Through fossil records scientist have evidence that show how anatomical and physiological alterations occurred to species that caused them to turn from aquatic animals to terrestrial animals. The following are gradual changes that took place in species respiratory system, and will allow some underwater invertebrates to transform to land-dwelling vertebrates through evolution. It is said that fish were amongst the first species to live on Earth. The first invertebrates on Earth were jawless fish that used gills to breathe underwater, which are capillary-filled flaps near the mouth. When water flows over the gills, the blood in the capillaries exchanges carbon dioxide for oxygen; a process known as gas exchange.
Abstract: The early tetrapods were the first vertebrates to actually walk the solid earth. They began their conquest of land in the Paleozoic era around 360 million years ago. The question many paleontologists have been asking for a long period of time is whether the anatomy for locomotion on land was developed in water for swimming purposes, or if it was adapted after the creatures became terrestrial. Recent findings of fossils indicate that the transformations of the aquatic creatures happened underwater in order to help them survive in the changing world. When looking for answers, they had to examine forearm, hip, wrist, finger, and other bones, as well as the lungs or gills of the early tetrapod fossils.
It is said that fishes were amongst the first vertebrates. The earliest fish to appear in the fossil record were jawless, covered with bony plates, gills, scales, but no fins. According to Arreola, they later evolved by adapting to their environment and began to form jaws and paired fins. The jaws were useful with their muscles and teeth, which helped them eat a wider variety of food, and were even able to defend themselves by bi... ... middle of paper ... ...is a form of evidence that shows how life has changed throughout the years and how species today are connected way back to a common ancestor. Paleontologists look for features from one way of life to another.
However, it wasn’t until the late Devonian Period, 350 million years before present time, that the first vertebrates began to invade the land. These early vertebrates came in the form of amphibious tetrapods, organisms that had evolved from lobe finned fish. Although by their appearance these amphibious tetrapods may appear vastly similar to their fish ancestors, when looking at skeletal morphology of these creatures, one can see several distinct and major differences. It is these changes that will allow amphibious tetrapods to thrive on land, and set a base from the future evolution of reptiles, dinosaurs, mammals, and eventually humans. Skull Morphology As lobe finned fish began to evolve features that were better suited for living on land, one can see many changes taking place in the morphology of their skulls.
Rock layers are an evidence of evolution because they show the development of life through fossils, show how rock layers relates to evolution, and can explain why the continent Pangea split into the continents we have today. Rock layers are like a portal through time, they show how animals looked in past and evolved through time. In these layers we see fossils, “petrified” and “preserved” forms of old organisms (Google). Scientists have seen and uncovered many different fossils and some have looked similar but from different depths in the layers. Scientists have found fossils of fish, reptiles, amphibians, mammals, birds, today’s mammals, and dinosaurs.
Ultimately, fish behavior is a product of bioenergetics. First, we will take a look at basic fish bioenergetics, understanding the underlying quantitative principles. Then, we will look at some examples of how physical forces, thermodynamics, and light characteristics are specifically related to fish bioenergetics. Most of these models and ideas are made under the assumption that there is no predation or competition, which are additional factors that will influence behavior. Fish bioenergetics includes components of physical forces, thermodynamics, and light characteristics, and follows energy laws and theories describing any other closed system.
This recurrent pattern in vertebrate land animals can be explained by descent from a common ancestor that had limbs bones laid out in the same manner. It then follows that there should be a fossil of this common ancestor that indicates the transition between finned fishes and limbed amphibians. Not unexpectedly, Tiktaalik, a perfect intermediate was found in a rock of appropriate age. It has a flattened head, and a neck which is seen in land animals and the one bone-two bones-lotsa blob-digits pattern in its fins. It also has scales and webbed fins, which are characteristic of fish.
Thoeries of Evolution Evolution is the process by which living organisms originated on earth and have changed their forms to adapt to the changing environment. The earliest known fossil organisms are the single-celled forms resembling modern bacteria; they date from about 3.4 billion years ago. Evolution has resulted in successive radiations of new types of organisms, many of which have become extinct, but some of which have developed into the present fauna and flora of the world (Wilson 17). Evolution has been studied for nearly two centuries. One of the earliest evolutionists was Jean Baptiste de Lamarck, who argued that the patterns of resemblance found in various creatures arose through evolutionary modifications of a common lineage.
It is possible that all organisms can be traced back to the origin of Life from one celled organims. The most direct proof of evolution is the science of Paleontology, or the study of life in the past through fossil remains or impressions, usually in rock. Changes occur in living organisms that serve to increase their adaptability, for survival and reproduction, in changing environments. Evolution apparently has no built-in direction purpose. A given kind of organism may evolve only when it occurs in a variety of forms differing in hereditary traits, that are passed from parent to offspring.
Physical anthropology deals with the evolution of humans, their variability, and adaptations to environmental stresses (Cruz, N.D). Using an evolutionary examine not only physical form of humans, bones muscles and organs but also how it functions to allow survival and reproduction (Cruz, N.D). Paleoanthropologist studies the evolution of primates and hominids from the fossil record and from what can be determined anatomy and studies of social structures and behavior from our closet living relatives (Cruz, N.D). In doing so paleoanthrologists work with geologists, palezoologists, and scientists with other specialties who help them reconstruct ancient environments (O’Neil, 2009). Evolutionary scientists as “hominins” classify humans, chimps, and all of the organisms leading back to their supposed most recent common ancestor.