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Evolution Explained The most basic concept is that living things change in time These changes can help the organism survive or reproduce better or to adapt to its environment Scientists have employed genetics a science that is new to explain how evolution occurs They also have used physics to calculate the amount of energy needed to trigger these changes Natural Selection To allow evolution to take place in a healthy way organisms must be capable of reproducing and passing their genes to the next generation This is the process of natural selection sometimes described as survival of the most fittest However the term fittest could be misleading because it implies that only the most powerful or fastest organisms will survive and reproduce The most adaptable organisms are ones that adapt to the environment they live in Environmental conditions can change rapidly and if the population isnt welladapted to the environment it will not be able to endure which could result in an increasing population or becoming extinct The most important element of evolutionary change is natural selection This occurs when phenotypic traits that are advantageous are more common in a given population over time leading to the development of new species This is triggered by the genetic variation that is heritable of organisms that result from sexual reproduction and mutation as well as the need to compete for scarce resources Selective agents may refer to any element in the environment that favors or discourages certain characteristics These forces can be biological like predators or physical like temperature 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 however it can be difficult to comprehend Misconceptions regarding the process are prevalent even among scientists and educators Surveys have revealed that there is a small relationship between students knowledge of evolution and their acceptance of the theory Brandons definition of selection is restricted to differential reproduction and does not include inheritance Havstad 2011 is one of many authors who have argued for a more broad concept of selection which captures Darwins entire process This could explain the evolution of species and adaptation There are also cases where an individual trait is increased in its proportion within an entire population but not in the rate of reproduction These cases may not be considered natural selection in the strict sense of the term but could still be in line with Lewontins requirements for a mechanism to work such as when parents who have a certain trait have more offspring than parents without it Genetic Variation Genetic variation is the difference between the sequences of genes of the members of a specific species Natural selection is one of the main forces behind evolution Variation can occur due to mutations or the normal process by the way DNA is rearranged during cell division genetic recombination Different gene variants may result in different traits such as eye colour fur type or the capacity to adapt to adverse environmental conditions If a trait is beneficial it will be more likely to be passed down to the next generation This is referred to as an advantage that is selective A special type of heritable change is phenotypic plasticity It allows individuals to alter their appearance and behavior in response to the environment or stress Such changes may enable them to be more resilient in a new habitat or take advantage of an opportunity for instance by growing longer fur to guard against the cold or changing color to blend in with a specific surface These phenotypic changes do not necessarily affect the genotype and thus cannot be considered to have caused evolutionary change Heritable variation is vital to evolution since it allows for adaptation to changing environments Natural selection can be triggered by heritable variation as it increases the chance that those with traits that are favorable to the particular environment will replace those who do not However in certain instances the rate at which a genetic variant is transferred to the next generation is not fast enough for natural selection to keep up Many negative traits like genetic diseases remain in the population despite being harmful This is due to a phenomenon known as diminished penetrance It means that some people with the diseaseassociated variant of the gene dont show symptoms or symptoms of the condition Other causes include gene by interactions with the environment and other factors like lifestyle eating habits diet and exposure to chemicals To understand the reason why some harmful traits do not get removed by natural selection it is essential to gain an understanding of how genetic variation influences the evolution Recent studies have shown that genomewide association studies that focus on common variations do not reveal the full picture of susceptibility to disease and that a significant portion of heritability can be explained by rare variants Get Source is imperative to conduct additional sequencingbased studies to document rare variations across populations worldwide and assess their impact including genebyenvironment interaction Environmental Changes The environment can affect species by changing their conditions The famous tale of the peppered moths illustrates this concept the whitebodied moths abundant in urban areas where coal smoke blackened tree bark were easy targets for predators while their darkerbodied counterparts thrived under these new conditions But the reverse is also true environmental change could alter species capacity to adapt to the changes they face Human activities have caused global environmental changes and their effects are irreversible These changes affect biodiversity and ecosystem functions They also pose health risks to humanity especially in lowincome countries because of the contamination of water air and soil For instance an example the growing use of coal by developing countries like India contributes to climate change and also increases the amount of pollution of the air which could affect the life expectancy of humans Moreover human populations are using up the worlds finite resources at a rapid rate This increases the risk that a large number of people will suffer from nutritional deficiencies and lack access to safe drinking water The impact of humandriven environmental changes on evolutionary outcomes is a complex matter with microevolutionary responses to these changes likely to alter the fitness landscape of an organism These changes can also alter the relationship between a particular trait and its environment For instance a research by Nomoto and co involving transplant experiments along an altitudinal gradient demonstrated that changes in environmental cues such as climate and competition can alter the phenotype of a plant and shift its directional choice away from its previous optimal fit It is therefore important to understand the way these changes affect the current microevolutionary processes and how this data can be used to determine the fate of natural populations in the Anthropocene era This is crucial as the changes in the environment triggered by humans have direct implications for conservation efforts and also for our individual health and survival It is therefore essential to continue the research on the relationship between humandriven environmental changes and evolutionary processes at an international scale The Big Bang There are a variety of theories regarding 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 is able to explain a broad range of observed phenomena including the number of light elements the cosmic microwave background radiation and the largescale structure of the Universe The Big Bang Theory is a simple explanation of how the universe began 138 billions years ago as a huge and extremely hot cauldron Since then it has grown The expansion has led to all that is now in existence including the Earth and all its inhabitants The Big Bang theory is supported by a myriad of evidence These include the fact that we see the universe as flat as well as the kinetic and thermal energy of its particles the variations in temperature of the cosmic microwave background radiation and the densities and abundances of heavy and lighter elements in the Universe Additionally the Big Bang theory also fits well with the data gathered by astronomical observatories and telescopes as well as particle accelerators and highenergy states In the beginning of the 20th century the Big Bang was a minority opinion among scientists In 1949 astronomer Fred Hoyle publicly dismissed it as a fanciful nonsense However after World War II observational data began to come in that tilted the scales in favor of the Big Bang In 1964 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 the ionized radiation with an apparent spectrum that is in line with a blackbody at about 2725 K was a major turningpoint for the Big Bang Theory and tipped it in its favor against the prevailing Steady state model The Big Bang is a integral part of the popular television show The Big Bang Theory In the program Sheldon and Leonard employ this theory to explain various phenomena and observations including their experiment on how peanut butter and jelly are mixed together
