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Theory of natural selection essay
Essays in evolution
Introduction of evolution
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Evolution can be defined as the process through which the characteristics of a species undergo changes over a number of generations through the process of natural selection. There are different mechanisms that try to explain the evolution process and these are mutation, migration, genetic drift and natural selection. However for natural selection and genetic drift to take place there must exist a certain type of genetic variation.
To begin with natural selection can be defined as the process through which organisms that are better adapted to a certain environment survive and produce fertile off springs. Organisms that do not seem to adapt in that particular environment are left out. For natural selection to occur there must be a number of processes that the particular organisms must display and this is in accordance with Darwin’s idea of evolution. To begin with there is the variation of traits. This can be seen through the fact that some organism within a species are different from the others in terms of color, size and other factors. Variations in the genes of these species brings about these differences.
These variations are caused by mutation leading to the development of new alleles in a given population of a particular species. After variation of traits there are differential reproduction. Due to the fact that the off springs produce tend to be more than the number that can be supported by that ecological niche, the struggle for shelter, mates and food is developed the best suited organisms are able to survive and reach maturity. After reaching maturity they can now reproduce fertile off springs that have the genetic complement of the parents. The offspring tend to inherit the traits posed by the parents and thus they a...
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...f these random drift include bottleneck and founder effect (Coyne, 2009).
Bottleneck is known to occur when a population experiences a major decline due to factors brought about by the environment examples of these factors include; earthquakes, tsunamis and other natural disasters that can cause decline in population. These events may lead to a situation where there is genetic diversity thus making the surviving population vary widely with the original population. On the other hand founder effect can be defined as the loss of genetic variation due to the occurrence of a new population that is set up by a small number of individuals whom have disseminated from a larger population. This leads to the prevalence of certain genetic traits since there is no genetic diversity and this may lead to genetic diseases being popular amongst that particular group of individuals.
Biological evolution is a change in the characteristics of living organisms over generations (Scott, 2017). A basic mechanism of evolution, the genetic drift, and mutation is natural selection. According to Darwin's theory of evolution, natural selection is a process in nature in which only the organisms best adapted to their environmental surroundings have a higher chance of surviving and transmitting their genetic characters in increasing numbers to succeeding generations while those less adapted tend to be eliminated. There has been many experimental research projects that relate to the topic of natural selection and evolution.
Natural selection is a theory suggesting that some genetic traits will be more common than another trait in a given environment in which the organisms live in. Natural selection is a slow and gradual process which will happen in the matter of generations of the species. The traits become less or more common depending on the environmental circumstances, in other words, selection pressure.
Natural selection is associated with the phrase “survival of the fittest.” This basically means that the fittest individuals can not only survive, but are also able to leave the most offspring. The selection of phenotypes affects the genotypes. For example, if tall pea plants are favored in the environment, then the tall pea plants would leave more offspring behind, meaning that the offspring will carry tall alleles. Phenotypes that are successful have the best adaptations (characteristics that help an individual to survive and reproduce) to their environment. These adaptation arise from the interactions with living and nonliving aspects of the environment. Some nonliving aspects of the environment are climate, water availability, and concentration of mineral sin the
What is evolution? Evolution in modern terms is fairly easy to understand. Evolution is the theory that life on earth began with a single celled organism that lived more that 3.5 billion years ago that slowly evolved into many diverse creatures over time. When you break down this theory into sections you get 6 factors: evolution, gradualism, speciation, common ancestry, natural selection and nonselective mechanisms of evolutionary change.
Natural and sexual selection are not random processes. If there is no difference between the individuals within the species there would be no selection. Sexual selection is related to mating, it acts on individual’s ability to obtain or successfully copulate with a partner. The idea of sexual selection was introduced by Charles Darwin in 1871; he revealed that there are organisms with traits which are not explained by the concept natural selection, for example the tail of a male peacock. His found two main ways in which sexual selection works, these are intra-sexual competition and inter-sexual selection. Intra sexual competition happens within species, usually between males. They compete against each other to be chosen as a mate by a member of opposite sex. Inter-sexual selection is choosing a mate among the members of opposite sex, usually done by females.
