Reptiles, the class reptilian, are an evolutionary grade of animals. The reptile family consists of an order and a class one big family of species that has all evolved from one another. These 3 groups being Crocodilian, Squamata, and Testudines. Reptiles have been around for millions of years. The earliest known reptiles originated 340-335 million years ago during the carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. Although there are some reptiles who live on land, water or land and water, reptiles come in all different shapes, sizes, color’s. There are many diverse reptile groups that are extinct due to massive extinction events. Reptiles are a tetrapod vertebrates meaning they have four limbs, or like snakes being descended from for limb ancestors. Most reptiles are oviparous meaning they are egg layers, although there are some reptiles that are viviparous meaning they carry a fetus in there stomach. The crocodilian has 25 species, squamata has over 9,600 species, and the testudines has approximately 400 species.
The crocodilian is an order of a large predatory semiaquatic reptiles who have been around for millions of years. Roughly around 83.5 million years ago is when the crocodilian first appeared, the crocodilian family consists of the alligators, caimans, and the gavial idea family. Crocodilians are a solid massive lizard like reptile, they have long flattened snouts, and compressed tails. Crocodilians are elite swimmers and can also move on land in a “High or Low walk” some smaller species can even gallop. These reptiles have a four chambered heart that is somewhat similar to birds, and have a unidirectional looping system o...
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... fascinating groups on species in the world. Some of these species can live for decades, whether it is turtle’s lizards, snakes, and these animals have dated back to Jurassic park era. Reptiles come in all shapes and sizes, some have scales and some have a shell, but they are all cold blooded animals. All the reptiles fall in an order, some are higher up in the order than others. The classification of reptiles is hard to distinguish unlike other animals because the main evolution time was during the Mesozoic period. Scientist are still studying these amazing creatures learning more and more about the era of which they have originated from. It is amazing to think that some of these creatures’ ancestors were walking around with the dinosaurs at one time. The reptile family consists of an order and a class one big family of species that has all evolved from one another
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...
Reptiles have a low metabolic rate: they consume energy, and therefore oxygen, slowly. According to Robinson (1975), Plesiosauroids were enduring swimmers with lower flipper aspect ratios and drag-causing long necks. Massare (1988) made the same conclusion, since the hydrodynamic properties of the Plesiosauroids indicate the species moved no faster than 2.3 metres every second. Therefore, the species was confronted by a conundrum: it sought to dive hundreds of metres to hunt its prey yet was constrained, by virtue of its body shape, to travel at slow speed. Invariably, the animal would have been required to forgo oxygen for periods of more than a minute, while keeping the presence of mind to hunt.
Dinosaurs are often compared to and resemble modern day reptiles. Scientists will study how these modern day reptiles behave, look, act, and move to draw conclusions on how the dinosaurs would behave, look, act, and move. They also look at the intern make-up of the modern reptiles to predict how the dinosaurs internal make up would be. However, a recent discovery in South Dakota is stirring up some controversy (Hesman). While Mike Hammer was walking around a ranch in South Dakota he stumbled across a “big-eyed” dinosaur that he now refers to as Willo. The thing that caught his eye was the chest cavity of the dinosaur, upon further investigation he found a rock that was preserved in the curve of the dinosaur’s ribs, he was convinced that this rock was once a heart. Hammer then went on to take the dinosaur fossil in for a medical X-ray scan, this X-ray showed evidence that could change how we think about dinosaurs.
“66 Million–Year–Old Dino With A Heart.” Media Kit 17 April 2000. North Carolina University. 2000 <http://www.dinoheart.org/mediakit/index.html>.
Nicholson KE, Harmon LJ, Losos JB. Evolution of Anolis Lizard Dewlap Diversity. PLOS ONE. 2007
The Hall of Saurischian Dinosaurs and the Hall of Ornithischian Dinosaurs are more examples of evolution within vertebrates. However, these two halls do not have much in common with our line of ancestry except for the fact that a backbone and brain case are present; any other things in common with our lineage are but minor details. That is why the AMNH has another hall called Mammals and Extinct Relatives.
Dinosaurs are an extinct group of animals that thrived for 165 million years starting 230 million years ago in the Late Triassic period of the Mesozoic Era. Despite being extinct for the past 65 million years and not being able to study them in their true form, scientists have been able to estimate many different behaviors of dinosaurs. This paper will show that the close study and examination of different types of body and trace fossils, along with animal models, can be provided as evidence to estimate different types of behaviors in dinosaurs. The different types of behaviors examined below will fall into the categories of: mating; reproduction and nesting; social lives; locomotion; feeding; and fighting. To begin, a great deal of information gathered from fossils and compared to living animal models have been used to estimate mating behaviors.
