Archive for September, 2011

If I could Live in the Pleistocene Part VI–Top 10 Most Dangerous Animals to Avoid

September 26, 2011

So it’s 36,000 BP, and I’m living in my adobe brick house/mansion/castle,  built on a picturesque spot located 2 miles west of what’s now the Savannah River and 1 mile north of the Broad River.  A time tunnel connects me to the present in case of emergencies, but otherwise I’m living in an area of the world where there are no other people.  In today’s world the only dangerous animals I’m likely to encounter are other humans and their dogs.  Gangsters, twisted bullies, or psychos could assault me at any time, but I lower the risk by staying away from low income neighborhoods.  Dogs are the only other animal to be wary of.  A few years back, I had a neighbor who was freaked out because he saw a rattlesnake which he killed by driving over it.  After this incident he seemed annoyed at me–I had let my garden get a little weedy and he spotted a corn snake in it.  Yet, this snake-phobic honcho always let his pit bull terrier run loose.  Luckily for me, it was only aggressive when I was behind the fence.  It would charge and snarl at me as long as I was in my backyard, but when I went to get the mail the nasty canine would retreat and yelp in terror.  In my Pleistocene world though I have no human neighbors and no pit bulls to worry about.  Instead, there is the megafauna.

Skull of an australopithecus and mandible of a leopard.  A leopard apparently killed this hominid.  The skull has canine marks matching those of a leopard. Big cats hunt apes by attacking them directly from behind.  Man-eating tigers are notorious for attacking humans using this tactic.  It’s an intelligent strategy.  Even a man with a gun would be killed easily.  He’d have no chance to use his weapon.

The walls of my Pleistocene adobe home consist of a double layer of the fat dried bricks.  The windows are high off the ground and have steel bars over them.  I feel safe inside.  I doubt any predator would waste energy trying to dig through the walls.  Likewise, my yard with livestock, a garden, grainfields, and a fruit orchard is surrounded by a high wall designed to make it difficult for animals to climb over.  A safety problem arises, however, when I choose to make forays outside of my fortress.  I use a steamroller to maintain a 3 mile dirt road between the Broad River and a chestnut ridge.  I attend fish traps, and I like to take boat rides.  And I survey plants and animals for scientific data.  These activities take me into the danger zone.  I’d definitely be carrying a Glock.  Here are the top 10 most dangerous Pleistocene animals in this region that would keep me on the alert.

1-4.  The big cats concern me the most.  4 of them are tied for first place–saber-tooths (Smilodon fatalis), scimitar-tooths (Dinobastis serum), giant panthers (Panthera atrox), and jaguars (Panthera onca augusta).  A big cat could sneak up on me and jump on my back before I even knew it was there.  I would have no chance to draw my gun or retreat to my vehicle.  In India tigers learn to kill people by coming at them from directly behind.  Some natives wear masks on the back of their heads–a tactic that confuses man-eating tigers and prevents attacks.  An attack from behind would mean instant death.  Pleistocene big cats in southeastern North America have not yet learned to fear man and might be more likely to attack than not.

5. I rank cougars (Puma concolor) behind the other big cats.  Pleistocene cougars were on average 5% larger than modern cougars and probably considerably bolder, but still they’re a smaller cat that I might be able to box off me, giving me a chance to use my gun.  Nevertheless, if one attacks me from directly behind, I’m in trouble.  This rear-attacking tactic may be learned.  Maybe naive Pleistocene cats would attack humans from the front.  I can only hope this is the case.

Photos from google images of elephants running amok.  The man in the bottom image was killed by that elephant calf.

6-7.  Mastodons (Mammut american) and mammoths (Mammuthus colombi) are in a tie for 6th place.  I believe proboscideans unaccostomed to people would be peaceful animals unless protecting young–a situation easily avoided.  However, when male proboscideans become ready to mate, they go berserk, attacking everything in sight, including other elephants, rhinos, and people.  Even male elephants kept in captivity often go amok.  Although I can see an animal this large approaching, a Glock might be an impotent weapon.  A gunshot might just infuriate it more.  And the great beast could overturn my vehicle, if I manage to escape inside.

