Charles Darwin had two great themes in "On the Origin of Species" which accounted for the similarities and adaptations characteristic of living organisms. To account for the adaptations of organisms and those innumerable features that equip them for survival and reproduction, Darwin (and Wallace) independently came up with the central theory of evolutionary process: natural selection. Natural selection gives insight in to why organisms are the way that they are. Adaptations are phenotypic variants that result in the highest fitness among a specified set of variants in a given environment. In reference to humans, there are many traits that have been selected and adapted for throughout their evolutionary history giving them the characteristics that they have today. In this paper I will discuss some parts of the human body, which have been found to be selected for by the evolutionary mechanisms of natural selection, adaptation and mutation. Natural selection, adaptation, and mutations are three components of the evolutionary process, each one having either positive or negative effects on the other. What exactly is natural selection? There are many variations of the definition but most agree that it must include the following concepts: some attribute or trait must vary among biological entities, and there must be a consistent relationship, within a defined context, between the trait and one or more components of reproductive success, where "reproductive success" includes both survival and the reproductive processes themselves (Futuyma, 1998). Charles Darwin's theory of natural selection states "if variations useful to any organic being ever occur, assuredly individuals thus characterized will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance, these will tend to produce offspring similarly characterized." Regardless of how it is defined, natural selection and its action can have tremendous effects on the members of a population. It is natural selection that causes adaptation, and these adaptations evolve to ensure the survival of a species. Evolution, in a very broad sense, is defined as descent with modification and often with diversification (Futuyma, 1998). Darwin's idea of evolution was that it occurred by descent with modificatio... ... middle of paper ... ...-carbohydrate, high protein diet. Certain metabolic adaptations were therefore necessary to accommodate the low glucose intake. Many indicate that the adaptive response to the low carbohydrate intake is insulin resistance(Miller, Colagiuri, 1994). A study done by J.C. Brand Miller and S. Colagirui proposes that insulin resistance offered a survival and reproductive advantage during the Ice Ages. This study also proposed that a carnivorous diet would have disadvantaged reproduction in insulin-sensitive individuals and positively selected for individuals with insulin resistance. Another factor mentioned was the various environmental factors that contributed to the low carbohydrate intake such as the types of foods that were available. The forces of natural selection on the evolutionary processes in humans can have a broad range of effects on the characteristics of humans. There are no concrete answers to some of the questions proposed in this paper, but time will soon tell exactly how the evolutionary mechanisms have effected the human race. The human species will continue to evolve as long as the mechanisms of evolution and environmental factors act upon us.
This is called natural selection. When the surviving individuals reproduce, it leads to the overall change in their traits and newer generations will possess this trait. The law of thermodynamics states that within an expected natural thermodynamic process there will always be increases in the entropies of the interacting systems. The law also states that the entropy of a system which is isolated without equilibrium will increase over time.
Charles Darwin founded the theory of evolution by natural selection, which according to this principle defines; biological characteristics enhance survival increase in frequency from generation to generation (Larsen et al. 22). These individuals are inclined to produce more sustainable offspring to pass their genes to, meaning that some individuals are more reproductively fruitful than others. Natural selection requires variation in a species, which can result by gene flow, mutation, or genetic drift & also involves environmental stresses such as climate change. These result as the evolutionary means of how certain traits can be selected. Eventually, traits that give individuals certain advantages, such as bipedalism in hominids, will be selected in great numbers & more individuals in a population will display these traits.
“I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection.” - Charles Darwin.
Natural selection was one of the most important discoveries in the Nineteenth century, and it has changed peoples’ position ever since. Natural selection also provides people a new chance to find truth in the world. Even though it has been demonstrated for over one hundred years, we can still try to find new information from it. Today, natural selection is a very important subject that a lot of scientists try to use to explain different kinds of evolutionary questions.
Evolution is the theory that all living forms came from ancient ancestors and is the natural process to improve a species chance of survival. Through a series of mutations, genetic drift, migration, and natural selection today’s descendants show an amazing amount of similarities and diversity. Evolution on a small scale is called microevolution, an example being the
In 1859, Charles Darwin set out his exploration of the evolution by natural selection as an explanation for adaptation and speciation 1859. Darwin characterized natural selection as the rule by which each variety of a trait, if valuable, is safeguarded. Another researcher, Alfred Russell Wallace, came to a similar conclusion, but because Darwin was well-known and respected researcher even before he composed On the Origin of Species, Wallace was obscure and unknown, so individuals were more likely to listen to Darwin. Darwin's theory comprised of two key emphases which were varied gatherings of creatures advance from one or a couple of basic predecessors of adaptation. And the component by which this development happens is natural selection.
Natural selection, or the ability of species to adapt to the dangers of their environment to work towards the goal of reproducing and surviving.
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).
Environmental conditions have stimulated the important developments of how we became who we are today. The development of early humans faced environmental changes and evolved bigger bodies, larger, more complex brains. With having a bigger more complex brain came as an advantaged. Processing and storing a lot of information became easier, it gave early humans the advantage to interact more socially and to become aware with encounters to unfamiliar habitat (Bigger Brains: Complex Brains for a Complex World, 2015).
Evolution is the gradual, continuous change of characteristics throughout a population or a species over many generations. It is the moderation of characteristics that can alter an entire population over a long period of time and is the theory that explains the variation in each generation of an organism.
There were only two faults that he found within her – theater and false jewelry. Lantin didn’t share her love for theater. After attending many performances with her, he finally begged her to go with some lady friends. Her love of theater brought about her love of fake jewelry. Sometimes she would bring out her jewelry in the evenings just to look at them. The theater and jewelry didn’t seem to be affecting them financially in anyway, so why not let her indulge herself in them. She was happy and he was happy.
Natural selection: It is defined as the process of natural adaptation to the environment by the species to survive and their existence through the production of offspring.
Convergent evolution is the process in which organisms which are not closely related derive akin traits separately due to the need for adaptation to similar environments or ecological niches. According to the neo-Darwinian view, species with similar environmental living settings experience similar selection pressures. Natural selection then acts on the arbitrary changes or current genetic variability leading to identical phenotypic solutions. There may be resemblances at a phylogenetic level, but the basic DNA sequences are different. Convergent evolution gives rise to characteristics which are referred to as “analogous structures”. They are often contradicted with “homologous structures” which have the same ancestors. Convergent evolution
Over a long period of time, populations can completely change not just by random factors and situations, but rather by heredity, as they are still the same population but include different genes (“Descent Through Modification,” n.d.). A form of evolution misconstrued to be based on ‘chance’ but is indeed influenced by non-random selection includes mutation through heredity and evolution to show non-random processes of populations (“A Mutation Story,” n.d.). By accumulating and observing data from multiple real-life situations, it is shown that selective adaptation plays a large factor in the process of evolution and how complex and diverse species
4) Selective pressure-An environmental factor that causes individuals with certain traits, which are not the norm for the population, to survive and reproduce more then rest of the population. The result is a shift in the genetic makeup of the population