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Evolution Explained The most fundamental concept is that living things change over time. These changes can assist the organism to live, reproduce or adapt better to its environment. Scientists have employed genetics, a new science to explain how evolution happens. They also have used the physical science to determine the amount of energy needed for these changes. Natural Selection For evolution to take place organisms must be able reproduce and pass their genetic characteristics onto the next generation. This is the process of natural selection, often referred to as “survival of the best.” However, the term “fittest” could be misleading as it implies that only the strongest or fastest organisms can survive and reproduce. The best-adapted organisms are the ones that can adapt to the environment they live in. Moreover, environmental conditions can change rapidly and if a group is not well-adapted, it will be unable to sustain itself, causing it to shrink, or even extinct. Natural selection is the most fundamental factor in evolution. This occurs when phenotypic traits that are advantageous are more common in a population over time, which leads to the development of new species. This process is driven by the heritable genetic variation of organisms that results from sexual reproduction and mutation, as well as competition for limited resources. Selective agents may refer to any force in the environment which favors or dissuades certain traits. These forces could be physical, like temperature or biological, like predators. As time passes populations exposed to various agents of selection can develop different that they no longer breed and are regarded as separate species. Natural selection is a simple concept, but it can be difficult to understand. Uncertainties about the process are widespread, even among scientists and educators. Surveys have found that students' levels of understanding of evolution are only weakly dependent on their levels of acceptance of the theory (see references). Brandon's definition of selection is restricted to differential reproduction, and does not include inheritance. However, several authors such as Havstad (2011) has claimed that a broad concept of selection that encapsulates the entire process of Darwin's process is adequate to explain both speciation and adaptation. In addition there are a variety of cases in which a trait increases its proportion within a population but does not alter the rate at which people who have the trait reproduce. These situations are not necessarily classified as a narrow definition of natural selection, but they may still meet Lewontin’s conditions for a mechanism like this to function. For instance parents with a particular trait could have more offspring than those without it. Genetic Variation Genetic variation is the difference between the sequences of genes of members of a specific species. It is the variation that allows natural selection, one of the main forces driving evolution. Variation can occur due to changes or the normal process through which DNA is rearranged during cell division (genetic Recombination). Different genetic variants can cause different traits, such as eye color, fur type or ability to adapt to adverse environmental conditions. If a trait is advantageous it will be more likely to be passed on to future generations. This is called an advantage that is selective. A particular kind of heritable variation is phenotypic, which allows individuals to change their appearance and behavior in response to the environment or stress. These changes can allow them to better survive in a new environment or take advantage of an opportunity, for instance by growing longer fur to protect against cold, or changing color to blend in with a specific surface. These phenotypic changes, however, are not necessarily affecting the genotype and thus cannot be considered to have caused evolution. Heritable variation enables adaptation to changing environments. It also enables natural selection to operate by making it more likely that individuals will be replaced in a population by those with favourable characteristics for the particular environment. However, in some instances, the rate at which a genetic variant can be passed on to the next generation is not fast enough for natural selection to keep up. Many harmful traits, including genetic diseases, persist in populations, despite their being detrimental. This is due to a phenomenon referred to as diminished penetrance. It is the reason why some people who have the disease-related variant of the gene do not exhibit symptoms or symptoms of the condition. Other causes are interactions between genes and environments and non-genetic influences like lifestyle, diet and exposure to chemicals. To understand why certain undesirable traits aren't eliminated by natural selection, it is important to understand how genetic variation influences evolution. Recent studies have demonstrated that genome-wide association studies which focus on common variations don't capture the whole picture of susceptibility to disease and that rare variants explain an important portion of heritability. Further studies using sequencing techniques are required to catalogue rare variants across all populations and assess their impact on health, as well as the role of gene-by-environment interactions. Environmental Changes While natural selection influences evolution, the environment influences species by changing the conditions within which they live. This is evident in the famous tale of the peppered mops. The mops with white bodies, which were common in urban areas, in which coal smoke had darkened tree barks were easy prey for predators, while their darker-bodied counterparts thrived in these new conditions. However, the opposite is also true—environmental change may influence species' ability to adapt to the changes they face. The human activities cause global environmental change and their impacts are largely irreversible. These changes are affecting global biodiversity and ecosystem function. They also pose significant health risks to the human population especially in low-income nations, due to the pollution of air, water and soil. For instance, the growing use of coal by emerging nations, such as India is a major contributor to climate change and increasing levels of air pollution, which threatens human life expectancy. Additionally, human beings are using up the world's scarce resources at a rapid rate. This increases the likelihood that a large number of people will suffer from nutritional deficiencies and not have access to safe drinking water. The impact of human-driven environmental changes on evolutionary outcomes is a tangled mess microevolutionary responses to these changes likely to reshape the fitness environment of an organism. These changes may also change the relationship between the phenotype and its environmental context. For instance, a study by Nomoto et al., involving transplant experiments along an altitudinal gradient demonstrated that changes in environmental signals (such as climate) and competition can alter a plant's phenotype and shift its directional selection away from its previous optimal match. It is therefore essential to understand how these changes are shaping the microevolutionary response of our time and how this data can be used to determine the fate of natural populations in the Anthropocene timeframe. This is important, because the environmental changes triggered by humans will have a direct impact on conservation efforts as well as our health and existence. As such, it is crucial to continue to study the relationship between human-driven environmental change and evolutionary processes at an international scale. The Big Bang There are many theories of the universe's origin and expansion. But none of them are as well-known as the Big Bang theory, which is now a standard in the science classroom. The theory is the basis for many observed phenomena, like the abundance of light-elements, the cosmic microwave back ground radiation and the massive scale structure of the Universe. The Big Bang Theory is a simple explanation of the way in which the universe was created, 13.8 billions years ago, as a dense and extremely hot cauldron. Since then it has expanded. This expansion has created all that is now in existence, including the Earth and all its inhabitants. This theory is backed by a variety of proofs. These include the fact that we view the universe as flat as well as the thermal and kinetic energy of its particles, the temperature fluctuations of the cosmic microwave background radiation, and the relative abundances and densities of lighter and heavy elements in the Universe. The Big Bang theory is also suitable for the data collected by particle accelerators, astronomical telescopes and high-energy states. In the beginning of the 20th century the Big Bang was a minority opinion among scientists. Fred Hoyle publicly criticized it in 1949. But, following World War II, observational data began to come in which tipped the scales favor of the Big Bang. In 에볼루션 바카라 사이트 , Arno Penzias and Robert Wilson serendipitously discovered the cosmic microwave background radiation, a omnidirectional signal in the microwave band that is the result of the expansion of the Universe over time. The discovery of this ionized radioactive radiation, that has a spectrum that is consistent with a blackbody around 2.725 K, was a major turning point for the Big Bang theory and tipped the balance in the direction of the competing Steady State model. The Big Bang is a major element of the cult television show, “The Big Bang Theory.” Sheldon, Leonard, and the rest of the team employ this theory in “The Big Bang Theory” to explain a range of observations and phenomena. One example is their experiment which describes how jam and peanut butter get squeezed.