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Tuesday, May 29, 2012

The Dating Game: Digging Up Fossils



Since ancient times, people had been digging up bones and other mineralized remains of creatures that lived and died a long, long time ago.
When dinosaur bones were unearthed in China about a thousand years ago, people wondered about the kinds of animals that had these bones. This was probably the start of dragon legends.

All over  the world, there are places that if one digs deep enough, one may find some ancient shells, bone fragments, a piece of petrified wood, or even a leaf print.
These relics are called fossils. They are usually found through digging. In fact, the term "fossil" comes from a Latin word that means, "to dig." Fossils are remains of ancient life; they give us clues about the distant past. Countless animals and plants that lived a long time ago were preserved in different ways. In hot and dry places, actual bones or teeth of an extinct creature are sometimes preserved; in moist places, the relic may be replaced by a rock-like copy of the original and thus fossilized. This process is called permineralization, and this takes place slowly over millions of years. This means that a fossil of a bone is no longer technically a bone; chemically, the fossil may be more like a rock. Also, if a once-living thing was a tree, the fossil may be a part of a tree trunk that underwent replacement of woody material with minerals. This is how the Petrified Forest came into being, which you might want to look up. 
Fossils range in age from 3.5 billion-year remains of algae to the 10,000-year-old actual remains of giant wooly mammoths preserved during the last ice age. Most fossils are excavated in sedimentary rock layers. Sedimentary rock is rock that has formed from sediment, like small pieces of rock, sand, or mud. These small pieces of debris are compressed and buried under more and more layers of sediment. After many, many years, they become sedimentary rock. Layers beneath are older than the layers near the surface. Paleontologists (scientists who study prehistoric life) use fossils to learn how life has changed and evolved throughout the planet's history.

 So, how do they know a fossil's age? Dating fossils is a relatively straightforward process. There are actually several methods. Here are some of them:
1.       Stratigraphy is the oldest method of fossil dating. This method involves the depth of a fossil's location. For example, dinosaur bones are usually found in sedimentary rocks; these rock layers are formed periodically over time. Newer layers are formed on top of older layers, compressing the older layers, turning them into rocks. Paleontologists can estimate the amount of time that has passed since the layer containing the fossil was formed.
2.       Scientists can also observe the fluctuations of the Earth's magnetic field. Rocks from different geological eras are affected by these magnetic field fluctuations, enabling scientists to study these, and provide an estimate of the rocks' age. This method is also called Paleomagnetic dating.
3.       Radioisotope dating of igneous rocks near the fossil can also be used. Unstable radioactive isotopes of elements, like Uranium-235, decay at constant rates. Examination of the remaining radioactive elements provides an accurate estimate of a rock's age. Radioisotope dating, however, is not used directly on fossils, since they do not contain radioisotopes used in the dating process. Instead, scientists date igneous layers of rock, found beneath and above the fossil (or fossils). These layers of rock are volcanic in origin; hence, some fossils, especially dinosaur fossils, are dated with respect to volcanic eruptions.
4.       There are fossils that are widely distributed in the planet but have a limited time span. These are the index fossils, and they are important in determining ancient biological history. Brachiopods (appeared during the Cambrian Period), trilobites (Pre-Cambrian, early Paleozoic, Paleozoic Period), ammonites (Triassic and Jurassic Period) are a few examples of these index fossils. The presence of index fossils helps scientists in making an educated estimate of other nearby fossils' age.

Excavating fossils is actually the tricky part. After locating the fossil, it must be carefully freed, without damaging it, from the rocky environment that served as its home for probably millions of years. First, the fossil (or fossils) should be labeled and photographed while still encased in rock. Its position should be noted carefully and meticulously. Using tools like picks and shovels, most of the overlying rock is removed. The rocks closest to the fossil, however, are removed with smaller hand tools like trowels, hammers, whisks, and dental tools. The exposed fossil is again labeled and photographed. Sometimes, not all of the overlying rock is removed at the dig site. The rest is carefully removed at the laboratory. Large fossils, in contrast to small fossils that are excavated with small hand tools, require more effort and bigger tools to expose-tools like shovels, picks, jackhammers, and even explosives.

