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The Berkeley Evolution Site The Berkeley site offers resources that can help students and teachers to understand and teach about evolution. The materials are arranged into different learning paths like “What did T. rex taste like?” Charles Darwin's theory of natural selection explains how creatures who are better equipped to adapt biologically to changing environment survive over time and those that don't become extinct. Science is concerned with this process of biological evolutionary change. What is Evolution? The word evolution can be used to refer to a variety of nonscientific meanings. For instance it could refer to “progress” and “descent with modifications.” It is an academic term that is used to describe the process of changing characteristics in a species or species. This change is based in biological terms on natural drift and selection. Evolution is a key principle in the field of biology today. It is a well-supported theory that has withstood the tests of time and thousands of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, the evolution theory does not address issues of spiritual belief or God's existence. Early evolutionists, such as 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. This was called the “Ladder of Nature” or 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 claims that different species of organisms share a common ancestry, which can be traced through fossils and other lines of evidence. This is the current perspective of evolution, which is supported by a variety of areas of science that include molecular biology. While scientists do not know exactly how organisms evolved, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. People with advantages are more likely to survive and reproduce. These individuals then pass their genes on to the next generation. As time passes, this results in gradual changes to the gene pool which gradually result in new species and forms. 에볼루션 바카라 무료체험 employ the term”evolution” to refer to large-scale changes, such the evolution of a species from an ancestral one. Other scientists, like population geneticists, define evolution more broadly by referring an overall variation in the frequency of alleles over generations. Both definitions are correct and acceptable, however some scientists argue that allele-frequency definitions miss important aspects of the evolutionary process. Origins of Life The emergence of life is a key step in the process of evolution. The emergence of life occurs when living systems begin to develop at a micro scale, for instance within cells. The origins of life are an important issue in a variety of fields that include biology and the field of chemistry. The nature of life is a subject of interest in science because it is a challenge to 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”. This was a popular belief before Louis Pasteur's experiments proved that the emergence of living organisms was not possible by the natural process. Many scientists still believe it is possible to make the transition from nonliving substances to life. The conditions necessary to create life are difficult to reproduce in a lab. Researchers interested in the origins and development of life are also keen to learn about the physical characteristics of the early Earth as well as other planets. In addition, the development of life is a sequence of very complex chemical reactions that can't be predicted from basic physical laws on their own. These include the reading and re-reading of complex molecules, like DNA or RNA, to create proteins that serve a specific function. These chemical reactions can be compared with the chicken-and-egg issue that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is required for the onset life. Although without life, the chemistry that is required to enable it does appear to work. Research in the area of abiogenesis requires collaboration among scientists from a variety of fields. This includes prebiotic scientists, astrobiologists and planet scientists. Evolutionary Changes Today, the word evolution is used to describe cumulative changes in genetic characteristics over time. These changes could result from the response to environmental pressures as explained in the article on Darwinism (see the entry on Charles Darwin for background) or natural selection. This is a process that increases the frequency of genes that offer a survival advantage over others, resulting in an ongoing change in the overall appearance of a particular population. The specific mechanisms responsible for these evolutionary changes include mutation, reshuffling of genes during sexual reproduction, and also gene flow between populations. While mutation and reshuffling of genes happen in all organisms and the process by which beneficial mutations become more common is called natural selection. As mentioned above, those who possess the desirable trait have a higher reproductive rate than those who don't. This difference in the number of offspring that are produced over many generations can result in a gradual change in the average number of beneficial traits within a group. A good example of this is the growth of beak size on various species of finches found on the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new home. These changes in the shape and form of organisms could also aid in the creation of new species. The majority of changes are caused by a single mutation, although sometimes multiple occur at once. The majority of these changes are neutral or even harmful to the organism however a small portion of them could have an advantageous impact on survival and reproduction, thus increasing the frequency of these changes in the population over time. This is the mechanism of natural selection, and it is able to eventually result in the gradual changes that eventually lead to an entirely new species. Some people think that evolution is a form of soft inheritance which is the notion that inherited traits can be changed through deliberate choice or misuse. This is a misunderstanding of the biological processes that lead to evolution. A more precise description is that evolution is a two-step process involving the independent, and often competing, forces of natural selection and mutation. Origins of Humans Modern humans (Homo Sapiens) evolved from primates, a species of mammal species which includes gorillas and chimpanzees. The earliest human fossils indicate that our ancestors were bipeds – walkers on two legs. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In reality, we are most closely connected to chimpanzees belonging to the Pan genus, which includes bonobos and pygmy chimpanzees. The last common ancestor between modern humans and chimpanzees dated 8 to 6 million years old. Humans have developed a range of traits throughout time, including bipedalism, the use of fire, and the development of advanced tools. But it's only in the last 100,000 years or so that most of the essential traits that distinguish us from other species have been developed. These include a big brain that is complex human ability to create and use tools, and cultural variety. Evolution happens when genetic changes allow members of a population to better adapt to their environment. This adaptation is triggered by natural selection, a process that determines certain traits are more desirable than others. The more adapted are more likely to pass on their genes to the next generation. This is how all species evolve, and 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 traits over time. This is because these traits make it easier to survive and reproduce within their environment. All organisms possess a DNA molecule that contains the information needed to guide their growth. The DNA structure is composed of base pairs that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. A variety of mutations and reshufflings of the genetic material (known as alleles) during reproduction causes variation in a population. Fossils from the early human species Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite differences in their appearance, all support the hypothesis of the origins of modern humans in Africa. The fossil and genetic evidence suggests that the first humans left Africa and moved to Asia and Europe.