Sauropods

Sedimentary rocks interpret dinosaur habitats through encased environmental structures of the past. Through sedimentary rocks, paleoecologists’ can examine the arranged formation of sedimentary structures to specify what type of environment the dinosaurs’ lived in. An example of a specific sedimentary rock structure can be seen through formed weathering and ripple marks by how wind and sand formed distinct patterns in the past layered sediment. These arrangements provide interpretations on the structure of the sediment and the habitat of encased fossils, through modern day comparisons

From both the title of the chapter and the introduction by Dr. Shubin, this chapter begins with a focus on teeth. Because the function of teeth is to break down food before it enters the esophagus, the different shapes of teeth can represent many different things about the organism it belongs to including what type of eater it was (carnivore, herbivore, or omnivore). Teeth are the hardest tissue (not bone) in the human body and therefore fossilize well. As Dr. Shubin stated in chapter one, there must be many points that permit a fossil to make any kind of scientific conclusion. Obviously, the state of their presence is important, so the fact that teeth preserve well allows for them to be great specimens for analysis. Dr. Shubin and his team analyzed fossilized teeth in areas as different as Nova Scotia and the Arizona desert. Studying different fossils in these diverse regions allowed the team to see that mammalian and reptilian teeth are very different. For example, mammalian teeth differ from organism to organism to fit with the organisms need (Cheetahs that eat only meat will have different teeth than deer who are herbivores) and are replaced only once in the lifetime of the organism while reptilian teeth are usually sharp and are constantly replaced if damaged. These differences allowed scientists to characterize fossils as either a reptile or a mammal. Similar to Tiktaalik discussed in chapter one, the discovery of fossils that were part reptile and part mammal allowed the researchers to see that mammals evolved from reptiles, and further supported the theory of evolution. Further studies yielded even more

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.

Fossils provide a record of how organisms have evolved overtime, as they contain the remains of life trapped in sediment, ice or amber and preserved for over millions of years. Transitional fossils, which provide evidence for evolutionary change, have features that show the transition of characteristics of organisms from ancestors to descendents. An example is Archaeopteryx, which featured reptilian features, including teeth and skeleton, however, also had feathers and a wishbone sternum (used to attach muscles for flying). The evidence of the fossil shows the evolutionary transition between dinosaurs and

Most Cambrian rocks contain fossils of trilobite shells, cap-shaped or flattened shells, and brachiopods (Whittington, 1985). When Walcott went looking for North American Cambrian fossils in August of 1909, he ended up in the Canadian Rocky Mountains. He and his wife found a loose block in the ridge they were searching near, split it open, and found what they later classified the “lace crab” (Briggs, 1994). Walcott knew right away what they had discovered was something different – the soft parts of the crab, such as the limbs, were preserved. During the next season, Walcott and his sons came back to the Shale, searching the slopes along the trail where they had discovered the loose block to find fossil layers. Luckily for them, the Shale rock layers were almost horizontal, and for thirty days a team quarried the ridge. The next year, they spent even longer quarrying. The last year spent quarrying the rocks was in 1917, when Walcott was 67 (Briggs, 1994). The rocks were removed from the ridge using picks, chisels, long iron bars, and small explosives. All the quarrying done by Walcott and his crew resulted in over sixty five thousand fossils, now stored in the

Introduction: Fossils are defined as a physical trace or evidence of life from a prior geological time period which has been preserved. Examples of fossils include burrows, indentations or bite marks, footprints or other impressions, coprolites, hard animal body parts such as bone, shells or horns or mineralized plant remains embedded in stratified rock.

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

Dinosaurs come in many different colors and sizes. The lifespan of a dinosaur is 75 to 300 years. Their daily life is hunting, mating, using the bathroom, and migrating. The defense mechanisms helped them repair their injuries 150 mya. The bone structures are the skull, jaws, neck bones, vertebrae, thigh, pelvis, tail, and rib bone. Dinosaur’s average speed is about 27 mph. Dinosaurs find their food by hunting, which is each other and some eat plants. They reproduce by hatching newborns from eggs. Some communicate by their horns or flickering the tip of their tails. Baryonyx stomach contents were found to contain fish scales, is an example of predator-prey relationship. Some animals that are related to dinosaurs are lizards, because of their skin texture.

In the science of paleontology, the history of life is studied. Paleontologists study fossils to learn the past ecologies, evolution, and the origins of humans. In order to understand the processes that have led to both the origination and destruction of organisms since life began, paleontologists incorporate both scientific knowledge and studies. Fossil findings are critically important for confirming predictions of evolution theory. Of the many discoveries that are made yearly to add depth to the understanding of evolution, an example is a recent discovery of a creature they named Tiktaalik. The Tiktaalik was uncovered to be a transitional animal between shallow-water fishes and limbed animals. The creature supports the idea that it emerged from both mammals and reptiles, suggesting that the two are related. These findings support prediction of evolution, contradicting the belief that God

Because dinosaurs are animals that lived millions of years ago, we are entirely dependent on the fossils that they have left behind for any understanding that we hope to gain. As any paleontologist will tell you, fossil hunting is difficult. There are no certainties, no guarantees. A certain amount of luck is as valuable as any scientific knowledge.

Plant fossils and trilobites are often found as casts and molds. Most molds and casts do not contain the actual remains of an organism. Shells, bone, and wood often form as molds or casts. Dinosaur footprints can also be classified as mold fossils. Shells can make an imprint in sand, and under certain conditions such an imprint might be preserved and then filled in. Trace fossils can form if two conditions are met. First, the activity has to take place in a material that will hold its form (like mud or clay). Second, the evidence of the activity has to be well preserved (often by being buried quickly). Common activities that are captured in time as these conditions are met include walking and running (footprint fossils), burrowing (organisms homes can be frozen in time through petrification), and defecating. The animals speed, length of stride, and whether they walked on two or four legs. The bones structure of the foot and the stalking behavior (a carnivore hunting a herd of herbivores).The existence of dinosaur herds and stampedes. How the tail is carried (few tail tracks have been found, so tails were probably held above the ground). Speed, the length of stride and whether they walked on two or four

• Many parts of the skeleton changed as new innovations that permitted life on land evolved. For example, the ancestors lived fully in the water and had skulls that were tall and narrow, with eyes facing sideways and forwards. This allowed them to look around in their watery environments for predators and prey. However, as ancestors of the first tetrapods began to live in shallower waters, their skulls evolved to be flatter, with eyes on the tops of their heads. This probably allowed them to look up to spot food. Then, as tetrapods finally moved fully

Jurassic Park by Michael Crichton demonstrated many dinosaur characteristics and behaviors. The dinosaurs were fictionally characterized to appeal to the readers. By examining the dinosaur’s appearance and behaviors of dinosaurs such as the duckbilled dinosaur, velociraptor, hypsilophodontids, dilophosaurs, Triceratops, apatosaurs, Tyrannosaurus rex, stegosaurs, and maiasaurs distinguished whether the evidence existed in the field of paleontology. The behaviors and characteristics of the dinosaur are divided into three factors as behaviors that were supported, not supported, and no evidence to support or refute the behavior.

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.