I wouldn’t want to face an angry herd of bovines.

8. Long-horned bison (Bison latifrons) were likely very aggressive animals–an adaptive behavioral response to an environment populated with lots of predators.  I should be able to see them from a distance and avoid them.  However, I enjoy eating steaks, roasts, hamburgers, and chili.  If a bison wandered near my adobe home, I might want to shoot it for the meat.  Its companions might hang around or return to protect the carcass.

9. Both black bears (Ursus americanus) and giant short-faced bears (Arctodus simus) could be trouble.  I should be able to avoid these clumsy, noisy animals, but I better be on the lookout.  A gunshot would probably just piss the thick monsters off.

10.  Dire wolves didn’t use stealth, so I think I can avoid a wolf pack.  I wouldn’t want one, let alone a pack, of these hard-biting brutes to get between me and my vehicle.  I’m certain they’d have no fear of a man.  They didn’t learn to fear men until it was too late.

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Pleistocene Bison Wallows

September 20, 2011

Prairie Violet (Viola pedatifida).  Laura Ingalls’s little toddler sister wandered off and was found in an old “buffalo” wallow overgrown with violets–probably this species.

I admire the clear and concise prose of Laura Ingalls Wilder, author of the famous Little House series for children.  Her stories offer a glimpse of life on the frontier before most of the conveniences we think we can’t live without were even invented.  In one of her books (I believe By the Shores of Silver Lake) she recounts an incident that probably was based on a true event.  (Her stories were a blend of fiction and nonfiction.)  This traumatic adventure occurred when Laura was in her early teens.  They were living in a house in the middle of the short grass prairie in South Dakota.  They were miles from any neighbors.  Laura was helping her mother and father plant small trees to form a windbreak for the house.  While toiling, they didn’t notice Laura’s baby sister, Carrie, had wandered out of sight.  After congratulating themselves for doing such a good job on the hedgerow, they experienced the bad shock of realizing the toddler was missing.  The whole family scattered in different directions searching in panic.  I endured that awful feeling once when my daughter got on the wrong schoolbus on the first day of middle school.  That was the second worst day of my life even though her whereabouts were unknown for only half an hour.  Laura eventually found her sister some distance away sitting in an old bison wallow overgrown with violets.  Carrie was amongst the flowers, pulling them, and saying “sweet, sweet.”

It occurred to me that bison wallowing must have had a significant impact on the environment, altering the habitat so that it favored some species of plants and inhibited others.  However, I didn’t think anybody had ever studied such an esoteric subject.  Happily, I was wrong and found a recent study about bison wallowing published in The American Midland Naturalist.

Photo of a bison wallowing from google images.

Bison create wallows when they repeatedly roll and kick their legs in the same area to rid themselves of parasites, to scratch insect bites, and to give themselves a dust bath which may help stymie ticks, fleas, and flies.  The wallowing forms circular depressions with compacted soil where water is retained longer than on adjacent prairie land.  Some wallows are larger than 2 acres.  There were millions of wallows across North America before the extirpation of the bison.  Most have been plowed under but some still exist and are known as relic wallows.  Cattle do not wallow, and accordingly, habitats created by wallows are limited to the few area where bison still exist.

Scientists studied plant diversity at the Konza Prairie Biological Station in Kansas which is owned by the Nature Conservancy and managed by Kansas State.  They compared the kinds of plant species found in active and inactive wallows and adjacent prairie.  They counted a total of 153 species of plants of which 10 were found only in adjacent prairie and 25 were found only in wallows.  Overall though, they found lower species diversity in active and relic wallows than in adjacent prairie.  Bison rolling, compacted soil, and excess moisture is evidentally intolerable to many species of plants.  Here’s a list of the 5 most common species of plants found in each type of habitat.

Inside Wallows……………Adjacent Prairie

1. Western Ragweed………..Big Bluestem

2. Sedges……………………….Heath Aster

3. Canada Bluegrass………..Sedges

4. Ridgeseed Spurge………..Western Ragweed

5. Hoary verbena……………Scribner’s rosette grass

Plant species diversity is also greater in grazed areas than in ungrazed areas.

