over those many tens of millions of years of  evolution they developed a highly sophisticated sense of smell as key to insure their survival.

One reason why a dog’s sense of smell is so much greater than ours is that canine nasal passages contain  300 million olfactory receptors, while we have only about six million  (thus dogs have 50-times the reception capacity we have).  Furthermore, recent research has indicated that each receptor can detect many different odor molecules.  Canid receptors may be able to detect many more than ours, so  the number of odors a dog may be able to identify are many, many times greater than the “fifty times greater” number  seems to indicate.   

But more importantly, the part of the brain in dogs which  analyses odor molecules —the olfactory lobe—-is also about 40 times bigger than ours.  On those two bases alone their sensitivity is greater by a factor is 2000  alone  ( 50 x 40 = 2000).  But there is more.  

Besides the obvious external differences (our noses are smaller and directed down over our chests, while a dog’s nose is clearly more prominent  with its nasal opening directed right out front)  the inner workings of the dog  nose differs too.  

We breathe in and out through the same passages our nostrils.  In dogs, inhaled air is directed to the sensitive olfactory lobe by a flap of tissue in its nasal passages,  while the exhaled air (with no new scent) is directed out by way of the prominent slits on the sides of a dog’s  nose.   Thus a dog’s nasal passages have evolved to  receive a continual flow of fresh “new “ air over the sensitive olfactory area.   Furthermore, dogs can detect which nostril  (right or left) is receiving the more concentrated scent. It can then turn its head into that direction to seek confirmation of direction and determine where the scent is more concentrated. 

One more recent discovery is that dogs (and other canids, like wolves, coyotes and foxes) can detect infrared radiation, (or heat) with their noses. Snakes are well known to be able to detect this form of radiation. This ability may help explain how a fox or a coyote can detect voles, moles and mice under cover of leaf litter or even under snow.. 

Furthermore, “smell” for dogs is a much more interesting and pleasurable sensation than it is for humans.  Dogs are instinctively attracted to new odors or aromas  Veterinary olfactory specialists call this facility “neophilia”, (Greek “ lover of the new”) or being attracted to new odors.  . ( See “How powerful is a dog’s nose?”,  Phoenix Veterinary Center,  04-23-2020– phoenixvetcenter.com)

The result of all these wonderful adaptations  is that dogs sense of smell is enormously more sensitive than ours and even better than advanced instruments designed to detect odors.  It is claimed that dogs can detect substances in concentrations as low as  one part per trillion. (1: 1,000,000,000,000) or one drop of liquid in “20 Olympic sized pools”. ( See “How powerful is a dog’s nose?”,  Phoenix Veterinary Center,  04-23-2020– phoenixvetcenter.com)*  

Our dogs live in a world of scents that we can hardly imagine.  It provides them today with a complex, rich, multi-sensation of the world around them.  Their vision is as acute or better than ours, but besides vision they have a second sense as acute as vision which reveals to them a vast world of information mostly hidden to us.  And which provide a huge amount of additional information about their environment. 

This ability of scent has been central to their survival, and was a key element in the development of the symbiotic relationship with humans, all of which has also contributed to making them so successful as pets and companions. 

My childhood dog Kim, often found the aroma of the cow flop of certain heifers in a neighbor’s pasture so interesting and pleasurable that he would roll himself  into the soft brown stuff to create a kind of mushy saddle. This behavior made him “tail wagging” happy to carry this wonderful odor along with him wherever he went that whole day. He was also eager to share these aromas with his human friends.  But understandably, when he turned up at the back screen door begging to come in for his supper, he was barred. 

Then it was his best friend who was assigned the dirty task of garden hosing the big dog down.   His “wet dog shake” had to be carefully avoided on these occasions, or a boy’s carelessness  would result in both dog and boy being banished from supper. 

[* I calculate the ratio is one drop (20 to a ml) of scent to  25 Olympic pools. ]

THE SHORT TAILED WEASEL ON LONG ISLAND

 Long Island’s Smallest Most Vicious Carnivore

What is a weasel? Someone asked me that question recently....and I knew the answer.   Though having seen one close up in the wild only once and many many years ago. 

