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Evolution a complicated process
The process of evolution essay
Evolution a complicated process
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Introduction
Evolution is defined as the process in which there is a change in allele frequency within a population over successive generations, in response to evolutionary forces (Ridley, 2004). The rate of evolution is a measure of how quickly these allele frequency changes take to establish within a population. Evolution is a highly complex process, due to the numerous contributing factors that influence it (Hamilton, 2009). Therefore the rate at which it occurs varies greatly, influenced by a combination of factors such as the mutation rate, the type of mutation, population size and life history traits of taxonomic groups (Frean, 2013). The rate at which evolution occurs is an aspect of Evolutionary Biology that remains highly disputed,
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The first of these is phyletic gradualism, which states that evolution is a slow process that occurs at a fairly constant rate. Speciation is the formation of a new species, which in this theory arise via micromutations. These are small-scale mutations that occur over a period of time at a constant rate. Micromutations accumulate over time and lead to a series of intermediate forms, which transition the ancestor species into a new distinct species (McCabe, 2017).
The contrasting theory is punctuated equilibrium, which states that evolution occurs in disproportionate alternating periods of stasis and punctuation. A lineage will remain in stasis for the majority of the time, in which it is held in evolutionary equilibrium. This is where stabilizing selection is believed to occur, in which selection favours individuals with intermediate variant phenotypes, rather than extreme phenotypes. Stasis can alternate to the punctuation phase, in which stabilizing selection no longer constrains allele frequency changes, allowing for macromutations to occur. These are mutations that have a large phenotypic effect, giving rise to changes in allele frequency. The phenotype produced results in speciation, and the rate of evolution varies between slow and very rapid periods. (McCabe,
Evolution, also known as descent with modification, is a phrase Darwin used in proposing the evolution of Earth’s many species. Charles Darwin noticed that the descendants of ancestral species were different from the present day forms of species. Darwinism is a theory of biological evolution developed by Charles Darwin who was an English naturalist. He expounded the theory of evolution in his book of the Origin Species in 1859. He expresses that all types of organisms emerge and develop through natural selection, small, acquired traits that expands the individuals of capacity, survival, and reproduction. In this book, Darwin theorized that animals and plants evolve and develop with the aid of the creator through the process of natural selection.
[1] This problem with the theory of evolution was addressed by Stephen Jay Gould and other evolutionists. They postulated the punctuated equilibrium theory of evolution, which does not predict the numerous fossils predicted by the orthodox theory of evolution.
The second of Tinbergen’s questions Phylogeny looks at the evolutionary explanations of development, as opposed to just how behaviour has adapted, including mutations in response to environmental changes. Some of these mutations remain in species even after necessity has gone, and can influence future characteristics of that species. The third of Tinbergen’s questions looks at Causation,...
The second part of the theory of evolution is gradualism. Gradualism is the idea that it takes many generations to produce a substantial evolutionary change. An example of this change is birds gaining the ability to fly.
Charles Darwin’s theory of natural selection explains the general laws by which any given species transforms into other varieties and species. Darwin extends the application of his theory to the entire hierarchy of classification and states that all forms of life have descended from one incredibly remote ancestor. The process of natural selection entails the divergence of character of specific varieties and the subsequent classification of once-related living forms as distinct entities on one or many levels of classification. The process occurs as a species varies slightly over the course of numerous generations. Through inheritance, natural selection preserves each variation that proves advantageous to that species in its present circumstances of living, which include its interaction with closely related species in the “struggle for existence” (Darwin 62).
According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
The majority of scientific work in genetics and genomic sequencing has been done in the last 155 years. In 1859, Charles Darwin published On the Origin of Species where he proposed evolution by natural selection. Evolution is the change of inherited characteristics of biological populations over successive generations.Yet, the principals of genetics required to explain how characters are ...
A British naturalist and geologist by the name of Charles Darwin was the first to formulate a scientific argument for the theory of evolution by means of natural selection.Evolution is said to occur over long stretches of time, not in quick jumps. There are actually two different lines of thought on the matter. Phyletic gradualism holds that speciation takes place constantly and over long periods of time. Punctuated equilibrium, on the other hand, involves quick jumps and starts, with long periods of time between the changes.
What is evolution and how does it work? Evolution is the theory of how one form of life changes into another form. Evolution also is the change of a population’s inherited traits from generation to generation. Evolution helps to explain why an animal, human, and plant looks the way it does and acts the way it does; it gives an explanation of the history of life. Genes come in many varieties and the evolution helps to make it happen. Mutation, natural selection, genetic drift, and gene flow: the four forces that make the evolution work.
13.) Evolution - is the development of species ( that is , a group of animals or plants ) Through different stages over many generations.
Extinction, although not as pleasant a concept as the idea of adapting to ones surroundings, plays just as large a role in natural selection as anything else. As one adaptation of a species proves beneficial, and as that variation begins to propagate, the original, less advantageous variant will die off. It is the unchanged species that are in immediate conflict with the species undergoing the natural adaptation that stand to suffer...
Mutations are defined as changes in the genetic sequence. Mutations are main cause of diversity among organisms. Because these changes occur at many different levels, and they can cause widely differing consequences. In order for mutations to affect an organism's descendants, these mutations must: 1) occur in cells that produce the next generation, and 2) also these changes should affect the hereditary material. Finally, the interactions between environmental pressures and inherited mutations generates diversity among species.
The evolution theory, one of the most significant theories, laid groundwork for the study of modern biological science. This theory has lead scientists into unending debates due to lack of empirical supports. Until the mid-eighteenth century, when Charles Darwin came up with an explanation to evolution, scientists, then, began to endorse this hypothesis. In “Natural Selection,” Darwin explains the natural selection, a plausible mechanism that causes evolution, to gain approval of his cynical audience for his evolution theory. He supports his claim with numerous examples of animals and plants that have developed traits beneficial for survival. A century later, Stephen Jay Gould, influenced by Darwin’s work, supports the evolution theory with a different method. In “Evolution as Fact and Theory,” Gould, in contrast to Darwin, criticizes his detractors, the creationists who believe that every life form is the creation of a supernatural being, to reinforce the validity of the evolution theory. Gould undermines creationism by emphasizing its misused concepts of theory and popular philosophy, proving that it is not science. Besides denouncing creationism, Gould also provides theoretical examples as evidence to prove evolution is a theory. Despite their different approaches, both Darwin and Gould effectively prove the existence of evolution.
Without evolution, and the constant ever changing environment, the complexity of living organisms would not be as it is. Evolution is defined as a process that results in heritable changes in a population spread over many generations (8).Scientists believe in the theory of evolution. This belief is based on scientific evidence that corroborates the theory of evolution. In Figure 1 the pictures of the skulls depict the sequence of the evolution of Homo-sapiens. As the figure shows, man has evolved from our common ancestor that is shared by homo-sapiens. The change of diet of homo-sapiens over time has thought to contribute to the change in jaw structure and overall skull shape.
Biological evolution is the name for the changes in gene frequency in a population of a species from generation to generation. Evolution offers explanation to why species genetically change over years and the diversity of life on Earth. Although it is generally accepted by the scientific community, Charles Darwin’s theory of evolution has been studied and debated for several decades. In 1859, Darwin published On The Origin of Species, which introduced the idea of evolutionary thought which he supported with evidence of one type of evolutionary mechanism, natural selection. Some of the main mechanisms of evolution are natural selection, mutation, and genetic drift. The idea that all life on Earth shares a common ancestor has been around for a long time but has risen to significance in society over the last two centuries.