During the Pleistocene there must have been tens of thousands of bison wallows, some abandoned, some active across the southeastern coastal plain and into the piedmont.  As I’ve noted in earlier blog entries (See https://markgelbart.wordpress.com/2010/06/11/were-there-three-species-of-bovine-roaming-southeastern-north-america-during-the-late-pleistocene/ and https://markgelbart.wordpress.com/2011/08/01/a-probable-pre-clovis-bison-butcher-site-in-washington/), I suspect there were 2 species of bison living in the region then.  The two species may have hybridized in some areas, and the long-horned bison is probably ancestral to the shorter-horned variety.  Long-horned bison (Bison latifrons) and northern bison (Bison antiquus) fossils have been found throughout the south, and they overlap geographically and temporally.  Long-horned bison may have been more of an open forest species, while its cousin may have preferred more open grassland.  Their wallowing behavior created habitats favorable for some species of plants and detrimental to others.  The common plants found inside and outside of Pleistocene wallows in the southeast undoubtedly differed from the list of plants found in the modern tall grass praire.  The composition of plants in Pleistocene bison wallows will likely remain a mystery.

Reference:

McMillan, Brock; Kent Pfeiffer, and Donald Kaufman

“Vegetation Response to Animal Generated Disturbance (Bison Wallows) in Tall Grass Prairie”

The American Midland Naturalist Jan 2011

The Stupidity of Answers-in-Genesis

September 15, 2011

I’m sorry I’m opening this week’s blog entry with a photograph of the republican presidential candidates instead of something like a photo of a giant ground sloth fossil.  Actually, a dead ground sloth would make a better president than any of the big business puppets running for the 2012 presidential election.  Rick Perry, cowboy redneck, will probably be our next president.  Just what we need–another really bad president from Texas.  Some liberals are in panic while other are in denial.  I don’t see what the big difference is between him and Obama.  Obama has been a center right president; Perry will be an ultra-right president.  Whoopee!  That difference doesn’t inspire me to vote.  All the republican presidential candidates with the exception of John Huntsman, who polls less than 1%, professed a disbelief in the science of evolution and anthropogenic global warming, throwing red meat to their mentally-challenged base.

Roughly half of the American people prefer to believe ancient story-tellers over modern scientists.  They think the earth is 6,000 years old and God created it in 6 days and anybody who disagrees with them is an immoral fascist/socialist on the road to perdition.  Yet, if they fall ill, they don’t consult an 11th century physicians manual.  They go running to the nearest modern medical professional.  I suppose if believing in evolution was a life or death decision, there would be more believers.

Recently, all of the real presidential contenders for the republican nomination considered it necessary to profess a disbelief in the fundamental basis of all biological science.  I doubt they honestly disbelieve science.  Instead, they’re appealing to an uneducated segment of society with an unfortunate belief system.  Scientific ignorance has become politically tied to the republican’s other twisted talking points such as cutting taxes, deregulation, and hostility to the government.  Conservatives have so successfully shouted down liberals that democratic politicians also promise to cut taxes, deregulate, and carry on expensive, unnecessary wars of aggression against brown-skinned people, even though those are the policies that created our current economic doldrums.  The U.S. is such a gullible nation.

The Reverend Ken Ham is a snake oil salesman profitting from this gullibility.  He founded the Creation Museum in Kentucky.  He charges $20 admission, but most of the workers there are unpaid volunteers who must sign a vow that they believe in a literal translation of the bible.  In addition to his for profit museum he’s selling ridiculous anti-science propaganda to churches, mostly in the U.S.  He must be raking in millions annually.  When perusing his fodder for the bible-thumpers who want their ignorance reinforced with likeminded rubbish, it doesn’t take long to discover the absurdity of his claims.

Replica of a T. Rex skull fossil.  Ken Ham believes T. Rex was a plant-eater, until Eve convinced Adam to eat the apple.  The first sin is what forced some animals to become carnivores after they were all thrown out of paradise.  One look at a T. Rex’s teeth debunks the claim that it ever ate plants because they’re absolutely unsuited to a plant-based diet.  Some creationists claim the flood caused the extinction of dinosaurs and other prehistoric creatures, but not Ken Ham.  He insists on biblical accuracy, and the bible says Noah put an example of every living animal on the Ark.  It was only after the flood that dinosaurs became extinct, so he insists dinosaurs co-existed with man, at least for awhile, despite the total lack of fossil evidence for the overlap.  And a lack of archaeological evidence as well.  Surely, the natives would have collected T. Rex bones.