My experience was more than a half century  old, but the memory remained so vivid I can clearly  recall it today.  So it is with our wildlife experiences.  They are often just chance encounters, fleeting moments cherished in one’s  memories and hardly ever recorded.  So here I remedy that failing and recount a tale of long ago and perhaps, my earliest observation of an important Long Island  mammal, and our smallest Long Island carnivore.  

The Short Tailed Weasel ( Mustela erminiea)  is a member of the Order Carnivora, and Family Mustelidae —which includes weasels, skunks,  the wolverine and the otter.  The short tailed weasel is is a smaller species (about 11 inches long) and  more northern species than its closest relative the long tailed weasel M frenata (about 16 inches long).  The short tailed is known to have been reported from Long Island  (Babylon in 1949) but it is rare here.  In fact in my many years of field work,  I have never again seen this small weasel which  turns all white in winter and is known also as an ermine! 

This event occurred in the post war years of western Suffolk County, in the Town of Smithtown, just outside of the village of Kings Park, where as a young child  I made my first animal observations. 

It was a lovely early morning July day in 1948. My grandfather’s home in Smithtown, was our family refuge from the seasonal  (summer long) plague of polio ravaging the boroughs of New York.  In those days Long Island was still dominated by agriculture and  barely changed from its late 19^th century character. My grandpa’s  house had no electricity and no town water.   Grandpa trimmed the wicks and lit the kerosene lamps each night, and in the morning we hand-pumped ice cold  water from a deep 120 foot well. We  all had to use the outhouse and deal with bedroom potties we slid under our beds each night.  The roads were surfaced with clean yellow sand, where youngsters of eight and ten years old, could walk barefoot all day, and did so happily!  And  where one day each week the ice man came to chop out a block of ice ( for grandpa’s ice box) and in the process create  all those dark gray ice chips that fell to the sand and in kid’s hands melted into drippy ice and cold water for a kid to hold and slurp on a hot summer day. 

On that summer day which was to become the “ weasel observation day” my cousins and I  were on our way to the “Bluff” a half mile walk to the Nissequogue River where the older kids would swim and fish with hand lines and  youngsters could splash in the river and loll on the warm sand.  

Our path that day took us to the end of grandpa’s road,  past land which had been cleared a few decades ago, and now grew  thick with oak brush, staghorn sumac  viburnum, elderberry, blackberry and sweet fern,  and the ubiquitous dense growths of dark green, luxuriously growing, oily-leaved poison ivy.  The newly cleared land and varied growth had created  an environment which was rich in species of plants, and animals. It was a good place for weasels which have to consume a good part of their own body weight in meat each day just to survive. 

Our barefoot threesome, one encumbered with a tomato can of rusting  fishing gear ( a few rusty flounder hooks, some lead weights,  and lengths of tarred cuttyhunk  line), the other boy with a towel over his shoulder recently plucked off Aunti’s clothes line, and me, I was assigned to carry the sweating jug of cold pump-water lemonade.  But no cups!. 

A mere 200 feet along on our journey we walked along the sturdy white post and rail fence enclosing  our neighbor—fastidiously neat— Mr Ferstakski’s property,  I stopped.  There right out in the open in  the corner of recently cut lawn, sparkling with morning dew, a baby Eastern Cottontail Rabbit  (Sylvilagus floridanus) sat happily  nibbling the fine tender stems of Mr. Ferstakski’s well-tended lawn. 

I shifted the jug from one hand to the other to point at the cute little critter.

“Look a bunny,” I called..

The others stopped too.  The  little furry fellow seemed oblivious of us..  He looked our way seemingly assured we posed no mortal danger.  (though the two elder members of our threesome were known to carry “Tom Sawyer” style sling shots in their back pockets).  The  little cottontail twisted his ears around in our direction and looked up with big brown innocent eyes, while a green stem of  Mr. Ferstakski’s  grass slowly disappeared into his bewhiskered nibbling jaws. 

