Archive for August, 2018

The Pinhotti Trail in North Georgia and Alabama

August 28, 2018

The Pinhotti Trail connects with the more famous Appalachian Trail and is 335 miles long.  I hiked the first half mile from the Georgia side a few days ago.  This section of the trail goes up a rocky steep mountain side, and the forest is dominated by mountain chestnut oak, hickory, and Virginia pine with an undergrowth of maple saplings, dogwood, and muscadine grape vines.  I also saw silver maple, red maple, black oak, and overcup oak.  It is excellent habitat for chipmunks, though I didn’t see any.  Chipmunks like to tunnel in the crevices under boulders, and the oak and hickory trees provide plenty of acorns and nuts for them.  Perhaps I didn’t see any chipmunks because they were hiding from a weasel or skunk.  The distinct odor of a mustelid was present near the entrance of an hollow log.  Weasels kill prey in bunches–far more than they usually consume–so maybe the local chipmunks had been recently decimated.  A camera trap could probably produce video of a weasel going in and out of the hollow log.  I didn’t see any birds, but I was only on the trail for about 25 minutes.  I did hear a chickadee and the partial call of a woodpecker, and this time of year there is the ever present mating sound of cicadas.

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Map of Pinhotti Trail.

The forest here is dominated by mountain chestnut oak, hickory, and Virginia pine.

Mountain chestnut oak leaves.

Can anyone identify this species of mushroom?  I can’t find it in my field guide or on the internet.

Chipmunks like to tunnel in crevices under boulders like this.  This part of the trail is excellent habitat for chipmunks.

Boulder field.

I could smell the odor of a skunk or weasel near the entrance of this hollow log.

 

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Gulf Fritillary and Passion Flower Vine

August 21, 2018

Butterfly migration is even more amazing than bird migration.  Bird migration includes the same generation, but butterflies that begin migrating north never live long enough to return south.  Instead, butterflies gradually expand their range north as the weather warms; breeding, laying eggs, and dying.  The next generation advances farther north.  Then, several generations later, they begin moving south, retreating before killing frosts.  The gulf fritillary (Augraulis valinae) is an example of a migratory butterfly.  They winter in Florida, south Texas, and Mexico, but generations of them migrate as far north as Pennsylvania.  Gulf fritillaries were named because they are some times seen fluttering over the Gulf of Mexico.  Their larva feed upon passion flower vine (Passiflora incarnata) foliage.  The adults obtain their energy from nectar in flowers , and as the below photo represents, they often find some nutrition in animal feces.  Gulf fritillaries are particularly fond of lantana, a non-native shrub that rapidly colonized Florida during early Spanish occupation.

Gulf fritillary snacking on dog feces.

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Passion flower.  Spanish conquistadors thought it symbolized the passion of Christ.

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The fruit of passion flower is edible.  The seeds are covered in a gelatinous substance with a sweet-sour flavor and a tropical aroma.  Brazil produces and consumes the most passion fruit.  Imported passion fruit is occasionally available in the grocery store.

There are between 520-700 species of passion flower vine–taxonomists disagree about the number of species.  96% of them occur in the Americas, indicating this is where they originated.  Other species live in southeast Asia, Australia, and Pacific islands.  They probably colonized these regions by rafting on clumps of debris ripped from the land by  tropical storms.  P. incarnata and the crinkled passion flower (P. gracilis) are the only species that evolved to live in temperate climates.  P. gracilis  is restricted to 1 county in South Carolina, while P. incarnata ranges throughout eastern North America.  During the Miocene when most of North America was sub-tropical there were probably many species of passion flower native to North America, but just 2 evolved the ability to survive frosty seasons.

Passion flower vines are shade intolerant but drought tolerant.  They prefer disturbed areas, and I’ve found them growing on vacant lots in my neighborhood.  This species was well adapted to live during the Pleistocene when rapid climate change and megafauna foraging often drastically altered local landscapes.  Mammoths and other large animals girdled and uprooted trees, opening up the canopy so shade intolerant passion flower vines could thrive.  Many vertebrates, perhaps peccaries, fed on the fruit and distributed the still viable seeds in their dung.  Long Ice Age droughts also killed trees and let passion flower vine spread in the available sunshine, climbing over grass and tree saplings and across bare sandy soils.