One quote from Reverend Ham makes it evident he’s never read a geology textbook.  He stated, “there’s no evidence whatsoever that the world and its fossil layers are millions of years old.”  No evidence?  Why do almost all, if not all, professional geologists believe the world is 4.6 billion years old?  Would they believe that with no evidence?  Here’s a brief summary of the evidence that the earth is older than 6,000 years old.

1. Dendrochronology–shows earth’s at least 10,000 years old.

2. Ice Core data–shows earth’s at least hundreds of thousands of years old.

3. Varves–show earth;s at least’ millions of years old.

4. Coral reefs–one’s 130,000 years old.

5. Astronomers measure the galaxy as 100,000 light years across.  Visible starlight is that old.

6. Rates of Continental drift–suggest earth’s at least millions of years old.

7.  Analysis of the Geological Column which is consistent with the fossil record.  For example part of the Rocky Mountains rests over a massive fossil coral reef that itself took millions of years to grow.  Why would God hide a fossil coral reef under the Rocky Mountains?  No mammal fossils are found in Coal age deposits.  No dinosaur fossils are found in Pleistocene deposits, etc.

8. The radiometric age of some minerals on earth is 4.1 billion years old.

9. The ratio of Lead isotope decay from samples of earth and meteorites is consistent with a 4.6 billion year old earth.

10. The oldest age determination of meteorites are all consistently between 4.4 and 4.6 billion years old.

Creationist arguments against these points mostly consist of either God made it look that way or that scientists base their assumptions on such things as the speed of light and the freezing point of water have always remained the same.  Yes, those are assumptions, but I think they’re pretty safe assumptions.  For the above points to be in error, it would take many drastic changes in the known laws of physics.  Creationists might dispute this evidence, but for Ken Ham to claim there is no evidence whatsoever proves he ignores real science.

One of the biggest fraudulent claims creationists often make is that there are no transitional fossils.  There are literally thousands of transitional fossils.  Because evolution is an ongoing process, all organisms can be considered transitional, but the fossil record also clearly shows a progression of speciation with transitional characteristics.  The fossil record of the horse is a good example, and creationists recognize this and attack the science with many unfounded criticisms.  I found a series of articles written for answers-in-genesis  by a Presbyterian minister who questioned evidence supporting horse evolution.  I believe Peter Hastie wrote all three of the following articles, though he only signed his name to one.  They are: “Horse find defies evolution,” “Horse nonsense,” and “What happened to the horse?”   So we have a case of Presbyterian minister going against paleontologists and vertebrate zoologists.  All three articles consist of falsehoods and gross misunderstandings of evolution.

Artist’s depiction of eohippus, or hyracotherium, also known as the dawn horse.

In “Horse nonsense” Peter Hastie makes the bizarre claim that Eohippus was actually related to the rabbit, not the horse.  As the above artist’s depiction indicates, the dawn horse greatly resembles a horse, not a rabbit.  (He didn’t use a scientific name but he wrote cony which is another common term for rabbit.  Maybe he meant hyrax.  It bares no resemblance to a hyrax either.)  He claims there is no sound evidence linking the dawn horse with the modern horse, but evidentally, professional scientists do, and any layman looking at the picture can see the great similarity.  Hastie also rejects horse evolution because horse fossils are found in different localities.  He claims it is circular reasoning to use horse fossils from different species collected from differenct localities.  He demands a fossil site that shows the entire evolutionary history of the horse in successive stages.  I don’t quite understand why he considers this circular reasoning, but I suppose, if there was one fossil locality that had every complete fossil of every horse species that ever lived in successive ages, he’d still find an excuse to reject it.   Constructing an evolutionary tree is like putting the pieces of a puzzle together when the pieces are located in different rooms of a house.  I wouldn’t call that circular reasoning.

