Polychaetes are now considered as the most abundant species of marine worms today as we have identified around 10,000 species of them and counting as the technology for marine research is becoming more sophisticated, but HOW LONG DO THEY EXIST?? The existence of polychaeta began during the Pre-cambrian explosion, same age as the the existence of pre-complex life forms such as trilobites and sponges. It was became evident when a fossil of Polychaete was found in a Burgess shale which is located in British-Columbia's Yoho national park near at the Hudson bay. Another evidence is the fossil of Polychaete that was found in a locality named Francis Creek shale formation that is located in the fossil beds of Mazon creek in Illinois, a Midwestern
This formation is a very fine grain Mississippian limestone. To test to see if this was the Bangor formation we used HCL and because there was a reaction we know its limestone. This formation could also be described as gray in color as well as an average thickness of 700 feet. We see the Bangor until stop eight, where we see a very different vertical bedding. Also different at stop eight is the outcrop no longer reacts with HCL. From this we gathered that we had moved into the Hartselle formation. In the Hartselle Formation, Mississippian aged sandstones are dominant. This particular stop had a large amount of jointing. After the Hartselle, we figured the Pride Mountain Formation would be next, however at stop nine we see the Maury Formation present. This stop focused on the rock located inside the creek. Because we were unable to go into the creek to get the strike and dips, we once again had to do a projected orientation. Also found on this stop were natural sulfur springs, easy to notice with the smell that it gives off. The Maury formation consist of Mississippian- Silurian aged shale. At the next stop, stop 10, we encounter the Ft. Payne formation. Although this area location was thickly vegetated, we were able to conduct the acid test and saw that the HCL reacts in some places but not all. From this we concluded that this was the cherty limestone of the Ft. Payne formation. The following stop, 12, we went up section and arrived at the Maury Formation once again. At the final stop, location 13, we see Ft. Payne Formation. All of the metamorphism and deformation in the southernmost Appalachians can be related to the movement of the thrust sheets and stacks (Higgins,
Starved rock and St. Peter Sandstone are an erosional remnant of Ordovician period. These remnants contain Pennsylvanian clastics that survived the washing out of the Illinois River at the end of the Ice Age. Evidence for swift, turbulent, and deep water includes gravel bars and erosional features as high as 160 feet above the current level of the river, massive cross bedded sand, and gravel deposits along the river course.
The author and his colleagues specifically chose to focus on 375 million year old rocks in their search for fossils because this was the time frame that provided fish that would be useful to study from. The 385 million year old rocks provided fish that look too similar to the ones we have now and the 365 million year old rocks have fossils that don’t resemble fish. The 375 million year old rocks, however, provide fossils that show the transition between fish and land living animals.
The first chapter of the book discusses the way we can use fossil records to study the biological world. Fossils are one of the major lines of evidence we use to understand ourselves. Surprisingly, we are able to discover them with a high amount of precision and predictability. In particular, field paleontologists have it easier than it has ever been before due to the current information age. The physical hunt for important fossils, however, is much like it has always been. Three factors limiting the number of useful fossil sites include rock age, type (whether or not it can preserve fossils), and number of exposed rocks. So, it takes a bit of luck to reliably find fossils. Thankfully, rock
Approximately 17 meters thick, Unit A defines the lowest third of the Juniata Formation. Fragments of marine fossils, including bryozoans, brachiopods, and gastropods, are commonly found in the bottom-most portion of this unit of structureless mudstone and quartz arenite. Quartz grains in the sandstone beds of Unit A are typically immature and fine-grained, though the sandstone packages tend to coarsen upwards. Though typically structureless, intermittent bedding of the sandstone and shale packages is observed in this unit, and some areas display
In a study published in Cretaceous Research and conducted in October 2012 by Anthony R. Fiorillo, Thomas L. Adams and Yoshitsugu Kobayashi, evidence of dinosaurs was based on the finding of an unnamed nonmarine sedimentary package of rocks. Found in the Wrangellia Terrane and considered to be Cretaceous age, the rocks are light colored with medium grey shales and indicate a bounty of horsetails, ferns and gymnosperm wood.
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.
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
correct since no fossils evidence has been found in this region. Furthermore, the professor states
There are many feminist theories and each of them is informed by different sources. There is overlap of where various feminists get to their conclusions but there continues to be unending variations. Griet Vandermassen the author of Who’s Afraid of Charles Darwin?: Debating Feminism and Evolutionary Theory seeks to draw feminists attention towards science as a new source of information to help understand women’s roles and to reinforce women’s rights to equality. She outlines her intentions and her reasons for the book and follows it with an exhaustive argument. Comparing her work to other feminist viewpoints especially views from other women in the sciences helps to shed light on the weaknesses of her argument. Vandermassen is unable to
Almost every metazoan phylum with hard parts, and many that lack hard parts, made its first appearance in the Cambrian. The only modern phylum with an adequate fossil record to appear after the Cambrian was the phylum Bryozoa, which is not known before the early Ordovician. A few mineralized animal fossils, including sponge spicules and probable worm tubes, are known from the Vendian period immediately preceding the
My outside source for questions 3 and 4 is a journal by Pat Shipman titled Fossils. This journal was published in The New Scientist Vol. 215, Issue 2876, p. 8-16.
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.
Eliza, in the climax scene vulnerably asks Higgins, why he made her a sophisticated Duchess if her never cared for her, and why did not he thought of the trouble it would make for her, on which Higgins shocking reply says: