1. The Missing Link Between Amphibians and Fish 2. The Fossil of Tiktaalik 3. Evolutionary History 4. Mammals 5. Darwin Theory 1.) The author and his colleagues chose to focus on 375 million year old rock because they believed the missing link between amphibians and fish would be located in them. The rocks examined by the author and his colleagues were sedimentary rock, which are most often found in rivers and seas. 2.) The fossil of Tiktaalik had fins and scales, while also having a flexible neck, a flat head, and a complex bone structure. The discovery of Tiktaalik confirmed the evolutionary transition between aquatic and terrestrial life. 3.) The evolutionary history of humans corresponds with that of Tiktaalik, as we share many similarities structures and features of our anatomy. These commonalities between our genetic material underlie a chain of descent between fish and humans. 1.) The pattern discovered by Sir Richard Owen displayed a common bone positioning among all mammals, as they all had the same order of connection. This relates to his idea of exceptional similarities as it correlates to the idea that the bones of animals have a similar fundamental design. 2.) Charles Darwin’s theory stated that organisms that share similarities share a common ancestor. 3.) Further examination of Tiktaaliks fin’s lead to the discovery that the fish had wrists, which allowed it to move through water and on to land. Chapter 3 1.) During the 1950s and 1960s, Edgar Zwilling and John Saunders examined the effect cutting and moving tissues of chicken embryos would have on the development of the embroyo. Zwilling and Saunders discovered two patches of tissues that controlled the development of limbs and tested the effects of its removal at different points during the embryos life. 2.) The Hedgehog gene controls the development of different appendages in all limbed organisms. In chickens, the hedgehog gene is located in the wing bud, and controls the development of pinky and thumb digits. Inn Humans, the gene is located in the arm of an embryo in the eighth week of embryo development and controls the development of arms, wrists, and hands. Chapter 4 1.) Teeth contain high amounts of Hydroxyapatite within them, making them stronger and more likely to fossilize rather than decay. Conodonts are organisms with spikes protruding from their bodies, with Lampreys being an extinct species containing them. 2.) Shubin claims that the creation of teeth allowed for the creation of hair, feathers, and breasts as they all are developed from the ecdoderm.
Dr Donion found out from the sample tests that the bones were influenced by a strong marine diet. Remains of a small fish bone were also found inside his belly, which was most likely to be his last meal before his death. These matching factors suggest that he lived his whole life in coastal areas. “Coastal dweller,” as she
Ceratopsians and Pachycephalosaurs are closely related in their characteristics. Ceratopsians processed a saddle-shaped boney frill that extended from the skull to the neck and typically had horns over the nose and eyes. The most popular was the triceratops, which could reach over 26 feet and weigh in excess of twelve metric tons. Their frills served as two major functions. It protected the vulnerable neck from being harmed. The second major function that the frill provided was due to the fact that the frill contained a network of blood vessels on its underside, which were used as a means to get rid of excess heat. The Pachycephalosaurs were considered to be bipedal. They were also found to have thick skulls, flattened bodies, and tail that were covered in an array of body rods. Pachycephalosaurs were thought to have been more than fifteen feet long and processed a skull that was surrounded by a rounded dome of solid bone. It was thought that they used their heads in combat or mating contests, but that was disproved fairly recently, which I will discuss later in the paper. Both Ceratopsians and Pachycephalosaurs were “bird-hipped” and both of these suborders contained a backwards pubic bone. Both were Marginocephilia, or “fringed heads”, which is one of three clads under the Orinthiscia order. They were also herbivore dinosaurs that inherited their fringe at the back of the skull from earlier ancestors.(2) Their classi...
In the passage "Bone Wars", there are three main central ideas. These ideas, which are supported by factual evidence, build the story between two rivals. Edward Cope and Otheniel Marsh created great controversy in the field of paleontology but left a lasting impact during their lifetime and in today's scientific research.
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
5) What are Dryomomys and why are their important from a biological anthropology perspective? What do these fossils tell scientists about early primate evolution?