In “Horse fossil defies evolution” Hastie demonstrates that he doesn’t really understand evolution.  He refers to an article from National Geographic Magazine about a fossil site in Nebraska.  He doesn’t even mention the name of the fossil site–an unscholarly omission–but I’m certain the article’s about the famous Ashfall fossil site.  Hastie thinks he’s disproven the evolution of the horse because extinct species of both one and three-toed horses were found at the site, showing they lived at the same time.  He thinks this is evidence that one-toed horses could not have evolved from three-toed horses.  To put it bluntly, his reasoning is just stupid.  Evolution doesn’t occur in a neat linear models.  Instead, it is more comparable to a bush upon which different branches can exist at the same time, although they all originated from the same trunk.  One species doesn’t necessarily evolve into another and then suddenly become extinct itself.  Speciation usually occurs in geographically isolated populations which can later colonize regions where their ancestors still live.  There are many extant species today that coexist with their ancestral species.  Fish crows (Corvus ossifragus) evolved from common crows (Corvus brachyrhyncos) and both coexist today, sometimes in the same habitat.

Bruce Macfadden’s chart of horse evolution.  Note it’s more like a bush than a linear line, as incorrectly depicted in old science textbooks.

In “What happened to the horse?” Hastie makes several false or unsubstantiated claims.  First, he states that a fossil of eohippus was found in the same sedimentary strata as that of a modern horse, and he rejects the scientific explanation that the older fossil was reworked by claiming there’s no evidence of geological activity that would cause reworking of an older fossil into younger strata.  I have no way of checking this claim because he doesn’t cite the scientific article he gleaned this bit of information from.  He also gives no scientific reason why he rejects the possibility of reworking.  He’s a Presbyterian minister, not a geologist, so he has no qualification or knowledge to make this kind of judgement.  Second, he claims horse evolution is contradicted by genetic evidence.  This is false.   The only genetic studies of horse evolution merely suggest the number of Pleistocene horse species is much fewer than previously thought from what scientists had gathered from fossil evidence.  Scientists already agree there was only one genus of horse in the Pleistocene.  I researched this topic and could find no genetic studies of Pliocene or Miocene horses.  Third, he states the lineage of horse evolution was debunked 40 years ago.  Again, this is false.  Scientists noted that the original model of horse evolution as depicted in textbooks was an incorrect oversimplification.  Scientists still accept the evolution of the horse beginning with the dawn horse and ending with the modern horse.  They simply corrected the original model which incorrectly showed a neat linear progression and included dead-end species no longer believed to be directly ancestral to modern horses.

This is the evolution of the horse toe bone.  There’s a reason why creationists attack this with such ferocity.  It’s good evidence of evolution.

Predators of Predators in the Insect World

September 12, 2011

Here’s a better photo of a blue-winged wasp (Scolia dubia) than the one I posted a few weeks ago when I was showing how they destroy my grapes.  This photo is from google images.

A few weeks ago I gingerly picked grapes from my vine because yellow jackets and blue-winged wasps were also enjoying the fruit.  It occurred to me that I knew nothing about the latter insect, so I mind-melded with google for some interesting facts about them.  Blue-winged wasps are a member of the mutillid family which also includes velvet ants and cicada-killers–predatory insects that sting and paralyze their victims, carry them to underground lairs, and lay their eggs on them.  The eggs transform to the larval stage and feed upon the helpless insect.  That’s all the protein they’ll ever need.  When they become adults they only require sugar for energy, explaining why the creepy creatures haunted my grape vines.   Blue-winged wasps specialize in preying upon green june bugs.  June bugs are a garden pest, so blue-winged wasps are beneficial insects.

Photo from google images of a cow-killer ant, a kind of velvet ant (Dasymutilla sp.).  They’re not actually ants but instead are wingless wasps.  They’re pretty common in my yard.