But this bucolic calm and serenity  was shattered in an instant when, when with a faint rustle of brush from the far side of the sandy road and a flash of brown, a  “varmint” about the size of a very small squirrel, looking much like a  brown tube on short legs, dashed out  from the thicket of staghorn sumac and  poison ivy.  With several  looping bounds, it crossed the road within a few yards of our bare feet,  Ignoring our exposed flesh , it raced under the lower post of the rail fence—to streak toward  the baby bunny.

The weasel was on its victim in an instant. It raised its long body onto its hind legs to attack the bunny’s head. Its lower body formed a rigid  “L” with  hind feet  braced and its front paws tightly grasping the head of the rabbit. Then it arched its neck  as it bit into the back of its now struggling prey.  

The bunny let out a piercing scream.  It struggled to escape from the  grasp of its  tiny attacker, smaller than it.  The lithe, slim weasel was focused only on its prey and seemed oblivious of all except the object of its attack  which it seemed so single mindedly  determined  to kill. 

“ It’s a weasel, a blood suckin’ weasel”  the boys yelled  in unison. 

I stood stock still, shocked by the violence of the attack as I watched  the struggling  bunny, twisting and staggering back in a vain attempt  to throw off its attacker. My bare feet were cemented  into  the road sand.  The two older boys yelled and dashed toward the fence and the site of bloody carnage.  From where I was standing  I could clearly see the weasel..  It was small,  maybe only ten or twelve inches long,  it had a coat of brown fur above and had a white belly and its tail was short and brown.  

As I watched,  one of the boys ducked under the fence and raced up  close enough so that the  predator,  at first so focused on its prey turned from biting the bunny’s neck.  It stared at the approaching boy for only a split second.  Perhaps assessing the threat of this perhaps unseen element charging toward it with pounding feet.  It released its grip on its now wobbly prey, to turn  and dash off into the thick brush bordering the Ferstakski’s lawn. It disappeared as quickly as it had appeared. 

The bunny, bleeding from the base of one of its long ears  staggered around as if in a daze, seemingly unable to escape,  and yet still standing.  One of my cousins reached out and picked him up.

“His heart’s beating so fast,” he said. 

“Yours would be too, if you got blood sucked by a weasel”, said the other. 

“Robbie, come on over here and see this,” they called,  as the older boy, gently put the bunny to the ground. 

We all  stood still to watch it.  It remained motionless for a few seconds and then with one ear flopped  over and dripping blood  it bounded off toward the  Ferstakski’s  vegetable garden from where it must have come. 

“Well,  we saved that bunny from a blood sucking weasel¨ , they said. 

 Only many years later did I learn more about these tiny carnivores belonging to the group of mammals called  mustelids to which the little short tailed weasel belongs.  And learned too that they don’t “suck blood”—but are pure carnivores needing to kill regularly every day.  And perhaps made a rare observation of a species now considered rare or extirpated from Long Island.  

 

ARCHAEOPTERIS THE TREE THAT CHANGED THE WORLD

A DISSERTATION ON THE FIRST TREE. 

ARCHEOPTERIIS A TREE, THAT CHANGED THE WORLD SO MUCH IT LED TO ITS OWN EXTINCTION  

The first fossil I ever found was that of a fern. I am not sure what species.  I remember it so well. I was on a field trip in Pennsylvania and there at the foot of a road cut among  a lot of other rocks I picked up a cobble of  red shale. I hit it with the chisel edge of my geologist’s hammer and the rock split apart neatly,  along a bedding plane or weakness in the rock.  There, exposed for the first time in perhaps hundreds of millions of years was the gray, iridescent imprint in a thin carbon film of a fern—a fossil.  It was dark gray—all that was left of the fern was the carbon that made up its atoms— but the carbon “print” was arrayed just as it had been perhaps 300 million years earlier. And every little detail was visible, even the tiny hairs on the stem and leaflets. 

Archeopteris is an extinct genus of primitive tree known only by its fossil remains. It’s leaves were fern like similar to the fossil fern I found so many years ago. This fossil tree -which looks like a Christmas tree—has characteristics of both ferns and conifers.  It lived late in the Devonian period some 380 to 320 million years ago (mya). 