What is evolution? Evolution is the process at which all living things that are around use today that have ancient ancestors in their background. Also, with evolution it allows for use to see how we have similarities as well as differences from all living organisms from the past to the present. By being able to see the similarities as well as differences it shows how overtime we have changed and evolved through the use of evolution. However, the use of evolution involves different mechanisms in order for it to take place.
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.
There are two different parts of natural selection. There is natural selection itself and then there is also non-adaptive evolution. Natural selection deals with the change of allele frequencies because of the change in the environment. The allele frequencies give us an indication of how much variation there is in a population. A population wants more variation because it allows the population to deal
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).
In order for a species to survive, its population has to evolve. Evolution is the process of gradual change driven by natural selection to improve survival. Evolution is the explanation of how life got to its current state. Before the idea of evolution, the Bible gave the explanation of how things came to be, the Theory of Creation. Charles Darwin is credited for developing the theory of evolution.
Charles Darwin has five parts to his theory of natural selection, firstly the “Geometric increase” which claims that “all living things reproduce in great numbers”, meaning that species may survive but not all will survive because, the resources used for survival for instance ,food will not be enough for all living things. “The struggle for existence” because there is a limited number of resources and can only sustain some and not all, not all living things will survive, however the question lies in which living being will survive?. “Variation” is the third part of natural selection which claims that within those living things there are variations within them that will determine whic...
With the studies that Charles Darwin obtained he published his first work, “The Origin of Species.” In this book he explained how for millions of years animals, and plants have evolved to better help their existence. Darwin reasoned that these living things had gradually changed over time to help themselves. The changes that he found seemed to have been during the process of reproduction. The traits which would help them survive became a dominant trait, while the weaker traits became recessive. A good example of what Darwin was trying to explain is shown in giraffes. Long-necked giraffes could reach the food on the trees, while the short-necked giraffes couldn’t. Since long necks helped the giraffes eat, short-necked giraffes died off from hunger. Because of this long-necks became a dominant trait in giraffes. This is what Charles Darwin would later call natural selection.
Many scientists in the past, such as Aristotle and Plato, believed that there were no changes in populations; however, other scientists, such as Darwin and Wallace, arose and argued that species inherit heritable traits from common ancestors and environmental forces drives out certain heritable traits that makes the species better suited to survive or be more “fit” for that environment. Therefore, species do change over a period of time and they were able to support their theory by showing that evolution does occur. There were four basic mechanisms of evolution in their theory: mutation, migration, genetic drift, and natural selection. Natural selection is the gradual process by which heritable traits that makes it more likely for an organism to survive and successfully reproduce increases, whereas there is a decline in those who do have those beneficial heritable traits (Natural Selection). For example, there is a decrease in rain which causes a drought in the finches’ environment. The seeds in the finches’ environment would not be soft enough for the smaller and weaker beak finches to break; therefore, they cannot compete with the larger and stronger beak finches for food. The larger and stronger beak finches has a heritable trait that helps them survive and reproduce better than others for that particular environment which makes them categorized under natural selection (Freeman, 2002).
The evolutionary theory is the concept that species evolve over time through the mechanism of natural selection of survival and reproduction. Natural selection means acting on the assumption that various living organisms were produced by genetic diversity and mutation. The evolution theory may also be referred to as the philosophizing science. This theory states that all phenomena are derived from natural causes and can be explained by scientific laws without reference to a plan or purpose.
The process of evolution comprises of many complex of mechanisms. These mechanisms fundamentally allow the progression of speciation and adaptation to occur. There are 4 common kinds of evolutionary mechanism of change: Natural Selection, Genetic Drift, Mutation and Migration.