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The Berkeley Evolution Site The Berkeley site offers resources that can help students and educators to understand and teach about evolution. The resources are organized into a variety of learning paths, such as “What did T. rex taste like?” Charles Darwin's theory of natural selection explains how animals who are better able to adapt to changes in their environments survive longer and those who do not end up becoming extinct. This process of evolution is what science is all about. What is Evolution? The term “evolution” has a variety of nonscientific meanings, such as “progress” or “descent with modification.” Scientifically, it refers to a process of changes in the traits of living organisms (or species) over time. 에볼루션 무료체험 for this change is biological terms on natural selection and drift. Evolution is the central tenet of modern biology. It is a theory that has been tested and verified by a myriad of scientific tests. Contrary to other theories of science, such as the Copernican theory or the germ theory of disease, the evolution theory 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 traits were predetermined to change in a stepped-like manner over time. They called this the “Ladder of Nature” or scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology. In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It states that all species of organisms have the same ancestry, which can be proven through fossils and other lines of evidence. This is the current understanding of evolution, which is supported by numerous lines of research in science which includes molecular genetics. Scientists aren't sure how organisms evolved however they are certain that natural selection and genetic drift is the primary reason for the evolution of life. People with desirable traits are more likely than others to survive and reproduce. These individuals transmit their genes on to the next generation. In time, this results in an accumulation of changes to the gene pool, which eventually result in new species and forms. Some scientists also employ the term evolution to describe large-scale evolutionary changes like the creation of the new species from an ancestral species. Certain scientists, including population geneticists, define the term “evolution” in a broad sense, talking about the net variation in the frequency of alleles over generations. Both definitions are valid and reliable however some scientists believe that the allele-frequency definition omits crucial aspects of the evolutionary process. Origins of Life The most important step in evolution is the emergence of life. This occurs when living systems begin to develop at the micro level – within individual cells, for example. The origins of life are an important subject in a variety of areas such as biology and chemical. The question of how living things got their start is a major topic in science because it is an important challenge to the theory of evolution. It is often called “the mystery of life” or “abiogenesis.” The idea that life could arise from non-living objects was referred to as “spontaneous generation” or “spontaneous evolutionary”. This was a popular belief before Louis Pasteur's tests proved that the creation of living organisms was not possible through a natural process. Many scientists believe it is possible to transition from living to nonliving substances. However, the conditions required are extremely difficult to reproduce in labs. This is why researchers investigating the beginnings of life are also interested in determining the physical properties of the early Earth and other planets. Additionally, the evolution of life is a sequence of very complex chemical reactions that cannot be predicted based on basic physical laws alone. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that carry out a function, and the replication of these intricate molecules to generate new DNA or sequences of RNA. These chemical reactions can be compared to the chicken-and-egg problem: the emergence and development of DNA/RNA, protein-based cell machinery, is necessary for the onset life. Although, without life, the chemistry required to create it appears to be working. Abiogenesis research requires collaboration with researchers from different disciplines. This includes prebiotic scientists, astrobiologists, and planet scientists. Evolutionary Changes The word evolution is usually used to refer to the accumulated changes in the genetic traits of a population over time. These changes can be the result of adaptation to environmental pressures as explained in Darwinism. This mechanism also increases the frequency of genes that provide the advantage of survival for the species, leading to an overall change in the appearance of a group. These evolutionary changes are caused by mutations, reshuffling genes during sexual reproduction and gene flow. Natural selection is the process that makes beneficial mutations more common. All organisms undergo changes and reshuffles in their genes. This happens because, as we've mentioned earlier, those individuals with the beneficial trait tend to have a higher reproductive rate than those who do not have it. This differential in the number of offspring born over a number of generations could result in a gradual change in the number of advantageous traits within a group. This can be seen in the evolution of various beak shapes for finches from the Galapagos Islands. They have created these beaks to ensure that they can access food more easily in their new environment. These changes in form and shape can also aid in the creation of new species. The majority of changes are caused by one mutation, although sometimes multiple occur at once. Most of these changes are neutral or even detrimental to the organism, but a small percentage can have a positive impact on the longevity and reproduction of the species, thus increasing the frequency of these changes in the population over time. This is the mechanism of natural selection, and it could be a time-consuming process that produces the accumulating changes that eventually result in the creation of a new species. Many people confuse the concept of evolution with the idea that the traits inherited from parents can be altered by conscious choice or by use and abuse, a notion known as soft inheritance. This is a misunderstanding of the biological processes that lead up to the process of evolution. A more accurate description is that evolution is a two-step procedure involving the independent, and often competing, forces of natural selection and mutation. Origins of Humans Humans of today (Homo sapiens) evolved from primates – a group of mammals that includes gorillas, chimpanzees, and bonobos. The earliest human fossils prove that our ancestors were bipeds. They were walkers with two legs. Genetic and biological similarities show that we share the same ancestry with Chimpanzees. In actual fact we are the most closely related to the chimpanzees within the Pan genus that includes pygmy and bonobos and pygmy chimpanzees. The last common ancestor of modern humans and chimpanzees was between 8 and 6 million years ago. Humans have evolved a wide range of characteristics over time such as bipedalism, use of fire and advanced tools. However, it is only in the past 100,000 years or so that the majority of the important traits that distinguish us from other species have been developed. These include language, a large brain, the ability to construct and use complex tools, and the diversity of our culture. The process of evolution occurs when genetic changes allow members of a population to better adapt to their surroundings. Natural selection is the mechanism that triggers this adaptation. Certain characteristics are more desirable than others. People with better adaptations are more likely to pass on their genes to the next generation. This is the way all species evolve and the foundation for the theory of evolution. Scientists refer to it as the “law of natural selection.” The law states species that have an ancestor in common will tend to acquire similar traits as time passes. This is because these traits make it easier to live and reproduce in their environment. Every organism has the DNA molecule, which contains the information needed to guide 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. The variations in a population are caused by mutations and reshufflings of genetic material (known collectively as alleles). Fossils from the earliest human species Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite some differences in their appearance all support the idea of the origins of modern humans in Africa. The fossil evidence and genetic evidence suggest that early humans came out of Africa into Asia and then Europe.