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How Evolution Site Influenced My Life For The Better The Berkeley Evolution Site Students and teachers who explore the Berkeley site will find a wealth of resources to help them understand and teach evolution. The resources are organized into different learning paths, such as "What does T. rex look like?" Charles Darwin's theory of natural selection states that over time, animals that are more adaptable to changing environments thrive, and those that do not become extinct. Science is all about this process of evolution. What is Evolution? The term "evolution" can be used to refer to a variety of nonscientific meanings. For example it could refer to "progress" and "descent with modifications." It is scientifically based and refers to the process of changing characteristics in a species or species. In 에볼루션 코리아 , this change is based on natural selection and genetic drift. Evolution is one of the fundamental tenets of modern biology. It is a theory that has been tested and verified by a myriad of scientific tests. Unlike many other scientific theories such as the Copernican theory or the germ theory of disease, evolution is not a discussion of religious belief or God's existence. Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve in a gradual manner over time. They called this the "Ladder of Nature" or scala naturae. Charles Lyell used the term to describe this concept in his Principles of Geology, first published in 1833. Darwin presented his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It asserts that all species of organisms share common ancestors that can be traced by fossils and other evidence. This is the current perspective of evolution, which is supported by a variety of areas of science which include molecular biology. Although scientists aren't able to determine exactly how organisms developed however they are sure that the evolution of life on earth is the result of natural selection and genetic drift. Individuals with advantageous characteristics are more likely to live and reproduce. They transmit their genes to the next generation. In time this leads to gradual changes in the gene pool, which eventually create new species and types. Some scientists also use the term evolution to describe large-scale evolutionary changes such as the creation of the new species from an ancestral species. Other scientists, like population geneticists, define it more broadly by referring an overall change in allele frequencies over generations. Both definitions are acceptable and precise, although some scientists argue that the allele-frequency definition omits essential aspects of the evolution process. Origins of Life One of the most crucial steps in evolution is the appearance of life. The emergence of life happens when living systems start to evolve at a micro scale, for instance within cells. The origins of life is one of the major topics in various disciplines that include biology, chemistry, and geology. The question of how living organisms began has a special place in science because it is an important challenge to the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis." Traditionally, the idea that life can emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a popular view before Louis Pasteur's research showed that it was impossible for the emergence of life to happen through an entirely natural process. Many scientists still think it is possible to go from living to nonliving substances. However, the conditions that are required are extremely difficult to replicate in a laboratory. Researchers interested in the origins and development of life are also eager to understand the physical properties of the early Earth as well as other planets. In addition, the development of life depends on the sequence of extremely complex chemical reactions that can't be predicted from basic physical laws alone. This includes the conversion of long information-rich molecules (DNA or RNA) into proteins that carry out functions, and the replication of these intricate molecules to create new DNA or RNA sequences. These chemical reactions can be compared to the chicken-and-egg issue: the emergence and development of DNA/RNA, a protein-based cell machinery, is required for the beginning of life. However, without life, the chemistry required to enable it does appear to work. Abiogenesis research requires collaboration among researchers from different disciplines. This includes prebiotic chemists, the astrobiologists, the planet scientists geophysicists and geologists. Evolutionary Changes The term "evolution" is used to describe general changes in genetic traits over time. These changes can result from adaptation to environmental pressures, as described in the entry on Darwinism (see the entry on Charles Darwin for background) or natural selection. This is a method that increases the frequency of genes that offer an advantage in survival over others, resulting in an ongoing change in the appearance of a particular population. The specific mechanisms behind these evolutionary changes are mutation, reshuffling of genes during sexual reproduction, and also gene flow between populations. While reshuffling and mutations of genes happen in all organisms, the process by which beneficial mutations become more common is called natural selection. This happens because, as we've mentioned earlier those who have the advantageous trait are likely to have a higher reproduction rate than those with it. Over the course of several generations, this differential in the numbers of offspring born could result in gradual changes in the number of advantageous characteristics in a particular population. An excellent example is the growth of beak size on different species of finches on the Galapagos Islands, which have developed beaks with different shapes to allow them to more easily access food in their new environment. These changes in the shape and form of living organisms may also help create new species. The majority of the changes that take place are caused by one mutation, but occasionally, multiple mutations occur simultaneously. Most of these changes may be neutral or even harmful however, a few may have a positive effect on survival and reproduction and increase their frequency as time passes. This is the way of natural selection and it could be a time-consuming process that produces the accumulating changes that ultimately lead to an entirely new species. Many people mistakenly associate evolution with the concept of soft inheritance, which is the idea that inherited traits can be altered by deliberate choice or misuse. This is a misunderstanding of the nature of evolution, and of the actual biological processes that lead to it. It is more accurate to say that evolution is a two-step, separate process, which involves the forces of natural selection as well as mutation. Origins of Humans Modern humans (Homo sapiens) evolved from primates - a species of mammals that includes gorillas, chimpanzees, and bonobos. Our ancestors walked on two legs, as demonstrated by the first fossils. Genetic and biological similarities show that we share an intimate relationship with Chimpanzees. In reality our closest relatives are the chimpanzees from the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor as well as chimpanzees lived between 8 and 6 million years ago. Humans have evolved a variety of traits over time such as bipedalism, use of fire, and the development of advanced tools. It is only in the last 100,000 years or so that the majority of the essential traits that distinguish us from other species have developed. These include a large, complex brain human ability to build and use tools, as well as the diversity of our culture. The process of evolution occurs when genetic changes allow members of a population to better adapt to their environment. Natural selection is the process that drives this change. Certain traits are preferred over others. The more adapted are more likely to pass their genes on to the next generation. This is the way all species evolve and the foundation for the theory of evolution. Scientists call this the "law of natural selection." The law states that species which have a common ancestor are more likely to develop similar traits over time. This is because these traits make it easier to reproduce and survive within their environment. Every living thing has an molecule called DNA that holds the information necessary to direct their growth. The DNA molecule is made up of base pairs that are arranged in a spiral around sugar molecules and phosphate molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. Different mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction cause variation in a population. Fossils of the first human species, Homo erectus and Homo neanderthalensis were discovered in Africa, Asia, and Europe. Although there are some differences they all support the hypothesis that modern humans first appeared in Africa. Evidence from fossils and genetics suggest that early humans migrated out of Africa into Asia and then Europe.
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