A Comparison of Historically Significant Fossil-Lagerstätten
Lagerstätten are fossil-bearing assemblages that, in most cases, contain exceptionally preserved specimens. These assemblages are useful in recreating paleoenvironments and are considered to be windows to the past. Two types of Lagerstätten are recognized: concentration and conservation. Concentration Lagerstätten are useful in determining the composition and reconstruction of food webs. These sites are determined to be true concentration Lagerstätten if they demonstrate a mechanism of concentration rather than merely presence of diversity (Nudds & Selden 2008). Conservation Lagerstätten demonstrate exceptional preservation of organisms in what is known as conservation traps (Nudds & Selden 2008). There are several famous Fossil Lagerstätten worldwide, two of which will be the focus of this paper. They are echinoderm Lagerstatte in the Upper Ordovician succession of the Craighead inlier in southwest Scotland called the Lady Burn Starfish Bed and the Lewiston Member of the Rochester Shale Lagerstätten.
The Lady Burn Starfish beds are located in Scotland and were discovered by the paleontologist Elizabeth Gray (Donovan et al., 2002). This bed is comprised of at least three units known now as the Ashgillian and were deposited just before the first extinction in the Late Ordovician (Nudds & Selden 2008). The beds contain diverse collections of invertebrate and rare vertebrates that not only include echinoderms but also trilobites, possible fish spines, molluscs, and brachiopods (Nudds & Selden 2008).
It has been proposed that the Lady Burn Starfish beds were the result of tsunami deposits however conflicting hypothesis indicate a deep-water, slope environment ...
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.... The purpose of studying the different taxonomic diversity is to recognize changes in community complexity over time (Taylor & Brett 1996).
Appendix
Examples of the exceptional preservation of echinoderms within the Lady Burn Starfish Beds (Nudds & Seldon 2008, p 154)
References
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The shelf-edge includes carbonate-to-clastic facies transition and tectonic uplift and erosion of the carbonates followed by deposition of the clastics. The Saint Peter Sandstone is a well-sorted, almost pure quartz arenite deposited during a major mid-Ordovician low stand. Clastics spread across an exposed carbonate platform by transportation. This is shown by the well-rounded, frosted texture of the quartz grains.
T. californicus is found from Alaska to Baja in small, shallow tidepools and tidal flats in the upper spray zone where they cannot avoid the full effect of visible and ultraviolet (UV) radiation. Individuals assemble in areas of lower radiation at midday, yet have no preference to the intensity of light at dawn and dusk (Hartline and Macmillan 1995). These tiny arthropods inhabit all types of marine sediments from sand to fine mud and ooze. Along with plankton, T. californicus eats microscopic algae, protists, bacteria, diatoms, algae and microbes (McGroarty 1958). When the concentrations of the species in their habitats are high, T. californicus will turn to cannibalism for a food source. The nautilus eye present in the species is rich with fatty acids and provides a good food source for the animal.
...ts were labelled with the upper case letters which represented the material types and a numeric letter. The artifacts were placed in different boxes. The artifact analysis was then conducted and the characteristics such as tool type and material type of each artifact were recorded on the artifact catalog forms. The material samples of lithic tools, faunal remains, and ceramics remains were compare with existing artifacts to identify their material type. The Vernier scale was used for the measurements of each lithic tools.
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Some research has reported finding insects fossilized in amber, containing species such as a termite (30 million years ago), and a weevil from approximately 130 million years ago. These are extraordinary findings, but of course disputed. ...
Andrea Fildani and Michael Shultz, graduate students in the Department of Geological and Environmental Sciences, uncovered the bones of an Ichthyosaur near the southernmost tip of Chilean Patagonia. These rock layers were initially deposited at the floor of an ocean more than 100 million years ago. In their findings of the Chilean boulder, they were fortunate enough to find 17 vertebrae along with neural arches that encircle the spinal cord as well as some ribs. Paleontologists firmly agreed with Fildani’s notion that the bones had been 8 to 9 feet long and had existed around 140 million years ago (Mason 1).
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When we say "coral" we are actually referring to these animals and the skeletons they leave behind after they die. Although there are hundreds of different species of corals, they are generally classified as "hard coral" or "soft coral". Hard corals grow in colonies and are the architects of coral reefs. They include such species as brain coral and elkhorn coral. Their skeletons are made out of calcium carbonate (also known as limestone) which is hard and eventually becomes rock.
The concept of transitional species is an important and complex notion in evolutionary biology. To begin with, there is no such thing as transitional species since all living things were always evolving in the past, not stopping at one stage or another, and they will continue to evolve in the future. In terms of evolutionary biology, we use the concept of transitional species as a way to dim ambiguity. Much like the use of the Linnean taxonomic system of species, we come up with concepts like transitional species to organize and classify species in order to understand their evolutionary roots and how those species changed through life’s history to become what they are today. “In the same way that the concept of species can be provisionally meaningful to describe organisms at a single point in time, the concept of transitional species can be provisionally meaningful to describe organisms over a length of time, usually quite a long time, such as hundreds of thousands or millions of years” (111). Though it can be difficult to distinguish what can be considered an ancestral species from another, the fossil record can show us how species change through time as they develop ways to adapt to stresses found in their environments. “In the modern sense, organisms or fossils that show intermediate stages between ancestral and that of the current state are referred to as transitional species” (222). The concept of transitional species is, in essence, fairly straight forward. This paper will outline the concept of transitional (or sometimes termed intermediate) species and the latter’s role in evolutionary biology, as well as go in depth about several common transitional species: Tiktaalik, an animal at the cusp between life in the water and ...
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The coral itself is made up of the skeletons of tiny, flowerlike water animals called polyps, held together by a limestone substance produced by a type of algae. Hundreds of species of polyps form coral in a beautiful range of colors and shapes.... ... middle of paper ... ...
Smithsonian National Museum of Natural History (2014). Burgess Shale Fossil Specimens. Retrieved May 2014, from http://paleobiology.si.edu/burgess/burgessSpecimens.html
...tes on the path that the modern biodiversity movement has taken in the last two decades. Wilson does seem to think that we are going in a somewhat right direction, and he acknowledges that scientists have discovered many species in the time between the two publishings of his book. However, he asserts that although modern technology has given us a better shot at finding more species, the combined level of effort being put forth by humans is too low to make enough of an impact. The tone that Wilson uses throughout the main part of the book is very similar to the one he uses in the updated preface, meaning that his opinions have not really changed since the original printing. This is good evidence to support the idea that The Diversity of Life is still a relevant text, as his tone would likely have been noticeably different had the movement completely changed gears.
Coral reefs need to be preserved for many reasons. In this paper, I will discuss a few of them. First of all, they house a collection of diverse organisms, and contribute to fisheries which provide food items such as fish, crustaceans, and mollusks. Furthermore, coral skeletons are being used as bone substitutes in reconstructive bone surgery and may be able to provide important medicine, including anti-cancer drugs and a compound that blocks ultra-violet rays, they even help reduce global warming by taking carbon dioxide out of the air. These reefs provide a habitat for many species.