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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 such as “What did T. rex taste like?” Charles Darwin's theory of natural selection explains how creatures who are better able to adapt biologically to changing environments over time, and those that don't end up becoming extinct. Science is about this process of evolution. What is Evolution? The word evolution has many nonscientific meanings, including “progress” or “descent with modification.” Scientifically it is a term used to describe a changing the characteristics of organisms (or species) over time. This change is based in biological terms on natural drift and selection. Evolution is one of the fundamental tenets of modern biology. It is an established theory that has withstood the tests of time and thousands of scientific tests. It does not address spiritual beliefs or God's presence, unlike many other theories in science, like the Copernican or germ theory of diseases. Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve in a step-like fashion over time. They called this the “Ladder of Nature” or the scala naturae. Charles Lyell used the term to describe this concept in his Principles of Geology, first published in 1833. In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It asserts that all species of organisms share common ancestors that can be traced using fossils and other evidence. This is the current perspective on evolution, which is supported by a variety of scientific fields that include molecular biology. Scientists aren't sure how organisms have evolved but they are sure that natural selection and genetic drift is the primary reason for the development of life. People with traits that are advantageous are more likely to live and reproduce, and they pass their genes on to the next generation. Over time the gene pool gradually changes and evolves into new species. Some scientists also employ the term”evolution” to refer to large-scale changes in evolutionary processes such as the creation of an entirely new species from an ancestral species. Certain scientists, including population geneticists, define evolution in a broad sense, referring to the net change in allele frequency over generations. Both definitions are accurate and acceptable, but some scientists believe that allele-frequency definitions omit important features of evolution. Origins of Life A key step in evolution is the emergence of life. The emergence of life occurs when living systems start to develop at a micro scale, for instance within individual cells. The origin of life is one of the major topics in various disciplines such as geology, chemistry, biology and chemistry. The question of how living things started is of particular importance in science because it is a major challenge to the theory of evolution. It is often described as “the mystery of life,” or “abiogenesis.” Traditionally, the notion that life can arise from nonliving things is known as spontaneous generation, or “spontaneous evolution.” This was a common belief before Louis Pasteur's research showed that it was impossible for the emergence of life to occur by the natural process. Many scientists believe it is possible to move from nonliving substances to living ones. However, the conditions needed are extremely difficult to replicate in the laboratory. This is why scientists studying the beginnings of life are also interested in determining the physical properties of the early Earth and other planets. Furthermore, the growth of life is dependent on the sequence of extremely complex chemical reactions that cannot be predicted from the fundamental physical laws on their own. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that perform some function, and the replication of these intricate molecules to create new DNA or RNA sequences. These chemical reactions are often compared to the chicken-and-egg dilemma of how life first appeared in the first place. The appearance of DNA/RNA and proteins-based cell machinery is vital to the birth of life, however, without the emergence of life, the chemical process that allows it isn't working. Abiogenesis research requires collaboration among researchers from different disciplines. This includes prebiotic scientists, astrobiologists and planetary scientists. Evolutionary Changes The word evolution is usually used to describe the accumulated changes in genetic characteristics of a population over time. These changes could be the result of adaptation to environmental pressures as explained in Darwinism. 에볼루션 바카라사이트 increases the frequency of genes that confer an advantage for survival in an animal, resulting in an overall change in the appearance of an entire group. These changes in evolutionary patterns are caused by mutations, reshuffling genes during sexual reproduction, and gene flow. While reshuffling and mutation of genes occur in all organisms The process through which beneficial mutations are more prevalent is known as natural selection. As noted above, individuals with the beneficial characteristic have a higher reproduction rate than those that do not. This differential in the number of offspring produced over many generations can cause a gradual change in the number of advantageous traits in a group. This is evident in the evolution of different beak shapes on finches from the Galapagos Islands. They have created these beaks to ensure that they can access food more easily in their new habitat. These changes in the shape and appearance of organisms can also aid in the creation of new species. The majority of changes are caused by one mutation, although sometimes multiple occur simultaneously. Most of these changes may be negative or even harmful however, a few could have a positive impact on the survival of the species and reproduce and increase their frequency as time passes. Natural selection is a process that causes the accumulating changes over time that lead to the creation of a new species. Many people mistakenly associate evolution with the concept of soft inheritance which is the notion that traits inherited from parents can be changed by conscious choice or by abuse. This is a misinterpretation of the biological processes that lead up to the process of evolution. It is more precise to say that evolution is a two-step independent process, which involves the forces of natural selection as well as mutation. Origins of Humans Humans of today (Homo sapiens) evolved from primates, a group of mammals that also includes chimpanzees, gorillas, and bonobos. The earliest human fossils show that our ancestors were bipeds, walkers with two legs. Genetic and biological similarities show that we have the same ancestry with Chimpanzees. In reality 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 dated between 8 and 6 million years old. In the course of time, humans have developed a variety of characteristics, including bipedalism and the use of fire. They also developed 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 emerged. These include a big brain that is complex and the capacity of humans to construct and use tools, and the diversity of our culture. Evolution occurs when genetic changes enable members of the group to better adapt to the environment. This adaptation is driven by natural selection, a process whereby certain traits are more desirable than other traits. The ones who are better adapted are more likely to pass on their genes to the next generation. This is how all species evolve and is the foundation for the theory of evolution. Scientists refer to this as the “law of natural selection.” The law states that species which have a common ancestor, tend to develop similar characteristics over time. This is because those traits make it easier for them to survive and reproduce in their environment. Every organism has an molecule called DNA that holds the information needed to control their growth. The DNA molecule is composed of base pairs that are arranged in a spiral around sugar molecules and phosphate molecules. The sequence of bases within each string determines the phenotype or the distinctive appearance and behavior of a person. Variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles). Fossils from the earliest human species Homo erectus, as well as Homo neanderthalensis have been found in Africa, Asia and Europe. While there are some differences between them, these fossils all support the hypothesis that modern humans first appeared in Africa. The fossil evidence and genetic evidence suggest that early humans migrated from Africa into Asia and then Europe.