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Evolution Explained The most fundamental notion is that all living things change over time. These changes help the organism to live or reproduce better, or to adapt to its environment. Scientists have employed genetics, a new science to explain how evolution occurs. They also utilized the science of physics to calculate how much energy is needed to create such changes. Natural Selection To allow evolution to take place, organisms must be capable of reproducing and passing their genes to the next generation. This is a process known as natural selection, sometimes described as “survival of the fittest.” However the term “fittest” could be misleading since it implies that only the strongest or fastest organisms can survive and reproduce. The best-adapted organisms are the ones that adapt to the environment they reside in. Additionally, the environmental conditions can change rapidly and if a group is not well-adapted, it will be unable to survive, causing them to shrink or even extinct. The most important element of evolution is natural selection. This happens when phenotypic traits that are advantageous are more common in a population over time, resulting in the evolution of new species. This process is primarily driven by heritable genetic variations of organisms, which is a result of sexual reproduction. Selective agents can be any environmental force that favors or deters certain traits. These forces can be physical, like temperature, or biological, for instance predators. Over time, populations exposed to various selective agents could change in a way that they no longer breed with each other and are considered to be distinct species. Natural selection is a basic concept however it isn't always easy to grasp. Even among scientists and educators, there are many misconceptions about the process. Studies have revealed that students' knowledge levels of evolution are not associated with their level of acceptance of the theory (see the references). Brandon's definition of selection is confined to differential reproduction and does not include inheritance. However, several authors, including Havstad (2011) has suggested that a broad notion of selection that encompasses the entire cycle of Darwin's process is adequate to explain both adaptation and speciation. There are instances where an individual trait is increased in its proportion within a population, but not in the rate of reproduction. These instances may not be classified as natural selection in the focused sense of the term but could still meet the criteria for a mechanism like this to function, for instance the case where parents with a specific trait produce more offspring than parents without it. Genetic Variation Genetic variation refers to the differences between the sequences of the genes of members of a specific species. It is this variation that allows natural selection, which is one of the primary forces that drive evolution. Mutations or the normal process of DNA changing its structure during cell division could cause variations. Different gene variants may result in a variety of traits like eye colour fur type, colour of eyes, or the ability to adapt to changing environmental conditions. If a trait is beneficial, it will be more likely to be passed down to future generations. This is known as an advantage that is selective. A special type of heritable variation is phenotypic, which allows individuals to alter their appearance and behavior in response to the environment or stress. These changes can help them survive in a new habitat or to take advantage of an opportunity, for instance by increasing the length of their fur to protect against cold or changing color to blend with a specific surface. These phenotypic changes don't necessarily alter the genotype and therefore can't be considered to have contributed to evolution. Heritable variation enables adapting to changing environments. Natural selection can be triggered by heritable variations, since it increases the chance that people with traits that favor an environment will be replaced by those who aren't. However, in some instances, the rate at which a genetic variant is passed on to the next generation is not fast enough for natural selection to keep pace. Many harmful traits such as genetic diseases persist in populations despite their negative consequences. This is mainly due to a phenomenon called reduced penetrance. This means that some individuals with the disease-associated gene variant do not show any signs or symptoms of the condition. Other causes include gene-by-environment interactions and non-genetic influences like diet, lifestyle, and exposure to chemicals. To understand the reason why some undesirable traits are not removed by natural selection, it is essential to gain a better understanding of how genetic variation influences evolution. Recent studies have revealed that genome-wide association analyses which focus on common variations don't capture the whole picture of susceptibility to disease and that rare variants are responsible for a significant portion of heritability. Further studies using sequencing techniques are required to catalog rare variants across the globe and to determine their effects on health, including the influence of gene-by-environment interactions. Environmental Changes Natural selection influences evolution, the environment impacts species by changing the conditions in which they exist. The famous tale of the peppered moths is a good illustration of this. moths with white bodies, prevalent in urban areas where coal smoke blackened tree bark and made them easily snatched by predators while their darker-bodied counterparts thrived under these new conditions. However, the reverse is also true: environmental change could alter species' capacity to adapt to the changes they encounter. Human activities are causing environmental change at a global scale and the consequences of these changes are largely irreversible. These changes impact biodiversity globally and ecosystem functions. They also pose health risks to the human population especially in low-income nations due to the contamination of air, water and soil. As an example the increasing use of coal by countries in the developing world, such as India contributes to climate change, and increases levels of pollution in the air, which can threaten human life expectancy. The world's limited natural resources are being consumed at a higher rate by the population of humans. This increases the chance that many people are suffering from nutritional deficiencies and lack access to safe drinking water. The impact of human-driven changes in the environment on evolutionary outcomes is complex. Microevolutionary responses will likely alter the landscape of fitness for an organism. These changes may also alter the relationship between a particular trait and its environment. Nomoto et. and. showed, for example that environmental factors like climate, and competition can alter the phenotype of a plant and shift its selection away from its historical optimal suitability. It is important to understand how these changes are influencing the microevolutionary patterns of our time, and how we can use this information to determine the fate of natural populations in the Anthropocene. This is vital, since the environmental changes caused by humans will have a direct impact on conservation efforts as well as our health and well-being. This is why it is essential to continue to study the interactions between human-driven environmental changes and evolutionary processes at an international level. The Big Bang There are many theories about the Universe's creation and expansion. However, none of them is as well-known and accepted as the Big Bang theory, which has become a commonplace 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 large scale structure of the Universe. The Big Bang Theory is a simple explanation of how the universe began, 13.8 billions years ago as a huge and extremely hot cauldron. Since then, news has grown. The expansion has led to everything that exists today including the Earth and all its inhabitants. This theory is the most supported by a mix of evidence. This includes the fact that the universe appears flat to us; the kinetic energy and thermal energy of the particles that comprise it; the variations in temperature in the cosmic microwave background radiation; and the abundance of heavy and light elements that are found in the Universe. Furthermore the Big Bang theory also fits well with the data collected by telescopes and astronomical observatories as well as particle accelerators and high-energy states. In the early 20th century, scientists held a minority view on the Big Bang. Fred Hoyle publicly criticized it in 1949. However, after World War II, observational data began to come in that tipped the scales in favor of the Big Bang. In 1964, Arno Penzias and Robert Wilson serendipitously 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 the ionized radiation with an observable spectrum that is consistent with a blackbody at approximately 2.725 K was a major turning-point for the Big Bang Theory and tipped it in the direction of the prevailing Steady state model. The Big Bang is an important part of “The Big Bang Theory,” a popular TV show. Sheldon, Leonard, and the rest of the group use this theory in “The Big Bang Theory” to explain a variety of observations and phenomena. One example is their experiment which will explain how jam and peanut butter are mixed together.