Cicada-killers (Sphecius sp.), as the name would suggest, specialize in preying upon cicadas.  But velvet ants, also known as cow-killers because their sting is painful enough to kill a cow (an exaggeration, of course) parasitize cicada-killers and bumble bees.  They show no mercy to their close relatives, nor to their distant bee cousins.  They are predators of predators.  I often see these wingless solitary wasps scurrying about bare soil areas in my yard, especially where the grass has been killed by the cars I park on the lawn.  (I purposely park on the lawn.  Less grass to cut.)  Bare soil was a common habitat during the Ice Ages.  Frequent drought and megafauna overgrazing, trampling, and digging created many spots devoid of vegetation.  Moreover, many species of wild grasses grow in clumps rather than forming carpetlike lawns.  The mutillids like bare soil because it’s easy for them to dig their chambers without having to go through a grass barrier.  Because favorable habitat was abundant during the Ice Ages, mutillids must have been as well.

I didn’t think I’d find a Pleistocene angle for this group of organisms.  Studies of Pleistocene insects are rare although there are some.  Insects are less likely to be preserved than fossil vertebrate bone or shelled molluscs.  I was surprised to find that there has been a study of Pleistocene mutillids.  Scientists determined that changing Pleistocene climate phases increased species diversification of nocturnal velvet ants in southwestern North America where at least 300 species live.  Speciation occurs more rapidly in the insect world because several generations of the short-lived creatures can live within the timespan of just a year, greatly speeding up the possiblity of evolution.  Scientists used an analysis of velvet ant DNA to make this determination.

Reference:

Pitts, VP;  JS Wilson, and CD von Dohlen

“Evolution of the nocturnal Nearctic Sphaeropthaliminae velvet ants (Hymenoptera: Mutillidae) driven by Neogen Orogeny and Pleistocene glaciations”

Molecular Phylogenetic Evolution 56 (1) July 2010

 

If I could Live in the Pleistocene (Part V)–Bringing back Marijuana (Cannabis sativa)

September 7, 2011

Photo from google images of a wild marijuana patch.  I had a friend from Iowa who told me that marijuana was a common weed in roadside ditches there.

For those unfamiliar with this blog I write an irregular series fantasizing about going back in time to live during the Pleistocene.  I would bring along some modern conveniences that I don’t want to live without.  I choose 36,000 BP, an interstadial, because I love virgin oak forests which prevailed then.  The climate was just perfect during the time period–much cooler summers but only slightly cooler winters with more snowfall than present day Georgia usually gets.  I’d live in a stone fortress to keep me safe from the beasts.  My little castle is located near the confluence of what today is the Broad and Savannah Rivers for easy access to such potential food as fish, waterfowl, turtles, and shellfish.  Stonewalls around my castle protect a garden and fruit orchard, and I’d also raise geese, chickens, milk cows, and honeybees, so my Pleistocene life is self-sufficient, though for emergencies there’s a time tunnel connecting me to 2011.  One of the plants I would bring back in time to grow in my garden would be marijuana (Cannabis sativa).

The modern world is full of outrageous absurdity.  Our so-called civilization allows coal companies to destroy beautiful mountains, transmogrifying them into permanent craters as barren as the moon.  This short-sighted destruction creates wealth for a few but leaves nothing behind for our descendents but useless wasteland.  Big slurries of black sludge, a biproduct of this kind of mining, buries once pristine freshwater creeks.   The smog from burning coal poisons those living near power plants, and the mercury deposits turn fish into toxic food, potentially causing brain damage to people consuming what would otherwise be a healthy dietary choice.  Although the majority of society opposes mountain top removal mining, it is legal because paper money changes hands between coal company criminals and crooked politicians.   Even in West Virginia, a solid majority of people oppose this kind of mining, but not a single state legislator does.  Our so-called civilized society accepts the legality of this barbaric devastation of the land, yet people growing a plant that makes users feel pleasant are sentenced to long prison terms.  Marijuana became illegal the same year prohibition ended.  I believe the real reason it became illegal was so the government could save the jobs of federal law enforcement agents with nothing to do when beer was allowed to flow legally again. 

Before and after picture of mountain top removal mining.  This travesty is legal but growing and smoking marijuana is illegal, proving there is no logic in law whatsoever.  A law is simply an excuse for people in power to subjugate people who are not in power.  Judges rule based on precedent.  Of course, if a judge disagrees with precedent, they rule differently based on their own reasoning.  In other words judges fabricate bullshit.  I wish I didn’t have to live in a world where mountain top removal mining is legal and marijuana is illegal.