When the Spanish conquistadors conquered the Americas, they found passion flower vine growing everywhere.  The soldiers were super religious, though they ignored 1 of the 10 commandments when they were butchering the Indians.  They thought passion flowers symbolized the crucifixion of Christ, known as the passion by religious zealots.  Supposedly, the 5 petals and 5 sepals represent the 10 apostles.  The 72 filaments = the number of thorns in Jesus’s crown.  The 3 stigmas = the cross.  The 3 stamens = the wounds in Jesus’s hands.  The leaf lobes resemble the spear wounds.  The dark spots under the leaves represent the 33 pieces of silver given to Judas to betray Jesus.  The flowers die after just 1 day, just like Jesus died after a day on the cross.  And the petals reclose like the tomb enclosed Jesus.  Some superstitious priest sure had an overactive imagination.

Does a Clam Know it’s Alive?

August 15, 2018

The late Carl Sagan guessed there might be 1 million civilizations in our galaxy, the Milky Way.  He based this guess on the Drake Equation–a formula that takes the number of stars in the galaxy and multiplies it by fractions of: sun-like stars, sun-like stars with planets, planets in inhabitable zones, planets where life evolved, planets with intelligent beings, and the percentage in the lifetime of a planet with a civilization.  However, the Rare Earth Hypothesis proposed by Peter Ward and Don Lee in 2000 posits microbial life may be widespread in the universe, but complex life must be extremely rare.  Since the Rare Earth Hypothesis was proposed, astronomers have discovered 3600 exoplanets in solar systems outside our own.  The evidence so far indicates the Rare Earth Hypothesis might be the more accurate guess.  Of the 3600 exoplanets discovered just 1 is a rocky earth-like planet that orbits in an inhabitable zone.  It is known as Proxima b. All other planets found in habitable zones are gas giants with no surface, similar to Jupiter and Saturn.  Though Proxima b is located in an habitable zone, it probably does not support life because it is tidally locked, meaning 1 side of the planet always faces its sun.  Half of the planet is too hot, and the other half is too cold.

Complex life evolved on earth thanks to numerous unique characteristics that apparently are extremely rare elsewhere in the galaxy and probably the universe.  Earth is just the right distance from the sun, and the sun is just the right kind of star.  Our sun is bigger than 95% of other stars.  The habitable zones of planets orbiting smaller stars would have to be much closer, but this would make the planets tidally locked like Proxima b or Mercury.  Moreover, most other solar systems are binary.  Solar systems with 2 or more suns force planets to have wild perturbations in their orbits, causing a great frequency of cosmic impacts that extinguish complex life.  Earth is the only known planet with abundant tectonic activity which helps control CO2 buildup.  Without tectonic activity CO2 concentrations in the atmosphere amplify heat and scorch complex life into extinction.  Venus is an example of this kind of uninhabitable world.  And earth is lucky to have a large moon that stabilizes earth’s tilt.  The earth’s tilt varies between 23.5-25 degrees, but planets without a large moon may vary in their tilt by up to 90 degrees.  The resulting climate instability would cause the complete extinction of complex life.

Microbial life first evolved on earth about 4 billion years ago, but complex plants and animals don’t appear in the fossil record until about 700 million years ago–a colossal gap in time.  Most earth-like planets in the universe probably resemble the early earth of 2.5 billion years ago.  The earth of that time was mostly ocean with a few volcanic islands.  The ocean was brown from cosmic-impacted debris, and the sky was red in an atmosphere of little free oxygen.  Eventually, plate tectonics formed continents, and shallow water environments supported greater populations of photo-synthesizing bacteria that produced enough oxygen to support complex life.

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Illustration of early earth’s atmosphere.  Land was restricted to a few volcanic islands and the sky was red in an atmosphere with little free oxygen.