It’s arrival on the scene was a watershed event that forever changed the entire Earth...its atmosphere, is rocky skin,  and the life-forms which lived on its surface.  Then, It quickly became extinct.  It changed the Earth environment so extensively that it “found itself” no longer well adapted to the new ecosystem it created.  It was source of its own extinction 

In the Cambrian , Ordovician, and Silurian of the earth’s near 600 million year history of life, most of the attention of scientists was focused on the fascinating evolution of the invertebrates, brachiopods, corals and reef organisms, while in the Devonian much interest was focused the  bizarre fish which appear in the world’s  oceans at that time.. During most of the Devonian period there was not much happening on land. 

At that time our present continents were not what they look like today, or were even where they are today.  North America was much smaller than at present and  far south of where it is located today.  During the Devonian, what would become North America was much closer to the equator.  Thus  the Devonian climate was much warmer and drier too than it is now.  (Recall that continents drift around on the Earth’s surface to collide  together to produce mountain chains then break apart again in @ 500 million year cycles). 

What is now our present east coast, was then dominated by high coastal mountains. The deep Atlantic did not exist off our east coast shore, there a shallow sea separated early North America from  a line of offshore volcanic islands ( similar to modern day Japan and the Philippine Islands).  Farther away,  to the southeast was another large continental mass called Gondwana.  Gondwana was moving slowly toward North America with which it would collide to form new mountain chains at the suture line,  at the end of the Paleozoic, as it  formed  a super continent called Pangaea. 

The floating continents or land masses themselves were rugged, rocky highlands, with very little or no vegetation. These bare rocky lands were exposed to driving rain, which unhindered by vegetation or water absorbing humus and soil, scoured out deep gullies and drainage channels. The tropical rains must have produced mud flows and earth slides which would have roared down mountains and accumulated in lowlands as muddy barren outwash or fluvial deposits. The earth’s surface  was also exposed to a relentless intense sun. Exposure to heat and cold, to air and water physically and chemically decompose rocks into clays, oxides and other chemical  products which lay on the surface subject to transport down slope by the first heavy rains . These critical mineral elements necessary for plant nutrition  were washed downhill into rivers and into the oceans by surface water. The early and middle Devonian landscape was a hellish place with little greenery, no bugs, no bees, no animals—no shade, and no forests.   

The land of North America during the early part of the Devonian did have some land plants—these were rock encrusting green algae, lichens, ,and liverworts, while club mosses and horsetails were low growing vascular plants that did not have true leaves and reproduced by spores. Ferns occur as well, but  plants did not grow more than a meter high.  The Devonian ferns grew as they do today in moist places close to water sources. The highlands, away from permanent water were barren and without significant vegetation.   There were no flowering plants or seed bearing plants. 

Early in the Devonian, atmospheric oxygen levels were much lowe as a a result of no forests with their layered concentration of green leaves to effectively produce oxygen by photosynthesis from carbon dioxide and water,  Oxygen  perhaps comprised only 17% of the atmosphere (present day oxygen is now at 21%)     Carbon dioxide levels were correspondingly higher too...about 0.3% or @ ten times higher that what we have at present  ( present CO2 comprises  about 0.03%). 

But all this was to change rapidly as the end of the Devonian Period approached, for a new plant was to evolve that changed the entire Earth, its atmosphere, its oceans and almost all living things as well.  This new species -a tree—created new environments, new ecosystems into which new organisms would eventually adapt. Thus it helped diversify all the life on earth, even though it lived only a brief time, in geologic terms, from 380 mya to 320 mya then became extinct. 

The history of how Archaeopteris was discovered is interesting and informative as well.  The first paleontologist to describe  Archeopteris  was John Dawson (1871) who recognized it as an ancient fern and coined the genus name “archeopteris” which is from the Greek, and means: “ancient fern” (αρχαιος = ancient , πτερις = fern).  For to the early paleontologists the leaves  looked just like that of a modern fern—but one that lived nearly 400 million years ago  (380 mya). 