In my Pleistocene world 36,000 years BP there are no illogical laws.  There’s no mountain top removal mining, and I can grow and smoke marijuana, if I want.  And I want.  I would have to bring marijuana seeds back in time with me.  It’s unlikely any kind of cannabis ever grew wild in Pleistocene North America because it’s not native to the continent.  Wild marijuana originally grew in central Asia and China, thriving in low moist but well drained areas, perhaps fertilized by elephant or water buffalo dung.  The oldest fossil remains of cannabis fiber comes from a 12,000 year old fishing site near the south China coast.  It belonged to either Cannabis sativa or Cannabis indica, the psychoactive kinds, or Cannabis ruderalis–industrial hemp.  Humans used the fiber to construct nets and fishing lines.  The 3 species of cannabis were among the first of cultivated plants.  6,000 years ago Chinese farmers grew marijuana with millet, wheat, rice, and beans.  Marijuana seeds are nutritious but bland.  It was primarily grown for the fiber.

Humans probably first found marijuana plants growing in their trash middens where the soil was fertile from accidental composting.  Cannabis is an annual weed that could easily colonize such habitat.  People looking for fibrous plants to weave clothes or nets to catch fish or birds utilized marijuana as a useful plant for such purposes.  The discovery that marijuana causes a pleasant high was a happy accident.  Thousands of years ago, there was no paper to start fires with.  Instead of paper, dried weeds were used.  On a cold windy day a family group huddled around a fire in a cramped tent or hut.  The smoke from burning the dried cannabis weed gave this ancient family a euphoric feeling.  Someone recognized the source of the euphoric feeling and spread the word.  One primitive genius decided more would be better and invented a pipe so he could inhale the smoke directly.  This forgotten individual ranks on par with Thomas Edison and the Wright brothers.

Later in human history, pot smokers learned how to cultivate marijuana to increase the tetrahydracannabinol (the active ingredient) content.  Pot farmers remove all the male plants which forces the females to grow bigger buds in a desperate attempt to capture scarce pollen.  The buds are where THC concentrates.  Cultivating seedless buds creates a higher quality marijuana known as sensimilla.

 

Photo of semsimilla bud from google images. If I could live during the Pleistocene, I’d be smoking this in my little castle while looking out the window for long-horned bison, giant ground sloths, and mammoths.

The Extinction of Critchfield’s Spruce (Picea critchfieldii)

September 3, 2011

Photo of a white spruce (Picea glauca) from google images.  The extinct Critchfield’s spruce was similar enough to this species that scientists originally misidentified it as such.  The size of the cones, cone scales, and needles differ to a statistically significant degree between the two.

Critchfield’s spruce dominated lower Mississippi River valley forests during the Last Glacial Maximum (~28,000 BP- ~15,000 BP) and commonly occurred throughout the southeast elsewhere.   That such a once abundant tree became completely extinct is surprising and a little unsettling.  It means that common and beneficial plant species that we take for granted today could abruptly become extinct in the future.  Since the 19th century Americans have already experienced the catastrophic loss of the American chestnut and are witnessing the perhaps irreversible decline of the hemlock–both due to human-introduced diseases and insects.  These species have existed for millions of years.  Our environment is becoming more and more impoverished.  However, man is probably not the culprit for the extinction of Critchfield’s spruce.

Fossils of Critchfield’s spruce have been excavated from the Tunica Hills region in Louisiana (as discussed last week) and Nonconnah, Tennessee.  In both of these locations it was found in association with mixed hardwoods such as oak, maple, walnut, etc.  In Georgia Critchfield’s spruce fossils were found at Bob Black Pond in Bartow County (northwestern part of the state) and Andersonville Clay Pit (southwestern part of the state).  At the former site Critchfield’s spruce fossils were found in association with fossils of northern species of trees–pitch pine, jack pine, red pine, white pine, and white spruce.  Evidentally, in the northern part of its range, Critchfield’s spruce overlapped with boreal species.  To the east and west of these fossil localities remains of Critchfield’s spruce are unknown, but its presence can be inferred from the pollen record.  Spruce pollen is present but not dominant in pollen studies from central and southeast Georgia, and South Carolina during the LGM.  And there is a 12,000 BP pollen record in north Florida of an unusual forest consisting of beech, hickory, and spruce. The spruce pollen undoubtedly originated from the  Critchfield’s spruce species.   Scientists assume that unlike its relatives it was a temperate species.  All the fossil wood from this species dates from 25,500 BP-16,000 BP, but spruce pollen continued to appear in southeastern pollen records until ~9,000 BP, indicating it survived until then.