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Early microbial life on earth resembled these primitive thermophilic Archaea.  They can survive in temperatures exceeding the boiling point.  This suggests microbial life may be widespread in the galaxy, though complex life is much more rare.  It took over 3 billion years for microbial life to evolve into complex life on earth.

Though complex life must be rare, there are between 1-2 billion galaxies in the universe, each with up to 1 billion stars that in turn have close to 10 planets in their systems.  The universe is so vast complex life likely evolved elsewhere besides earth.  But why?

I think the universe would not exist without complex life aware of its existence.  Suppose complex life never evolved anywhere.  Sure, there could be billions of galaxies, but if there was nothing aware of all that matter, it might as well not exist.  No sentient being would know it was there, so it would not be there.  This is why I think the universe produces worlds where complex life evolved.  It is an attempt by the universe to exist.  It becomes self aware through the minds of many individual sentient beings.  This complex life can’t be just a tree or a clam or a thermophilic micro-organism.  I doubt those living things are aware of their own existence let alone the existence of the universe.  Dogs and cats are aware of their existence, but I doubt they contemplate the existence of the universe.  Give them a smelly piece of meat and a caress and that’s as far as their in depth thought of the universe goes.  I believe the universe strives to produce life that recognizes it exists.  Otherwise, it will cease to exist or it may as well not exist because no sentient being would know of its existence.  Without complex life equivalent or above the intelligence of humans, the universe would have no knowledge of its existence, so it would not exist.

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I doubt a clam knows it is alive.  I believe the universe depends on life more complex than this for its existence.  The existence of complex life and the universe is an interdependent relationship.

Reference:

Ward, Peter; and Donald Brownlee

Rare Earth: Why Complex Life is Uncommon in the Universe

Copernicus 2000

 

Pleistocene Bread

August 9, 2018

It is the 20th anniversary of my sourdough starter.  With my sourdough culture I make great bread, pancakes, and dumplings; and it can also serve as an excellent coating for fried fish and shrimp.  Wild yeast living in the atmosphere of Augusta, Georgia helps my bread rise without the need for store-bought yeast during summer months.  (The wild yeast needs some help when the house is cold.)  The discovery of bread must have been an happy and tasty accident.  Hunter-gatherers collected the seeds of wheat and other grains, but to make them more palatable, they removed the chaff, pounded the grains with rocks, and cooked them in water.  Crushed grains left over night or for a few days fermented.  This gruel could be consumed as a primitive beer or baked into bread.  Archaeologists debate over whether beer was a byproduct of bread-making or vice-versa.  Most think the effort to gather individual grass seeds was so tedious when many other plant and animal foods were available that only the desire for alcohol would’ve inspired primitive people to labor so intensely.  It should be noted this primitive beer did not taste like modern beer.  It was sour.  Bitter hops weren’t added to beer until the year 736 AD in Germany.

I started my sour dough culture in 1998 by exposing flour and water to air.

My sourdough bread fresh from the oven.

Archaeologists believe humans didn’t deliberately plant wheat until 10,000 years ago.  Yet, burnt bread crumbs, resembling toaster detritus, were recently discovered at a site dated to 14,400 years ago in Jordan.  The Natufians, hunter-gatherers roaming through the Middle East then, lived in sunken houses with stone floors and fireplaces, and apparently, they made bread.  Today, this region is a desert, but during the late Pleistocene it was an open woodland with many species of edible grasses growing between widely spaced trees.  The people often feasted on gazelle, wild sheep, and hare; and they ate bread too.  The bread was made with a mixture of primitive wheat, rye, millet, barley, possibly oat, and papyrus root.  The latter ingredient likely added necessary sugar to help fuel the yeast.  Modern bakers always add a little sugar or honey to their bread dough.  Archaeologists sifting though the site found 65,000 plant specimens including 95 species, but papyrus was by far the most common making up 50,000 of the specimens.  They also found mustard seed, peas, and of course the wheat, barley, rye, millet, and oats.  Mustard greens are edible, and the seeds were probably used as a condiment.  So some people were already eating bread during the Pleistocene.

