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Mollusca


Throughout the history of man there have been many creatures that have been over exaggerated, feared, and misunderstood. The creatures known as mollusks are no exception. Long ago sailors would tell stories of kraken destroying entire ships. But these creatures are far from “out to get us”, they are actually vitally important in many aspects of human life today.

The immense numbers and diversity throughout the Phyla Mollusca truly lend hand to just how very important they are to the ecosystems they live in, and how much we as humans rely on them for many things. They feed so many creatures including us, they decorate us and help us tell age old stories, and they help us to have a fighting chance at keeping many different habitats as preserved as possible. The beauty and intelligence’s has amazed so many people for many years, and that amazement does not seem like it will be letting up any time soon. It seems that the ancient myths of creatures like the kraken might not be as far off as we thought, just take a good look at a giant squid.



Bibliography

Bunje, Paul. "The Mollusca." University of California Museum of Paleontology. University of California Museum of Paleontology, 2003. Web. 24 Jul 2010. .

Martin, Scott. "Terrestrial Snails and Slugs (Mollusca: Gastropoda) of Maine ." Norteastern Naturalist 7.1 (2000): 33-34. Web. 24 Jul 2010. .

"The History of Jewellery: Origins of Jewellery Design." All About Gemstones. All About Gemstones, 2010. Web. 24 Jul 2010. .

Kazlev, Alan. "Phylum Mollusca." Palaeos. Palaeos, 28 Dec. 2002. Web. 24 Jul 2010. .

Kowalewski, Guillermo. "Clams Hold Story of Ailing Colorado River Delta." Lycos Network (2000): n. pag. Web. 24 Jul 2010. .

References

The History of Jewellery: Origins of Jewellery Design

"The History of Jewellery: Origins of Jewellery Design." All About Gemstones. All About Gemstones, 2010. Web. 24 Jul 2010. .


Jewelry From The Dawn of Man


Jewelry in its most basic form has been used since the dawn of of man, in conjunction with the earliest-know use of both clothing, and tools. Evidence of the first humans dates back some 6 to 7 million years, based on a recently discovered skull that was found in the Central African country of Chad. These first humans were nicknamed the "Toumaï," but very little is known of their lives.

Before written language, or the spoken word, there was jewelry. In the late 1800s, British archaeologist Archibald Campbell Carlyle said of primitive man "the first spiritual want of a barbarous man is decoration" [2]. More than just a curio from the past, jewelry, like art, is a window into the soul of humanity, and a poignant reminder of that which separates humankind from the animal kingdom — a desire to capture the essence of beauty, to posses its secrets, and to unlock its mysteries.

Recently discovered mollusk or nassarius kraussianus shells that had been perforated to be strung into beads (photo above, left) are now thought to be some of the oldest known man-made jewelry. This mollusk jewelry was discovered in a cave in Blombos, South Africa, and dates back to the Middle Stone Age, some 75,000 to 100,000 years ago.
Clams Hold Story of Ailing Colorado River Delta

Kowalewski, Guillermo. "Clams Hold Story of Ailing Colorado River Delta." Lycos Network (2000): n. pag. Web. 24 Jul 2010. .

BLACKSBURG, Virginia, December 1, 2000 (ENS) - The biological productivity of the Colorado River Delta is just five percent of what it was before the river's water was diverted for human uses. Researchers from the U.S. and Mexico used shellfish to examine the delta's health, pioneering a technique that could be used in other waterways around the world.

Since the 1930s, an environment that supported billions of clams and other life has disappeared because dams and irrigation projects have reduced the flow of nutrient laden fresh water to the tidal flats of the Colorado Delta.

A new approach for measuring life on the delta over the last thousand years, introduced in a study by researchers from four universities, could also be used to estimate the prehistoric productivity of coastal ecosystems in other parts of the world. Such estimates will be especially valuable in areas where no biological surveys were made before humans modified the habitat.

Seen from the ground, the shells form miles of sun bleached ridges, originally shaped by spring floods, tides and the passing of generations of abundant shellfish. In the last seven decades, since the river's flow virtually stopped, the clams have become sparse.

By dating 125 shells collected from throughout the inter-tidal zone, the researchers learned that essentially all specimens came from the last 1000 years. Every 50 year time period between 950 AD and 1950 was represented among dated specimens, showing that shells were continuously produced in the delta before humans altered the river.

The two trillion clam shells washed up onto the delta tidal flats represent 1,000 years of biological productivity. Because shells grow as the animal secrets new layers of material, the scientists could measure life span of long dead clams by counting the seasonal oxygen isotope cycles in the shell. In the spring, water from snow melt has fewer isotopes.

They learned that the average clam lived three years. So in 1,000 years, there were 333 generations of clams. That means that at any given time there were six billion clams living on the delta, with an estimated density of 50 clams per square meter.

The researchers found that where, according to their estimates, there were 50 specimens per square meter in the past (about five per square foot), today there are only three per square meter (about 0.3 per square foot).



"These estimates indicate a 20 fold drop in the shellfish productivity in the delta since the river has been diverted by humans," says Kowalewski.


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