Evolution is a theory that argues that all organisms alive on earth today share a common ancestor. It is thought that through generations, specific changes or adaptations were established in species in order to help them survive, reproduce, and raise offspring. But how are we certain that these changes occurred? Before, life on Earth was driven by carbon dioxide not until oxygen became plentiful and underwater invertebrates slowly started to adapt it into their system. 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 earliest tetrapod known is Acanthostega. It is also considered the most primitive tetrapod. It is very close to its fish ancestry, but still anatomically far from its terrestrial relatives. These creatures still lived in water, but they had a lot of the terrestrial tetrapod anatomical characteristics. Introduction: Before tetrapods existed, all vertebrates were confined to living in aquatic habitats.
The Future of Human Evolution Evolution, the science of how populations of living organisms change over time in response to their environment, is the central unifying theme in biology today. Evolution was first explored in its semi-modern form in Charles Darwin 's 1859 book, Origin of Species by means of Natural Selection. In this book, Darwin laid out a strong argument for evolution. He postulated that all species have a common ancestor from which they are descended. As populations of species moved into new habitats and new parts of the world, they faced different environmental conditions.
Primitive character is the feature of a group of organisms that is inherited from a common ancestor. In order words, an organism must share the same primitive character to be included in the group. Derived or secondary characters are features that are not shared with all organisms in a larger group because they evolve after the primitive character. From analyzing the fossil evidence, experts have discovered that early tetrapod amphibians evolved from lobe-fin fish. Amphibians are cold-blooded vertebrates animals that live under water and on land.
Paper Topic This paper will discuss the various features that distinguish amphibious tetrapods from their fish ancestors. It will also be considered how these features made amphibious tetrapods better adapted for land living, subsequently leading to the tetrapod invasion of land. Introduction 425 million years ago, during the Silurian period, the first terrestrial plants began to invade the land. 15 million years after this, in the late Silurian Period, the first arthropods, in the form of millipedes joined plants in the invasion of land. However, it wasn’t until the late Devonian Period, 350 million years before present time, that the first vertebrates began to invade the land.
One of the most important principles of biology is the main idea of evolution. This theory states, “that all living organisms have evolved from a common ancestor through natural selection acting on hereditary variation” (Reece, 2011). Many people today, know humans have evolved from a common ancestor; but they do not recognize the importance of it. Everyone should be educated about how organisms evolved because humans have evolved throughout many centuries. Charles Darwin had many theories that incorporated the main principle of biology, natural selection and evolution.
The early Devonian period is largely considered to be a world of a diverse array of lobe-finned fish, including lungfish, coelacanths, and bony fish. Over the course of time, vertebrates made evolutionary strides with provided them with the ability to travel on land. Coelacanths developed a single boned shoulder girdle, lungfish developed paired fins, and sauripterus developed the major structures on the arm (humerus, radius, and ulna). As these developments progressed and environmental pressures were amounting in aquatic environments, vertebrates began to venture onto land. Sometimes it was for short excursions, sometimes a bit longer.
Evolution is defined as the process by which different kinds of living organisms are thought to have developed and diversified from earlier formed during the history of the Earth. Evolution is the reason we have so many different species. The basis of evolution comes from survival of the fittest. Those who do survive create an offspring even more fit for survival. The process of natural selection supports the idea of survival of the fittest and plays a key role in evolution.
If there was Creation (Special), the species would have been anywhere the condition and environment was suitable. In addition, many animal fossils have been discovered that show us how evolution lead to us. Tiktaalik roseae is the name of a newly discovered lobe-finned fossil fish from the late Devonian period, which is a transitional form to amphibians. It had basic wrist bones and simple fingers, as well as the robust ribcage necessitated by existence out of water. Evolution is the only possible explanation for this that makes sense.
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.