The article from Science News, “Telltale Dino Heart Hints at Warm Blood”, by Tina Hesman and the Journal article it was based on from Science, ”Cardiovascular Evidence for an Intermediate or Higher Metabolic Rate in an Ornithischian Dinosaur”, by Paul Fisher and others both offer a new perspective on the topic to be discussed, however there are some key differences between the two articles. How the two articles differ will be discussed later on in the paper. Both of the articles discuss the finding of a heart in a dinosaur that when studied challenges a common belief about dinosaurs hearts.
Although the Hippocampus spp. are placed into the same class as other organisms more traditionally viewed as fish, their morphology bears distinct differences in comparison to other bony fish. The various species belonging under the genus Hippocampus range in maximum size from 20 mm to 300 mm(Foster 8). Their physical appearance is distinct from other members of its class due to their "horse-like head, monkey-like tail, and kangaroo-like pouch."( Lourie et al 12) Morphologically, seahorses do not have scales like traditional fish, but rather posses bony plates covered by skin. The appearance of bony extrusions and skin ...
very sickle shaped dorsal fin. Even though the blue whale is large and seems easy to document,
The origin of modern day whales, a mystery that has puzzled paleontologists for years, may have just been solved with the discovery of an ankle bone. This discovery might sound simple and unimportant, but the bones of these ancient animals hold many unanswered questions and provide solid proof of origin and behavior. The relationship between whales and other animals has proven to be difficult because whales are warm-blooded, like humans, yet they live in the sea. The fact that they are warm-blooded suggests that they are related to some type of land animal. However, the questions of exactly which animal, and how whales evolved from land to water, have remained unanswered until now.
The debate of whether dinosaurs were cold blooded or warm blooded has been ongoing since the beginning of the century. At the turn of the century scientists believed that dinosaurs had long limbs and were fairly slim, supporting the idea of a cold blooded reptile. Recently, however, the bone structure, number or predators to prey, and limb position have suggested a warm blooded species. In addition, the recent discovery of a fossilized dinosaur heart has supported the idea that dinosaurs were a warm blooded species. In this essay, I am going to give supporting evidence of dinosaurs being both warm and cold blooded. I will provide background information on the dinosaur that was discovered and what information it provides scientists.
Mojetta wrote about prehistoric sharks, and the history of these creatures. According to Angelo Mojetta, author of Sharks, Cladoselache genus, one of the first prehistoric sharks, was buried in sediment that kept it preserved. Unlike other sharks, Cladoselache genus had a circle of tiny plates around it’s eyes for protection against it’s victim’s attempts to fight back. These sharks lived over 400 million years ago. Sharks of the past could mostly be identified by their teeth, because shark’s bodies are made of cartilage. Another shark that was focused on was called, Stethacanthus. This shark had a very unique look. Stethacanthus had a brush like decoration on the top of it’s head, and an extra fin like part that had the same bristle like decorations on it. These characteristics were thought to be used as suction cups, to hitch rides from larger fish. One of the most famous sharks that looks like an over...
The disaster theory, Gould claims, is an example of good science. It has testable evidence and has an impact on studies in other fields of science, it develops further and explains why the extinction of dinosaurs occurred simultaneously with other events. This theory suggests that a large comet hit the Earth sixty five million years ago, causing the cloud of dust to rise into the sky and to block sunlight. As a result, world temperatures went down significantly, the ice age bega...
He realized that snake embryos had bumps where there should be legs. Which mean they probably evolved from a creature with legs. He noticed that whale embryos had teeth, but adult whales did not have teeth. The most shocking of his embryotic studies involved human embryos. He noted that the human embryos as slits around the neck, the same in fish. The difference is that in fish the develop into gills, and in human the become the bones of the inner ear. This showed that humans must be descended from fish. This led him to the conclusion that all species were somehow connected. He theorized that beginning with a common ancestor, species had changed dramatically over generations. Some species may add new body features, or lose them. He called this descent with
The evidence for human evolution begins with the australopithecines. All the australopithecines were bipedal and therefore possible hominines. In details of their teeth, jaws, and brain size, however, they modify enough among themselves to be divided into five species: Australopithecus anamensis, A. afarensis, A. africanus, A. robustus, and A. boisei. Genus Homo are also divided in five different spices: Homo erectus, H. habilis, H. sapiens, and H. sapiens sapiens.