Dawson’s genus name “Archeopteris”  made sense at first—it seemed to be a fern. About  forty years later a Russian paleontologist, Mikhail Zelessky (1911) examining the stumps of fossil petrified trees in a the Ukraine described what he considered a new kind of ancient tree i that he found in Devonian strata. He considered it unusual since the wood tissues showed characteristics of the wood of conifer trees such as spruce and pine. He called this “new species” Callixylon (also of Greek origin. It means: “good wood”).   He did make note of the fact that this new genus of plant was often associated with the “fern” Archeopteris. 

But it was another fifty years later (1960) that Charles Beck also studying Devonian plant fossils came across specimens of Callixylon which had small side branches with the fronds and leaves of  Archeopteris attached to it. It was clear that Archeopteris and Callixylon were parts of the same plant.  [So perhaps had Dawson seen these samples, he may have named the genus “archeodendron” or “ancient tree” instead. But that is how science proceeds- only in fits and starts.]

But what was so unusual about this new plant fossil was that it had characteristics of both ferns and conifer trees. It had fern-like leaves and branches which carried “sporangia” which the sites where spores were produced just like ferns.  Archeopteris, unlike ferns, had spores of of two types: a male and female form, perhaps a precursor to the conifers which produce pollen and cones. Also this tree had a tree trunk with vascular tissues or  wood  just like those of the evergreen or gymnoperms (the cone bearing trees —the conifers, ginkos, and cycads—) of today. 

 

This now extinct tree Archeopteris looked  like a top-heavy “Christmas tree”, but it’s branches were fern like as were its leaves.  It had  a “real” woody tree trunk.  The bole of some petrified specimens  had grown to three to five  feet in diameter and to a height of thirty meters (near 100 feet).  It was the first true tree*.  It’s wood in cross section displayed tree rings,  showing spring and summer growth patterns, similar to those of  a pine or spruce.  It had two different sized spores a male and female division not found in ferns.. Archeopteris with its characteristics of  of both ferns and woody trees grew in wet places close to rivers and streams. But could also grow elsewhere.  It had an extensive root system which went deep into the earth. In some Devonian sites these fossil roots are still visible. 

From about 380 mya when the tree first appears it dominates the land area and out-competed every other species to  very quickly becomes the dominant tree all over the Earth.  Its wide and very rapid dispersal and dominance indicates that its ability to grow tall, rising well above the lower plants to form a true forest canopy gave it a tremendous advantage over those plants which had no woody support tissues or the ability  to carry water upward thirty to one hundred  feet to its leaves.  But that is where the unrestricted sunlight was available, and by being able to move its leaves well above all other plants at the time it had a great advantage.  

Wherever trees can exist today the Archeopteris probably lived there. It’s fossils are found on every continent where the Devonian and early  Carboniferous  strata occur, even on Antarctica. 

It almost immediately became the dominant land tree almost all over the world and perhaps because of its widespread distribution, had a greater role than most any other in transforming the environment of the entire Earth.

It’s tall trees grew close together to form the first forests.  The forest itself is a new ecosystem in which new plants and animals were to become adapted.  Its great volume and display green leaves took in carbon dioxide and produced oxygen, raising the concentration  of that gas and likely making the atmosphere more amenable to land animals and to other plants as well. 

Soon after its world wide spread as dominant forest tree,  we find the appearance of the first land animals. These were land arthropods, millipedes, centipede and spiders. Then too the first tetrapods appear late in the Devonian  (four legged creatures) which evolved from relatives of the bony fish such as the coelacanth and lung fishes which evolved more rigid pectoral and pelvic fins making it possible for them and those who evolved later to literally haul themselves out of the water onto nearly dry land. 

The branches and leaves of Archeopteris may have fallen  seasonally as debris which accumulated on the forest floor then washed into streams, and there created a new nutrient rich environment where other organisms would evolve. The new nutrient rich stream and river waters were to attract marine bony fish into the fresh water environment, and  encourage the tetrapods into these new ecosystems as well..  

The canopy produced  by the Archeopteris generated shade that altered the environment on the ground,  making it more amenable to the emerging tetrapods and land animals and the  first insects who were protected from dehydration and intense solar radiation in the shade of the forest.  

