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Evolution Explained The most fundamental concept is that living things change over time. These changes can assist the organism survive and reproduce, or better adapt to its environment. Scientists have employed genetics, a new science to explain how evolution occurs. They also utilized physical science to determine the amount of energy needed to trigger these changes. Natural Selection To allow evolution to take place for organisms to be capable of reproducing and passing their genetic traits on to future generations. Natural selection is sometimes referred to as “survival for the strongest.” But the term is often misleading, since it implies that only the strongest or fastest organisms will be able to reproduce and survive. The most well-adapted organisms are ones that are able to adapt to the environment they live in. Additionally, the environmental conditions are constantly changing and if a population is not well-adapted, it will be unable to sustain itself, causing it to shrink or even extinct. Natural selection is the primary component in evolutionary change. This happens when desirable phenotypic traits become more common in a population over time, resulting in the evolution of new species. This process is driven primarily by heritable genetic variations of organisms, which is a result of mutations and sexual reproduction. Selective agents may refer to any element in the environment that favors or dissuades certain characteristics. These forces can be physical, like temperature or biological, like predators. Over time, populations that are exposed to different selective agents could change in a way that they do not breed together and are considered to be distinct species. While the concept of natural selection is straightforward, it is difficult to comprehend at times. The misconceptions regarding the process are prevalent, even among educators and scientists. Surveys have shown that there is a small connection between students' understanding of evolution and their acceptance of the theory. Brandon's definition of selection is restricted to differential reproduction, and does not include inheritance. However, several authors, including Havstad (2011) has claimed that a broad concept of selection that captures the entire process of Darwin's process is sufficient to explain both adaptation and speciation. In addition there are a lot of instances where a trait increases its proportion within a population but does not alter the rate at which people who have the trait reproduce. These situations may not be classified in the narrow sense of natural selection, however they may still meet Lewontin’s requirements for a mechanism such as this to function. For example, parents with a certain trait could have more offspring than parents without it. Genetic Variation Genetic variation refers to the differences in the sequences of genes between members of a species. Natural selection is among the main forces behind evolution. Variation can occur due to mutations or the normal process in the way DNA is rearranged during cell division (genetic Recombination). Different genetic variants can cause distinct traits, like the color of eyes fur type, eye color or the ability to adapt to unfavourable conditions in the environment. If a trait is beneficial, it will be more likely to be passed down to future generations. This is referred to as a selective advantage. A specific kind of heritable variation is phenotypic plasticity, which allows individuals to alter their appearance and behavior in response to environment or stress. These changes can enable them to be more resilient in a new habitat or take advantage of an opportunity, for instance by growing longer fur to protect against the cold or changing color to blend with a specific surface. These phenotypic variations do not alter the genotype and therefore are not considered as contributing to evolution. Heritable variation is crucial to evolution since it allows for adapting to changing environments. It also allows natural selection to operate by making it more likely that individuals will be replaced by those with favourable characteristics for the particular environment. In certain instances however the rate of transmission to the next generation may not be enough for natural evolution to keep up with. please click for source , like genetic diseases, remain in the population despite being harmful. This is due to a phenomenon called reduced penetrance. This means that some individuals with the disease-associated gene variant do not exhibit any signs or symptoms of the condition. Other causes include gene by environmental interactions as well as non-genetic factors such as lifestyle or diet as well as exposure to chemicals. To understand why some negative traits aren't eliminated through natural selection, it is essential to have an understanding of how genetic variation influences evolution. Recent studies have shown genome-wide association analyses which focus on common variations do not provide the complete picture of disease susceptibility and that rare variants are responsible for an important portion of heritability. Additional sequencing-based studies are needed to catalog rare variants across worldwide populations and determine their effects on health, including the impact of interactions between genes and environments. Environmental Changes Natural selection drives evolution, the environment affects species through changing the environment in which they live. The famous story of peppered moths demonstrates this principle—the white-bodied moths, abundant in urban areas where coal smoke blackened tree bark and made them easy targets for predators, while their darker-bodied counterparts prospered under these new conditions. However, the opposite is also true: environmental change could alter species' capacity to adapt to the changes they encounter. Human activities are causing environmental changes at a global level and the consequences of these changes are irreversible. These changes impact biodiversity globally and ecosystem functions. They also pose serious health risks for humanity, particularly in low-income countries, due to the pollution of air, water and soil. For instance an example, the growing use of coal by countries in the developing world such as India contributes to climate change, and also increases the amount of air pollution, which threaten human life expectancy. The world's finite natural resources are being consumed at an increasing rate by the population of humanity. This increases the chance that a lot 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, with microevolutionary responses to these changes likely to reshape the fitness environment of an organism. These changes could also alter the relationship between the phenotype and its environmental context. Nomoto et. al. demonstrated, for instance that environmental factors like climate, and competition can alter the characteristics of a plant and shift its selection away from its previous optimal match. It is therefore important to understand how these changes are shaping the current microevolutionary processes and how this data can be used to forecast the future of natural populations during the Anthropocene period. This is essential, since the environmental changes caused by humans directly impact conservation efforts, as well as for our individual health and survival. As such, it is crucial to continue to study the interactions between human-driven environmental changes and evolutionary processes at an international level. The Big Bang There are several theories about the origins and expansion of the Universe. None of is as widely accepted as Big Bang theory. It has become a staple for science classes. The theory explains many observed phenomena, including the abundance of light-elements, the cosmic microwave back ground radiation and the vast scale structure of the Universe. The simplest version of the Big Bang Theory describes how the universe was created 13.8 billion years ago as an unimaginably hot and dense cauldron of energy that has continued to expand ever since. This expansion has shaped all that is now in existence including the Earth and all its inhabitants. This theory is backed by a myriad of evidence. These include the fact that we perceive the universe as flat, the thermal and kinetic energy of its particles, the variations in temperature of the cosmic microwave background radiation and the relative abundances and densities of heavy and lighter elements in the Universe. The Big Bang theory is also well-suited to the data collected by astronomical telescopes, particle accelerators, and high-energy states. In the early years of the 20th century, the Big Bang was a minority opinion among physicists. Fred Hoyle publicly criticized it in 1949. After World War II, observations began to arrive that tipped scales in favor of the Big Bang. In 1964, Arno Penzias and Robert Wilson unexpectedly discovered the cosmic microwave background radiation, an omnidirectional signal in the microwave band that is the result of the expansion of the Universe over time. The discovery of this ionized radiation with a spectrum that is in line with a blackbody at about 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 an important component of “The Big Bang Theory,” a popular TV show. In the program, Sheldon and Leonard make use of this theory to explain different phenomena and observations, including their research on how peanut butter and jelly are mixed together.