Although excavated differently, both large and small fossils have to be treated very, very carefully to avoid damaging them. Fragile fossils, before removing them, are applied with a quick-setting glue using a brush or a sprayer. The fossils are packed very carefully before moving them to the laboratory. Large fossils are wrapped in paper or burlap, and applied with a layer of plaster (similar to those used in setting broken bones). Smaller ones can be packed in bags or boxes.
After being located, dug up, exposed, packed, and sent to the laboratory, it is now time to put the pieces together, much like piecing together a jigsaw puzzle. It is very rare for a whole skeleton—of any animal—to be found; sometimes, there are even pieces of different animals at the same site, which can add to the confusion. Knowledge of anatomy is therefore important to piece the fossils together, and to guess what the missing pieces are.
Paleontology is the science of fossils. The term comes from the Greek words logia (science), palaios (very old), and onta (existing things). Paleozoology is the science of extinct animals; the science of extinct plants is paleobotany.
Through the study of fossils, scientists have been able to put together a "picture" of what the world was like many ages ago. They have found evidence that the Himalayas, the Alps, the Rocky Mountains and other mountains were once under water.
How did the scientists know that? For one thing, they found fossils of sea animals high up on the slopes of these mountains. Obviously, these sea creatures did not climb up there. Scientists also found out through fossils that Europe and the United States were once covered with tropical forests; and that camels once roamed the plains of North America; that elephants and rhinoceros once lived in the Philippines.

Fossils also provided the clues that enabled scientists to trace the planet's animal life back to the earliest worms and shellfish, and that the great deposits of coal and chalk were the remains of living things that died millions of years ago. Of course, through fossils, we now know that giant reptiles (the dinosaurs) once roamed the earth; that these dragon-like monsters, at least some of them, stood more than a hundred feet long—the largest land animals that ever lived. We also know that when it comes to survivability, size doesn't matter—hundreds of giant species died out and made way for creatures with more brains and less bulk.
Fossils also tell us that modern humans have existed on this planet for "only" about half a million years. Compare that to the cockroach, which has been on this planet for hundreds of millions of years. Being the planet's Johnny-come-lately, it is no coincidence that among the latest fossils are those of early humans, which are found mostly in the Great Rift Valley, East Africa.
Humans were indeed "created" last.

Friday, May 18, 2012

Under One God: The Legacy of Monotheism

Simply put, monotheism is the belief in the existence of a single god, in contrast to polytheism, which is a belief in the existence of many gods.
Until the advent of monotheism, polytheism was the norm among the early civilizations. Civilizations that worshiped many gods were traditionally more accepting and more tolerant of the gods of other people, e.g., the Sumerians, Hittites, etc. (Hittite state documents unearthed by archaeologists often bear the invocation “The Thousand Gods of the Hatti.”) 

The first monotheistic religion may have been the worship of the Sun God Aten in ancient Egypt, which was established by Amenhotep IV (1364-1347 BC).
Aten

However, this did not last, as a subsequent pharaoh eradicated the worship of Aten. Then sometime before the 6th century in Persia, Zoroaster (or Zarathustra) founded Zoroastrianism, which many  scholars believe to have influenced the three major religions—Judaism, Christianity, and Islam.  
Zoroastrianism recognizes one god—Ahura Mazda—as the creator of all things.
One of the symbols of Zoroastrianism
Of course, religious conservatives do not acknowledge the connection between Zoroastrianism and their religion. On the other hand, most religious historians believe that the major religions have their roots in Zoroastrianism. 

Other similarities between Christianity and Zoroastrianism include:
  • Holy Spirit
    Ahura Mazda has a Holy Spirit that sometimes seems to be him and at other times seems to be independent. The Holy Spirit of Christianity has the same characteristics.
  • Saviour
    Christianity has Jesus who was born of a virgin and will return at the end of time to defeat evil and establish his kingdom; Zoroastrianism says that the Saoshyant or saviour will be born of a virgin and will lead humanity in the last battle against evil.
  • The devil
    The Christian Satan parallels the Zoroastrian Ahriman or Angra Mainyu.
  • Angels
  • Archangels
    Christianity has seven archangels; Zoroastrianism has seven Amesha Spenta.
  • Immortality of soul and life after death.
  • Heaven as a place of reward for the righteous, and hell as a place of punishment
  • Resurrection at the end of the world, when the dead revive and the new world will have a fresh life and new beginning.
  • The last judgment

The “us against them” mentality fits beautifully into monotheism’s basic tenet.
It has this deadly formula: since there is only one god, the god (or gods) that other people worship must be false; hence, these other people are unbelievers.
And we all know how the major religions, particularly Christianity and Islam, treated the “unbelievers.” 
Consequently, monotheistic religions are less tolerant, less accepting, of other people’s beliefs.
Accepting the existence of other gods will mean a negation of their own. So for their religion to survive and spread, they have to deny other people’s gods. In so doing, a whole lot of mess is opened—genocide, hatred, intolerance, bigotry, wars, and still more wars.
Religious and political leaders may state that the world may be united under one God, but which God? The divisiveness ingrained in religion will never go away; uniting the world can only result in bloodbath.  
Nothing separates humanity from one another as thoroughly, as completely, as religion.

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