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Artist’s representation of Natufian houses in Jordan 14,000 years ago.  The foundations are still visible.  They made bread in these houses.  The landscape was not as barren then as depicted in the illustration.

Reference:

Otaegui, P.; et. al.

“Archaeobotanical Evidence Reveals the Origin of Bread 14,400 Years Ago in North-Eastern Jordan”

PNAS July 2018

See also: https://markgelbart.wordpress.com/2012/08/05/humans-cultivated-figs-during-the-pleistocene/

Were Southeastern Wolves Feral Indian Dogs?

August 2, 2018

Archaeologists uncovered 10,000 year old dog (Canis familiaris) skeletons at 2 sites in Illinois.  The sites are known as Koster and Stillwell.  This is the earliest known evidence of domesticated dogs in North America, though scientists believe dogs traveled over the Bering Land Bridge with humans as long as 15,000 years ago about the same time they were first tamed.  Late Pleistocene evidence of dogs in America has either faded away or has yet to be found, but they were probably here.  The specimens from Illinois date to the Pleistocene/Holocene boundary.  The Stillwell dog was about the size of an English setter, and these early Indian dogs anatomically resemble coyote/dog hybrids (known as coydogs).  I hypothesize the wolves that lived in southeastern North America until about 1917 may have been Indian dogs that simply reverted to a wild state.

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Audubon’s painting of an Indian dog.  Indian dogs were so wolfish that European colonists often mistook them for wolves.

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Illustration of black wolf pack by Kelly Quinn.

Scientists classified the wolves that lived in southeastern North America until Europeans wiped them out as the red wolf (Canis rufus), but nobody really knows what they were.  A DNA test of a few specimens from Arkansas found they were hybrids of coyote (Canis latrans) x timber wolf (C. lupus), and wolves currently living in eastern Canada also appear to be coyote/timber wolf hybrids.  However, this still doesn’t explain what the now extinct wolves that lived in Georgia, South Carolina, and Florida were.  The so-called red wolf is not well represented in the fossil record, and the few specimens identified as red wolves may actually be coyotes.  They don’t appear in the fossil record until after dire wolves became extinct, and I think dogs brought by humans went wild and occupied the vacant niche created when dire wolves became extinct.  Although southeastern wolves varied in coat color, many were melanistic.  The gene for a black coat color in wolves originated in domesticated dogs and that was passed to the wolf population in the rare instances when wolves mated with dogs.  So I believe the wolves that lived in southeastern North America were feral Indian dogs with perhaps some admixture of timber wolf and/or coyote.  They were a primitive dog that like the dingo and Carolina dog readily reverted to the wild, especially those left behind when Indian tribes moved away from an area or died out.  Audubon almost mistakenly shot some Indian dogs because he reported that they looked just like wolves.  This resemblance may have contributed to their extinction, though diseases brought by the European colonists’ dogs were probably a bigger factor.  Europeans often mistook Indian dogs for wolves and killed them or deliberately exterminated them to prevent them from breeding with their well bred dogs..  A DNA study of the Koster specimen determined modern dogs have none of the earlier Indian dog ancestry, suggesting the ancient Indian dogs are extinct.

The Carolina dog descends from a later lineage of dogs brought by Eskimos about 1000 years ago.  Strange as it may seem, these dogs quickly evolved from long-furred Eskimo dogs well adapted to cold climates to the short-haired “Old Yeller” type dogs at home in the hot humid south.  Like the earlier Indian dogs, Carolina dogs also easily revert to a wild state.

The original Indian dogs may be extinct, but they did leave a modern day legacy. The only genetic imprint they left in modern dogs is a sexually transmitted cancer.  Geneticists found this cancer originated in the ancient Indian dogs and was passed on to modern dog breeds.

Reference:

https://www.sciencenews.org/article/dogs-lived-and-died-humans-10000-years-ago-americas