The seasonal fall of fronds and leaves formed the first layers of forest litter and humus from which true soils would develop. Decay organisms (bacteria, fungi and eventually  worms) evolved among the millipedes and centipedes in this new environment at the base of the trees.  

After the advent of Archeopteris dominated forests and the soil they created,  rainwater no longer just washed down slopes carrying loose rock and the valuable chemical products of weathered rock, (with its clay and essential  minerals)  because the Archeopteris’ decaying humus held these critical elements in suspension or by adsorption and absorption in the now newly forming soil so that it and other plants could utilize them more effectively.   The humus also held water like a sponge, resulting in this moisture becoming  available to other plants and animals within the soil. 

This first ancient tree had a well developed root system which had an enormous impact on development of soil systems, on slowing erosion, on stabilizing slopes and on creating new ecosystems for other organisms to evolve.   ( At the Gilboa Pertified Forest, near the Gilboa Dam in Schoharie County, New York there are many tree stumps, fossil leaves and fossilized root systems of these first trees exposed for view.) 

At the end of the Devonian, when Archeopteris forests were widely dispersed this species may have even had a role in the great late Devonian extinctions. Some claim its rapid world growth into forming continental wide forests had the effect of reducing carbon dioxide levels in the atmosphere, causing  a global cooling effect.  The fall of global temperatures may have been one (of many) causes resulting in widespread late Devonian marine extinctions.   

[ Extinctions are not all negative events, they have their positive effects too.  Though in extinctions many organisms may die off, the survivors, often better adapted to the new conditions, are able to evolve and take over a food source, unoccupied niche or escape from predation and then—/proliferate. So we might add this result to Archeopteris’ other positive effects.]. 

Others cite extensive volcanism for the Devonian marine extinctions. Such an event could have  caused atmospheric darkening and oceanic cooling. Many black shales are deposited in this period indicating a lack of oxygen in the ocean water. Some suggest the extinctions were the result of an asteroid impact.  Many species of marine invertebrates become extinct during this time.  Trilobites, brachiopods, and reef building organisms were particularly hard hit. Paleontologists claim that  some  50% of all marine genera died out. But there were few impacts to terrestrial organisms. Archeopteris lived on into the Carboniferous so was unaffected. 

The Archeopteris lived from about 380 to 323  mya and then for some reason, it rapidly became extinct.    But while it lived, its leaves and fronds are so common in late Devonian early Carboniferous strata all around the world that it became an excellent marker fossil or index fossil,  used to indicates that the rocks in which it was found are synchronous or of the same age as the  Devonian and Early. Carboniferous strata.  Good index fossils are those that were widely distributed and lived only for short time before extinction.  Come to think of it humans might be —except for being extinct— perfect potential example. 

Perhaps as the result of circumstances it helped to create,  more atmospheric oxygen, less carbon dioxide, true soils, enriched soil nutrients, more stable slopes, etc.,  etc. it was no longer as well adapted to.  In this new ecosystem. Other species that evolved within the forests it created were better adapted and were  able to out-compete Archaeopteris.   

Thus the story of Archeopteris may be a cautionary tale for humans. Archeopteris changed the Earth in innumerable  ways and then quickly became extinct. It was so dominant and so effective in changing the Earth and its environment—it created an Earth so altered that it “found itself” no longer well adapted to the new world it had created, and died out.  Archeopteris  was the source of its own extinction!!

So perhaps we as humans should take note of the history of Archeopteris and beware of the prospect of our own extinction. Because  we too, as a super dominant species have created  a new world, vastly different in atmosphere, temperature, climate, fauna and flora  from that which we emerged as a species and came into prominence about two million years ago.  (This denouement of our own species came after a major extinctions too—that of the Pleistocene megafauna!!)  Have we too changed our environment so drastically and radically that —like Archeopteris—we are too are no longer “adapted” and are slated for extinction? 

Perhaps it’s still not too late. It is time for us to return the Earth closer to conditions that we as a species evolved into and adapted to. 

We might begin this task by reforesting all the areas that we have foolishly deforested over our history—so as to return the CO2 levels back down to lower levels. 

Let’s  all plant a tree. Perhaps we can still save our species and a planet too.