Analysis: The Paleodictyon Nodosum

Biologists, suited in wetsuits and snorkels, gently lift a large rock underwater before poking a dive light into the crevice. Two small eyes peek out at them, a wide grin and a flattened wrinkled body floating and bobbing with the current. The Eastern Hellbender, ancient giant salamanders that have roamed the Earth for millions of years, living dinosaurs that roam the bottom of non-polluted streams and shallow rivers preying on crawfish and earthworms.

Just last year, some researchers stated that the extinct aquatic animal, the ‘Tully Monster’ was a vertebrate, possibly a relative of today’s lampreys. Like a mismatched puzzle, the Tully monster lacks some vertebrate pieces and has others that are the wrong shape, researchers and colleagues report in the March issue of Palaeontology. (Palaeontology includes the study of fossils to determine organisms' evolution and interactions with each other and their environment, their paleoecology).

1. The author chose to focus on 375 million year old rock because the transition from fins to necks and limbs occurred then. The scientists knew that any time later than this and they would find lots of animals with limbs. But if they searched earlier than this time then there are only fish without necks. When the fish were evolving they evolved necks before they evolved limbs so this was a good sign in chronology. Sedimentary rocks are the best types of rocks for fossil due to their gradual pressure and low amounts of heat. Sedimentary rock is also found in lake beds and streams, where fish and aquatic wildlife are most likely to live.

Throughout this first chapter, I think that I already believe that I will enjoy this book. At the start however, the book could not be any more boring. Rocks, rocks, and more rocks was all I could think of. I have always been one to enjoy learning new things as long as they are interesting subjects, but learning about older and younger rocks, how rocks move throughout time, and what can be discovered from those rocks, that doesn’t sound too interesting. I did learn something though. It was no real surprise to me that you can get so much information from rocks once I thought about it, but how they do it still surprises me.

The author and his colleagues chose to focus on 375 million year old rocks in their search for fossils because amphibians that look dissimilar to fish were discovered in 365 million year old rocks, while fish without amphibian characteristics were discovered in 385 million year old rocks. Thus, it is possible that the evolutionary intermediary, or the “missing link” between fish and amphibians, would be discovered in 375 million year old rocks, between the two time periods. The rocks examined were sedimentary in composition, as the gradual and relatively gentle formation of sedimentary rock under conditions of mild pressure and low heat are conducive to the fossilization of animal remains. Sedimentary rock is also often formed in rivers and seas, where animals are likely to live. This site provides a resource that describes means by which fossils are formed and how the fossil record may be interpreted, and shows some examples of fossils demonstrating evolution through geological periods: http://www.fossilmuseum.net/fossilrecord.htm. In 2004, Shubin and his colleagues were looking for fossils on Ellesmere Island, in northern Canada. This location was chosen because of its lack of human development, as well as of obstructing natural formations and life forms such as trees, which

Today we are going to learn about the past. We are going to find out what lived long ago. Starting with dinosaurs, plants, animals, birds and bugs my question to you class is how do we know what lived so long ago? The answer is fossils. What is a fossils you ask it is a imprinted, bones and many other proceedings that fossils are apart of life that become lost and later discovered by a us humans in this lifetime. They are so many fossils in this world that even today that we have not discovered, but not every one has the know how to know what is a fossil a university trained who has made it his career as archaeologist expert to find fossil, sure even you could dig up a fossil, but it is up to them to classified the fossil and take care of it so it does not get ruined. Although they are so many types of fossils we still do not know everything there is to know about fossils. The only thing we are sure about is that fossils are what has told us so much and we are still finding new creatures and we are going to see here the how fossil began.

There’s a new digital map limning the composition of the seafloor, and it’s shown evidence of “microfossil” graveyards off the coast of Australia, in addition to other complex deep-ocean geology.

Ocean sediment cores shelled animals (foraminifera) a species living in the world's oceans today around the world. This are used in many different studies, because they have been around since “the Cambrian”, over 500 million years ago and can tell us a lot about past and present sharing of the tropics, locate ancient shorelines, and track global ocean temperature changes throughout the years.

The researchers have discovered dinosaur fossils 10 years ago. It belongs to “Judith,” a spiky headed ancestor triceratops, which trudged the American north-west over 65 million years ago.

*It was first described by Palias (1778) who considered it to be a Mollusc and named it Limax lanceolatus. *Costa (1834) described it as a chordateand named it as ‘Branchistoma’. In 1836, Yarrell (1836) named it as Amphioxus lanceolatus. *Amphioxus is about 1-2 inches long, marine organisms usually found in shallow parts of temperate or tropical seas buried in sand with only the head protruding above the sand surface.

Found throughout the world’s oceans. They are small singe-celled organisms that look like a shell; they are made of a calcium carbonate. How they were made depends on the temperature of the water that they were in or if they were or weren’t by a large polar ice sheet. Through this scientists are able to estimate the temperatures of the oceans and whether there was a polar ice sheet through analyzing the shells

Like all other brachiopods Neospirifer were an exclusively marine fauna. Neospirifer have been found throughout many shallow shelf environments from the Carboniferous and Permian periods. In their adult forms they were attached to the substrate by a fleshy pedicle extending from the larger or ventral valve making them epifaunal and sessile organisms (Kaesler, 2006). The two valves were opened and closed through the use of internal muscles while teeth and sockets held the valves closed. Unlike bivalves brachiopod valves are not symmetrical and show bilateral symmetry (figure 2).

Sponges are one of the most primitive, ancient types of multicellular animal. The vast majority are marine, but a few species dwell in fresh water. Sponges are often found attached to rocks, reefs, or other animals, and feed by straining granular particles from the water. Their frequently irregular body shape can be rather large because their interlocking spicules form a harder skeleton, which are often found preserved as fossils. Sponges are made up of only a few varieties of cells, some cells are unique to a specific phylum and do not have a genuine nervous, digestive, or circulatory systems. For these reasons, they are not immediately ancestral to more complex animal

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.

Beginning about 1850 Ma, we find acritarchs, spherical microfossils with thick and complex organic walls. They are probably dinoflagellates that spent most of their life floating in the plankton.