Evolution Of A Large Mammal 's Life Cycles

Faith and Surovell hypothesize a statistical analysis will uncover whether a temporally spread out extinction or a quick extinction killed North America’s Pleistocene mammals, a debate that has split paleontologists and archaeologists into two diametrically opposed sides for years. (Faith and Surovell, 2009). The debate on the extinction method has been heated due to the absence of fossil records of 19 of the 35 genera (Faith and Surovell, 2009). Faith and Surovell test whether finding only 16 genera in the fossil record in the terminal timeframe (between 12,000 and 10,000 radiocarbon years ago or between about 11,800 - 9,400 B.C.) is a result of a sampling error, or an extinction happening over a long period of time (Faith and Surovell, 2009).

     Are birds really dinosaurs or are they simply related? That is a question that has gained new life in recent years due to the overwhelming facts the are pouring in from newly found fossils and studies from fossils that have been found in the past. Two groups have formed in the study of this question: those who believe birds are a direct result of dinosaurs and those who feel dinosaurs and birds must have had a common ancestor. Determining which view is correct is a matter of opinion based on fact. The main problem involves the use of cladistics or phylogenetic systematics to group organisms according to characteristics they share. When one looks at dinosaur fossils, he or she may feel that certain

In 1861 Myer also discovered the first archaeopteryx specimen. Researchers state that “archaeopteryx is the oldest known fossil that is accepted as a bird, they are said to date back to one hundred and fifty million years ago which was during the late Jurassic period” (Archaeopteryx, 2014). Archaeopteryx is unique in that it shows characteristics of both reptiles and birds. The reason the species is seen as half reptile and half bird is because it has feathers like a bird, it has teeth which is dinosaur like, and it has a long boney tail. Some other characteristics of archaeopteryx is that it’s hands, shoulders, pelvis, and feet are distinct, not fused. Knowing these different characteristics one can agree that Archaeopteryx can be recognized as an intermediate between birds and reptiles. Archaeopteryx is seen as a clear transition between, two different classes of species, class reptillia and class aves (Kritsky, 1992). This is proof that evolution does exist and it is gradual. Through this species we are able to see that it is the transitional fossil which links dinosaurs to

Save for anteaters and sloths, armadillos are the only surviving families in the Cingulata order. These small mammals, which have a leathery armored shell, measure about 30 inches that include the tail, which is about half their body size. In Spanish, the word armadillo means “little-armored one “because of its appearance. Its shell looks like a body armor and has a number of bands which describes its genera.

In the ‘NOVA LABS; The Evolution Lab,’ we found that creating a phylogenetic tree can show how different species are related to each other. A simple body part, like a vertebrate, can put species into a certain group. This means that history can prove that species do change over time because one branch represents a single species that has had a speciation. When a speciation occurs, over time, more branches appear with more species on each, which creates a tree that has more biodiversity. In ‘The Stickleback Fish - A Story of Modern Evolution’ activity, it states, “The Three-Spined Stickleback is a model organism for studies in evolution.” This means actions, such as breeding Stickleback, can help scientists see how the fish and other organisms evolve because the Stickleback fish has such a short life-span, that they can breed and get results, fast. In brief, history can prove that species do change over time because breeding can show how the Stickleback population has occurred and how different traits can be expressed in the future generations. In the ‘Comparative Anatomy’ activity, we found that when looking at two different species, you can see how they are related because both species can possess similar traits and forms. When comparing different species, you can see how different and similar two species’ bodily structures are. When looking at the bodily structures, you could see how the species has evolved over time and how some body parts stay the same. In short, history can prove that species do change over time because creating phylogenetic trees, breeding species, and comparing body parts can help scientist see who the species evolved from and how these species can continue to

