Astrology: Virgo (1 of 3)

Writing about my own Sign of the Zodiac has been difficult for me.  I know five people who are Virgos, and each of them is quite different from one another.  I had trouble in understanding how all of us could be Virgos.  Also, I was afraid that I will start to believe all that is written about Virgos will be entirely true for me.  However after researching this Sign, I was surprised at the wide range of characteristics that this Sign encompassed.  I was relieved to discover that there was enough latitude to include me and my friends.

The time of year that Virgo covers is from August 23 to September 23.  This is the clove time between summer (which is ending) and fall (which is beginning).  The Sign Virgo depicts a woman with a sheaf of wheat.  This image speaks of careful husbandry which ends in a bountiful harvest. The time of Virgo is the start of the harvest season.  

Virgo is the last of the six Signs of the Zodiac associated with individual development.  As an Earth Sign, Virgo examines what works and what does not in social relations.  Under Virgo’s direction, an individual learns what constitutes a healthy relationship.  Now a whole person, they can enter any relationship as an equal.

The trees that correspond to this Sign are nut trees.  These trees require time and attention to bring forth fruit.  They symbolize Virgo’s relationship as individual with the whole.  Like the Virgin, nut trees are nourishing and self-contained.  Like nut trees, Virgo is whole and complete.  

In Astrology, Virgo is an Earth Sign.  This means that Virgos are grounded and practical.  People of this Sign prefer order and structure.  As an Earth Sign, Virgo is also considered to be a Negative Sign as well.  This means that Virgos are more introverted and sensitive than the Fire Signs such as Aries.

Also in Astrology, Virgo is a mutable Sign.  This means that she is flexible in her interactions.  But, Virgo’s earth element helps to keep her grounded in her focus.  Virgo does desire order and structure in her life but is adaptable in how to achieve this.  However, people of this Sign are more willing to change than are people of Taurus, a fixed Earth Sign.

The planet Mercury governs Virgo, thereby enabling her to weave facts into a whole picture.  Moreover, she uses the creative urges of Mercury to form a work of art.  A typical Virgo trait is to separate the wheat from the chaff, and bake it into a whole loaf of truth.  Under Mercury’s influence, Virgo employs a strong sense of logic.  In addition, Mercury enhances Virgo’s analyzing skills with concise thinking.  Because of Mercury’s quickness, Virgo’s earthiness comes out as commonsense.  

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Dinosaurs: What Killed Them?

How and why dinosaurs went extinct has been debated for a long time.  Most paleontologists have settled on the asteroid impact theory.  Because of the huge disruption that this space object made, the earth’s climate changed.  Massive forest fires and dust clouds cooled the planet, causing everything larger than a crocodile to die off.  Moreover the asteroid left a layer of iridium, a rare element from space, which covered the extinction boundary.

However, there are a few who claim that the dinosaurs were under stress already.  The asteroid only hastened the demise of this weakened group of animals.  Fossil records show that fewer types of dinosaurs were living at the time of the asteroid’s impact.  Furthermore, the ecological niches formed by the new flowering plants were not being exploited by dinosaurs.

Moreover, one group of paleontologists analyzed a general pattern of dinosaur evolution.  As a rule, dinosaurs did not diversity to fill various specialized niches.  What brought these animals to prominence was the Triassic-Jurassic Extinction Event.  Dinosaurs took the role of disaster taxa and proliferated, crowding out other taxa.

Another theory that scientists often present is extensive volcanic activity.  As India separated from Madagascar, volcanoes in India became extremely active.  Forming the massive Deccan Traps in India, these volcanoes spewed forth dust and sulfuric ash that poisoned the air and water.  This could have placed extreme stress on the dinosaurs by destroying their environment.

Another reason for the demise of the dinosaurs could be disease.  According to this theory, insects rapidly expanded to fill the niche presented by the new flowering plants.  Many of these insects carry diseases that were fatal to some dinosaurs.  Therefore diseases further weakened the dinosaurs.

The problem with many of these theories is that they fail to explain the demise of the marine and flying reptiles that occurred at the same time.  Also frogs and salamanders, known to be sensitive to toxic changes, managed to survive to the present day.  In addition, these theories seem to focus on the larger dinosaurs, and neglect what may have happened to the smaller ones.  Some of the smaller ones may have evolved into birds, which exist today.

The evidence in the fossil record is that the climate became colder, and the sea level dropped.  Ice caps formed in Antarctica. What caused this dramatic change seems to be the impact of the asteroid.  This asteroid strike raised enough dust and ash to bring about such a sudden change.  The result was the extinction of so many different kinds of animals.

Works Used:

Haines, Tim and Paul Chambers, “The Complete Guide to Prehistoric Life”, Firefly: Ontario, 2006.

Little, Richard, “Dinosaurs, Dunes, and Drifting Continents: the Geohistory of the Connecticut Valley”, self-published, Hartford, CT, 1986.

Scott, Michon, “Strange Science: The Rocky Road to Modern Paleontology and Biology”, 2011, http://www.strangescience.net/,

Strauss, Bob, “Dinosaurs at About.com”, About.com, 2011, http://dinosaurs.about.com/,

Various, “Prehistoric Life”, Dorling Kindersley: New York, 2009.

----, “What Killed the Dinosaurs”, PBS.org, 2001, http://www.pbs.org/wgbh/evolution/extinction/dinosaurs/index.html,

Dinosaurs: Building Errors

The first recognized bones of dinosaurs were so large that naturalists named these animals “terrible lizards”.  As they tried to reconstruct these fossils, the naturalists had referred to animals that they already knew about.  Hence the result of their efforts was the idea that dinosaurs were large cumbersome beasts, which resembled lizards.