This is a page from the below referenced paper that diagnosed Critchfield’s spruce as a distinct species. 

Southeastern pollen records show an inverse relationship between spruce and oak.  During interglacials and interstadials oak pollen increased while spruce pollen decreased.  During stadials pine and spruce pollen increased while oak pollen decreased.  Stadials were colder, drier, and windier, and had lower levels of CO2 in the atmosphere.  Conifers are better able to grow in these conditions.  Their springy limbs bend and sway in windstorms and icy weather; limbs from hardwoods more readily break.  Plants need CO2 for respiration.  The needles on conifers are more efficient at respiration than broad leaves, and they also lose less water during drought.  In warm wet climates with higher CO2 levels broadleafed trees tend to outcompete and shade out conifers.  This explains the cycle.

Data from ODP (Ocean Drilling Project) 1059A (see my May archives for an article about this), the only pollen record in the south from 150,000 BP-50,000BP,  shows that spruce pollen decreased rapidly following the end of the Illinois Ice Age and ranged between 0%-5% during the Sangamonian Interglacial and early Wisconsinian Ice Age.  It didn’t rise significanly again until 70,000 BP when it reached 10%.  Though Critchfield’s spruce must have declined to low numbers during the Sangamonian Interglacial, it didn’t become extinct as it did in the present one which brings to mind the question of why did it become extinct?

The authors of the below referenced study give 3 speculative causes for its extinction.  A pathogen spread as the climate warmed.  Critchfield’s spruce failed to disperse and colonize newly available habitat–something other species of spruce did as the Laurentide Glacier retreated.  And habitat space disappeared when broad-leafed trees outcompeted them.  I would like to add some other speculative causes.  It could have just as easily been an insect infestation as a pathogen in an environment with a longer time for a potential insect pest to reproduce.  Maybe it was a pathogen spread by an insect or a pathogen plus an insect infestation.  During previous interglacials broad-leafed trees very nearly outcompeted Critchfield’s spruce into extinction, but the latter survived in some refuge per chance.  Maybe this time perchance it didn’t find that refuge.  I doubt man played a role in its extinction, but there is a possibility Indian-set fires eliminated these isolated refuges where this tree had previously survived during interglacial periods.

Reference:

Jackson, Stephen; and Chengyu Weng

“”Late Quaternary Extinction of a tree species in eastern North America”

PNAS 96:24 11-23-1999

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This is a vegetation map of the southeast during the LGM that I’ve produced based on my complete study of available pollen records.  Like all vegetation maps, this is a vast oversimplification.  The solid black represents an environment dominated by the extinct Critchfield’s spruce.  This region also included mixed hardwoods, extensive meadows, and some wetlands.  Boreal species grew in the northern part of this region.  Crosshatching represents a pine dominant environment mixed with oaks, other hardwoods, Critchfield’s spruce, grasslands, wetlands, and even patches of desert-like habitat including scrub oak and eolian sand dunes.  The dotted region was likely bur oak and cedar savannah with some Critchfield’s spruce.  To the north below the Laurentide Glacier was a mixture of boreal spruce forests, grassy steppes, and bogs depending on local conditions.  The southern tip of Florida consisted of open pine savannahs and cypress swamps.  It was out of phase with the rest of the continent due to a shift in the Gulf Stream–south Florida had warm wet conditions while the rest of North America had cold arid climate.  Along the coast maritime oak, coastal prairie, and salt marsh prevailed.

Partial list of northern fauna that colonized the southeast during the LGM.

red squirrel

northern flying squirrel

porcupine

fisher

caribou

stag-moose

helmeted musk ox

pine siskin

gray jay

sawhet owl

snowy owl