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

This is believed to be a transitional between reptile and bird. However, there are six points that these supporters use with counterarguments with each one. First, this animal had a long bony tail similar to that of a reptile's (Martin). Conversely, most birds have a tail vertebrae in the embryonic stage which eventually forms into the pgyostyle which is an upstanding bone. The second point is that the Archaeopteryx had claws on its feet and feathered forelimbs (Martin). This cannot be used as evidence because many birds, such as the ostrich for example, have claws so it is not just a characteristic of reptiles (Martin). The third argument was that the bird had teeth but yet so did many ancient birds in the Mesozoic (Martin). The fourth statement used is the presence of a shallow breastbone (Martin). Similarly, most modern birds have the same shallow breastbone that are still classified solely as birds. The second last argument for the Archaeopteryx being the transitional fossil is the its bones were not hollow like modern birds but rather solid. This statement cannot be used however because it was discovered in recent years that the long bones in the bird are hollow. The final point and counterargument is that it predates the general arrival of birds by millions of years (Martin). A geologist in 1977 discovered bird fossils in western Colorado that dated as far back as 60-million years

An example would be to compare modern day birds to dinosaurs, which would allow professionals to assemble a phylogeny relating certain characteristics that they may share and how they have evolved over time. Birds are a unique species that have feathers and fused arm bones that are not present in other theropods (Zimmer and Emlem, 2013). The evolution of bird traits began prior to the existence of birds, as theropods would not have been able to use feathers for flight purposes as their arms were too short and unable to lift them off the ground (Zimmer and Emlem,

Previous research, which is almost entirely fossil-based, concludes mammoth mitochondrial DNA can be sorted into 5 haplogroups or 3 major clades. This hypothesis is correct however up until this study was published the timing of the clade evolution of the order in which they evolved was not known.

Chapter 4 examines how biologists use phylogeny to reconstruct the deep past. evolutionary reversal theory is an important to relates ancestral between this organism and others. These organisms are monotreme, and in fact, modern monotremes are the survivors of an early branching of the mammal tree, and a later branching is thought to have led to the marsupial and placental groups. The extinct monotremes Teinolophos and Steropodon were once thought to be a closely related to this organism. Because of the early divergence for the therian mammals and the low numbers of extant monotreme species, this organism is a frequent subject of research in evolutionary

The article studied collagen found in the fossils of ancient South American animals (Laurasian ‘condylarths’) and compared it with the collagen found in animals present today, mainly xenarthrans (anteaters, armadillos and sloths). The author used the data to compile all the animal species into their respective groups (ungulate). Because the author discovered some discrepancies in the fossil records and the morphology previously thought to be true, he is trying to determine a phylogenetic tree using collagen found in fossils of extinct ancestors of South American mammals.

New discoveries have been found that prove the Giraffe family went through two stages of evolution, which involved cervical elongation. New studies done on Giraffe fossils reveals the likely hood of evolution in stages, “first toward the head, then later towards the tail a few million years later,” (Solounias, 2015). There were different species of Giraffe’s that underwent only one stage of the evolution process, and ended up becoming extinct. The modern Giraffe is the only species that have undergone the whole process of evolution. There are other Giraffes who have shorter necks mainly found in Africa, but they attribute their evolution of those species who only underwent one stage of the evolution process. They plan to study the Giraffes

Surprisingly, it is not the fossils’ themselves, or even the fossils’ old age, that makes the discovery unique. The DNA samples from these bones, however, offer valuable insight into the same molecular clock that scientists use to investigate the evolutionary history of animals. Because the “ancient DNA extracted from the frozen Adélie penguin bones was of high quality” (Lambert & Ritchie), scientists were able to analyze any and all major splits between the two discovered lineages. By comparing the DNA of ancient bone samples to samples from modern day living animals, researchers “constructed median networks” in order to “display relationships

*Mammals are characterized by the presence of mammary glands, hair, neocortex region in the brain, and three specialized middle ear bones. *They are warm-blooded and air-breathing animals. *They are adapted for living in a wide range of environments (including the ocean, underground, and land).

Dr. Balanoff and Shuo Wang, using fossils and a big comparative analysis of the animals of today, found the relationship