Other early ideas that naturalists had about dinosaurs were that they lolled about, and conducted belching contests.  And if dinosaurs had to stand up, they leaned on nearby trees.  Although there were no tailprints found with footprints in the fossil record, dinosaurs were depicted with their tails dragging on the ground.  This particular concept continued well into the 20^th Century.

Various early ideas of how dinosaurs looked are on display at the Dinosaur Court of the Crystal Palace in London.  Opened in 1854, the Court featured dinosaurs that looked like lizards or stood like mammals.  However by 1900, these depictions of dinosaurs were considered to be out of date.

The first dinosaur ever named, Megalosaurus was actually a theropod.  However, this animal was depicted in the Dinosaur Court as a gigantic four-footed monitor lizard.  Meanwhile, other early depictions gave these theropods elephant-like qualities as well as lizard ones.

Theropods, in general, were thought of as large mammals standing on sturdy legs, dragging their tails.  After two discoveries in 1858 and 1859, the view of theropods changed.  First the Hadrosaurus (an ornithopod dinosaur) was discovered in New Jersey.  This dinosaur walked upright.  Meanwhile one of the tiniest dinosaurs, the Compsognathus, was found in Germany.  Now evidence pointed to the fact that theropods could be any size and also walk upright.  However the notions that they were quick predators remained years off.

Meanwhile because of their large size, sauropods were believed to live in water or at the very least in swamps and marshes.  This idea came from the large whales of the oceans.  For example, Brachiosaurus was thought to stick its head out of water, while remaining submerged.  However, this massive dinosaur would have suffocated from the water pressure.  In addition, when the sauropods did walk on land, they were depicted as alligators with drooping stomachs and dragging tails.  The idea that these massive animals could use their tails as weapons had not occurred to naturalists at that time.

Dinosaurs: Warm or Cold-blooded?

Aptosaurus

In the 1800s, many naturalists saw the large dinosaur fossils as similar to modern lizards.  Since these early paleontologists did not know what these animals looked like, they made the dinosaurs resemble animals that they did know such as lizards or mammals.  The fossils that they found had neither hair nor feathers, therefore the naturalists believed that dinosaurs were sluggish.  Moreover, the large size of many fossils also led naturalists to think of dinosaurs as cumbersome and slow.  Therefore, people for a long time held the image of a large reptile for a dinosaur.  Dinosaurs were the giants of the earth who had to make way for the more nimble humans.

However, since the 1960s, paleontologists have changed their ideas about dinosaurs.  As more fossils with feathers were found, more scientists pondered the dinosaur-bird connection.  Some of the therapod dinosaurs seemed to have evolved into birds.  Since birds are warm-blooded, these particular dinosaurs must be warm-blooded too.

Later, fossils of dinosaurs were discovered at the Poles.  This cast further doubt on the cold-blooded theory, as well.  Modern reptiles cannot tolerate long periods of continual darkness.  Meanwhile, other fossil finds of groups and tracks of dinosaurs indicated that some dinosaurs lived in herds.  This meant that they lived in complex social structures, like warm-blooded mammals.  No cold-blooded animals today live in herds.

One problem in determining whether dinosaurs were warm-blooded is their large size.  An Apatosaurus would be too large to be warm-blooded, and would probably die from heat exhaustion.  Also such a large dinosaur would be a gigantotherm, achieving a constant temperature by virtue of its large size.

Also there is no conclusive physical evidence for either warm or cold-bloodedness amongst dinosaurs.  These animals share some characteristics of both reptiles and birds.  In addition, some mammals have traits of reptiles.  For example, the echidna of Australia lays eggs, and stands like a reptile, while the tree sloth of South America requires basking to raise its temperature.  Therefore whether dinosaurs were warm or cold-blooded still remains unknown.

What some paleontologists conclude is that dinosaurs could have evolved from cold-blooded species into warm-blooded species. Or dinosaurs could have been a transitional species between warm and cold-bloodedness in animals.  The fossil record is incomplete in offering definite proof of any one theory.  However for one group of therapods, which evolved into birds, these dinosaurs were probably warm-blooded.

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Ecothermic

Animals that are ectothermic obtain most of their body heat from their environment.  These animals cannot derive internal heat from their own metabolisms.  To maintain a constant body temperature, ectotherms take full advantage of the heat outside of themselves.  Since they are less dependent on their own metabolism to make heat, ectotherms only need a small amount of food to survive.  Therefore, they can exploit environments where food is scarce such as deserts.  Examples of ectotherms are the box turtle, marine iguana, naked mole rat, and tuatara.

Endothermic

Animals that are endothermic obtain their body heat from their own internal processes.  Because they need to fuel this cellular process, endotherms have to eat constantly.  For example, since they have high metabolisms, shrews and hummingbirds require frequent feedings.  To conserve their body heat, endotherms are insulated by fat, fur, or feathers.  Most mammals and birds are endothermic.  Robins, blue jays, squirrels are but a few of examples of endotherms.

Gigantothermic

Animals such as leatherback sea turtles and saltwater crocodiles are so huge that they exchange little heat with their surroundings.  These animals are known as gigantotherms.  Because of their large size, gigantotherms, such as the great white shark, have a low heat exchange of surface area to volume ratio.  This rate of exchange is small compared to the animal’s total size.