Biodiversity is the variation and amount of species across the globe, or within in a specific geographical habitat. There are three different areas of study within biodiversity; ecological diversity, species diversity and, genetic diversity. Science Book Species diversity is the variety of different organisms and relationships within a specific species, this essay will discuss the declining of species diversity among sea turtles and the implications it has on the worldwide seas. I have chosen to research about the topic because, sea turtles are believed to have been alive during the Jurassic period. However, now all seven sea turtle species are critically endangered or vulnerable, due to human activities such as; commercial fishing, bycatch and, climate change. (WWF, OCEANA, ACTIONBIOSCI)
...ll. This group still remained successful during the Jurassic period and had a wide geopraphic distribution. Other reptiles evolved to not only live on land, but to fly. The earliest known birds appeared during this period; Archaeoteryx being the first to be considered the intermediate between the birds and predatory dinosaurs. It is debated on whether this ancient bird could actually fly or merely glid from tree to tree. Carnosaurus, meaning “meat-eating” is another group of dinosaurs that ruled during the Jurassic. With such large herbivorous prey animals, the correlation of these large predators make sense of why they were so common. An Allosaurus was one of the most common Carnosaurs in North America. Upon finding numerous intact skeletons in fossil beds, it has been reported that the Allosaurus was superficially similar to the later evolving Tyrannosaurus rex.
In the article "How the Snake Lost Its Legs," Carl Zimmer wrote about the common theory of snake evolution is about to be questioned. All vertebrates that live on land whether mammalian or reptilian are known as tetrapods. In most animals these feet evolved into other limbs, like arms for humans and into wings for birds; however, the snake lost its four feet altogether. The only sign that snakes ever had four feet is a remaining hip located within the rib cage. Paleontologists and herpetologists alike find it difficult to retrace the ancestry of snakes. Because of their scales, eggs, and subtle features of the skull, some scientists believe that snakes are descendants of lizards. However, this still does not explain how snakes lost their legs.
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 ...
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.
There are two kinds of species of alligators. There is the American alligator and the Chinese alligator. Many people have a hard time telling the difference between alligators and crocodiles. Alligators are related in the same family as the crocodile, but these two animals are very different. An alligator’s upper jaw overlaps the lower jaw. Alligators have a broad snout while crocodile have a very narrow snout. Alligators have much less aggressive and energetic than the crocodiles. Alligators live in tropical climates and crocodiles live in somewhat colder climates. Their kingdom is Animalia. Their Phylum is Chordata. They come from the class Reptilia. Their order is Crocodylia. Their family is Alligatoridae. Their genus is Alligator and their species is alligator messissipiensis and they are known as American alligators.
Reptiles are vertebrate, or backboned animals constituting the class Reptilia and are characterized by a combination of features, none of which alone could separate all reptiles from all other animals.The characteristics of reptiles are numerous, therefore can not be explained in great detail in this report. In no special order, the characteristics of reptiles are: cold-bloodedness; the presence of lungs; direct development, without larval forms as in amphibians; a dry skin with scales but not feathers or hair; an amniote egg; internal fertilization; a three or four-chambered heart; two aortic arches (blood vessels) carrying blood from the heart to the body, unlike mammals and birds that only have one; a metanephric kidney; twelve pairs of cranial nerves; and skeletal features such as limbs with usually five clawed fingers or toes, at least two spinal bones associated with the pelvis, a single ball-and-socket connection at the head-neck joint instead of two, as in advanced amphibians and mammals, and an incomplete or complete partition along the roof of the mouth, separating the food and air passageways so that breathing can continue while food is being chewed. These and other traditional defining characteristics of reptiles have been subjected to considerable modification in recent times. The extinct flying reptiles, called pterosaurs or pterodactyls, are now thought to have been warm-blooded and covered with hair. Also, the dinosaurs are also now considered by many authorities to have been warm-blooded. The earliest known bird, archaeopteryx, is now regarded by many to have been a small dinosaur, despite its covering of feathers The extinct ancestors of the mammals, the therapsids, or mammallike reptiles, are also believed to have been warm-blooded and haired.
Studying the evolutionary history and adaption for this species is difficult and an ongoing struggle for scientists. It is classified in the order of Chondrichthyes suborder Elasmobranchii and family of Rhincodontidea. The difficulty in tracing this species evolutionary history stems from the fact that its ancestry dates back 245 million year ago to the Jurassic and Cretaceous