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The Berkeley Evolution Site The Berkeley site contains resources that can assist students and teachers understand and teach evolution. The materials are arranged in optional learning paths for example “What does T. rex look like?” Charles Darwin's theory on natural selection explains how animals that are better equipped to adapt biologically to a changing environments survive longer and those that don't disappear. This process of evolution is what science is all about. What is Evolution? The word evolution can be used to refer to a variety of nonscientific meanings. For example it could mean “progress” and “descent with modifications.” Scientifically, it refers to a changes in the traits of living things (or species) over time. In terms of biology, this change is based on natural selection and genetic drift. Evolution is an important principle in modern biology. It is a theory that has been confirmed by a myriad of scientific tests. It does not address the existence of God or religious beliefs like other scientific theories such as the Copernican or germ theory of diseases. Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a stepped-like manner over time. They referred to this as the “Ladder of Nature” or the scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology. Darwin revealed his theory of evolution in his book On the Origin of Species, written in the early 1800s. It states that all species of organisms share an ancestry that can be traced through fossils and other evidence. This is the current view of evolution, and is supported by numerous research lines in science, including molecular genetics. While 에볼루션게이밍 do not know the exact mechanism by which organisms evolved, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. People with traits that are advantageous are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. Over time the gene pool gradually changes and evolves into new species. Some scientists employ the term evolution in reference to large-scale changes, like the formation of a species from an ancestral one. Other scientists, such as population geneticists, define the term “evolution” more broadly by referring an overall change in the frequency of alleles across generations. Both definitions are accurate and acceptable, but certain scientists argue that allele frequency definitions do not include important aspects of evolutionary process. Origins of Life One of the most crucial steps in evolution is the emergence of life. The beginning of life takes place when living systems begin to develop at a micro scale, for instance within cells. The origins of life is one of the major topics in various disciplines that include geology, chemistry, biology and chemistry. The nature of life is a topic of interest in science, as it challenges the theory of evolution. It is often referred to as “the mystery of life” or “abiogenesis.” The idea that life could emerge from non-living objects was referred to as “spontaneous generation” or “spontaneous evolutionary”. 에볼루션게이밍 was a popular belief prior to Louis Pasteur's tests showed that the creation of living organisms was not possible through a natural process. Many scientists still think it is possible to move from living to nonliving substances. However, the conditions needed are extremely difficult to reproduce in labs. Researchers who are interested in the evolution and origins of life are also eager to understand the physical properties of the early Earth as well as other planets. The life-cycle of a living organism is dependent on a variety of complex chemical reactions, which are not predicted by simple physical laws. These include the transformation of long information-rich molecules (DNA or RNA) into proteins that perform some function as well as the replication of these intricate molecules to generate new DNA or sequences of RNA. These chemical reactions can be compared with the chicken-and-egg issue that is the emergence and growth of DNA/RNA, protein-based cell machinery, is necessary to begin the process of becoming a living organism. Although without life, the chemistry required to make it possible is working. Research in the area of abiogenesis requires collaboration among scientists from a variety of fields. This includes prebiotic chemists, astrobiologists, planetary scientists, geologists and geophysicists. Evolutionary Changes The term “evolution” is commonly used today to refer to the accumulated changes in genetic characteristics of a population over time. These changes can result from adaptation to environmental pressures, as explained in the article on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection. The latter is a mechanism that increases the frequency of genes which confer an advantage in survival over other species, resulting in gradual changes in the overall appearance of a population. The specific mechanisms behind these changes in evolutionary process include mutation and reshuffling of genes in sexual reproduction, as well as gene flow between populations. While reshuffling and mutation of genes occur in all living things and the process by which beneficial mutations are more frequent is called natural selection. As previously mentioned, those who have the advantageous trait have a higher reproduction rate than those that do not. Over the course of several generations, this differential in the number of offspring born can result in gradual changes in the average amount of desirable traits in a population. A good example of this is the increase in beak size on different species of finches in the Galapagos Islands, which have developed beaks with different shapes to allow them to more easily access food in their new habitat. These changes in the form and shape of living organisms may also help create new species. The majority of changes are caused by one mutation, although sometimes multiple occur simultaneously. The majority of these changes are neutral or even detrimental to the organism, but a small percentage can have an advantageous impact on the survival of the organism and its reproduction, thereby increasing the frequency of these changes in the population over time. This is the way of natural selection, and it could eventually result in the gradual changes that eventually lead to an entirely new species. Some people confuse the notion of evolution with the notion that traits inherited can be changed through conscious choice or use and abuse, a notion called soft inheritance. This is a misinterpretation of the nature of evolution, and of the actual biological processes that trigger it. A more precise description is that evolution involves a two-step process, which involves the separate, and often competing, forces of natural selection and mutation. Origins of Humans Modern humans (Homo sapiens) evolved from primates, a group of mammals that includes chimpanzees, gorillas, and bonobos. Our ancestors walked on two legs, as demonstrated by the earliest fossils. Biological and genetic similarities indicate that we share the same ancestry with the chimpanzees. In actual fact we are the closest with chimpanzees in the Pan Genus that includes pygmy and pygmy chimpanzees and bonobos. The last common ancestor between humans and chimpanzees was 8 to 6 million years old. Humans have developed a range of traits throughout time such as bipedalism, use of fire, and the development of advanced tools. It's only in the last 100,000 years that we've developed the majority of our important characteristics. These include a large brain that is sophisticated and the capacity of humans to construct and use tools, as well as the diversity of our culture. Evolution is when genetic changes allow members of the group to better adapt to their environment. Natural selection is the process that drives this change. Certain traits are preferred over others. The ones with the best adaptations are more likely to pass their genes to the next generation. This is the way that all species evolve and is the basis of the theory of evolution. Scientists refer to it as the “law of Natural Selection.” The law says that species that share a common ancestor tend to develop similar characteristics over time. This is because these traits make it easier to survive and reproduce within their environment. Every living thing has a DNA molecule that contains the information necessary to direct their growth. The structure of DNA is made of base pairs that are arranged in a spiral around phosphate and sugar molecules. The sequence of bases in each strand determines the phenotype, the characteristic appearance and behavior of a person. Variations in changes and reshuffling of genetic material (known as alleles) during sexual reproduction can cause variation in a population. Fossils of the earliest human species, Homo erectus and Homo neanderthalensis were discovered in Africa, Asia, and Europe. Although there are some differences they all support the idea that modern humans first appeared in Africa. The evidence from fossils and genetics suggests that early humans left Africa and moved to Asia and Europe.