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The Berkeley Evolution Site Students and teachers who explore the Berkeley site will find resources to aid in understanding and teaching evolution. The materials 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 that are better equipped to adapt biologically to changing environment survive over time and those that do not disappear. Science is about this process of evolution. What is Evolution? The term “evolution” has a variety of nonscientific meanings. For instance “progress” or “descent with modification.” Scientifically it refers to a process of change in the characteristics of living 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 a well-supported theory that has stood the test of time and thousands of scientific experiments. In contrast to other theories in science, such as the Copernican theory or the germ theory of disease, the evolution theory is not a discussion of spiritual belief or the existence of God. 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 idea in his Principles of Geology, first published in 1833. Darwin published his theory of evolution in his book On the Origin of Species published in the early 1800s. It asserts that all species of organisms share common ancestors that can be traced through fossils and other evidence. 에볼루션 슬롯게임 is the modern view of evolution, and is supported by numerous lines of scientific research which includes molecular genetics. Scientists don't know the evolution of organisms but they are sure that natural selection and genetic drift is the reason for the development of life. People with desirable traits are more likely to survive and reproduce, and they pass their genes on to the next generation. In time this leads to a gradual accumulation of changes in the gene pool that gradually create new species and forms. Certain scientists also use the term evolution to refer to large-scale evolutionary changes like the creation of a new species from an ancestral species. Other scientists, such as population geneticists, define the term “evolution” more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are correct and acceptable, but certain scientists argue that allele frequency definitions do not include important aspects of evolutionary process. Origins of Life The most important step in evolution is the appearance of life. This occurs when living systems begin to evolve at the micro level, within cells, for example. The origins of life is one of the major topics in various disciplines, including biology, chemistry and geology. The origin of life is a topic of interest in science, as it challenges the theory of evolution. It is sometimes referred to as “the mystery” of life or “abiogenesis.” The idea that life could arise from non-living matter was known as “spontaneous generation” or “spontaneous evolutionary”. It was a common belief prior to Louis Pasteur's tests showed that the emergence of living organisms was not possible through an organic process. Many scientists believe it is possible to go from nonliving substances to living ones. However, the conditions required are extremely difficult to reproduce in a laboratory. This is why researchers studying the origins of life are also keen to understand the physical properties of early Earth and other planets. In addition, the development of life depends on an intricate sequence of chemical reactions that cannot be predicted from basic physical laws alone. This includes the conversion 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 sequences of RNA. These chemical reactions are often compared to the chicken-and-egg dilemma of how life first appeared in the first place. The development of DNA/RNA as well as proteins-based cell machinery is vital for the onset of life, but without the emergence of life the chemistry that makes it possible isn't working. Abiogenesis research requires collaboration between scientists from various disciplines. This includes prebiotic chemists astrobiologists, planetary scientists, geologists and geophysicists. Evolutionary Changes The word evolution is usually used today to describe the accumulated changes in the genetic characteristics of populations over time. These changes may 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 those genes in a species that offer an advantage in survival over others, resulting in gradual changes in the overall appearance of a population. The specific mechanisms that cause these evolutionary changes are mutation or reshuffling genes during sexual reproduction, and also gene flow between populations. While reshuffling and mutations of genes happen in all organisms The process through which beneficial mutations are more prevalent is called natural selection. This happens because, as noted above, those individuals with the beneficial trait tend to have a higher reproduction rate than those with it. This difference in the number of offspring born over many generations can result in a gradual change in the number of advantageous characteristics in the group. This is evident in the evolution of various beak designs on finches that are found in the Galapagos Islands. They have developed these beaks in order that they can access food more quickly in their new home. These changes in form and shape can also help create new organisms. The majority of the changes that occur are caused by one mutation, however occasionally, multiple mutations occur at the same time. The majority of these changes could be harmful or neutral however, a few can have a beneficial impact on survival and reproduce, increasing their frequency as time passes. This is the way of natural selection, and it could be a time-consuming process that produces the cumulative changes that eventually result in the creation of a new species. Many people confuse evolution with the idea of soft inheritance, which is the idea that inherited traits can be changed through deliberate choice or misuse. This is a misunderstanding of the nature of evolution and of the actual biological processes that cause it. It is more accurate to say that the process of evolution is a two-step, separate process, that is influenced by the forces of natural selection and mutation. Origins of Humans Modern humans (Homo sapiens) evolved from primates – a group of mammals that also includes chimpanzees, gorillas, and bonobos. Our ancestors walked on two legs, as evidenced by the first fossils. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In fact we are the closest with chimpanzees in the Pan Genus which includes bonobos and pygmy chimpanzees. The last common ancestor between humans and chimpanzees was between 8 and 6 million years old. Humans have evolved a variety of traits over time such as bipedalism, use of fire and advanced tools. It is only within the last 100,000 years that we have developed the majority of our key characteristics. These include language, a large brain, the ability to create and utilize sophisticated tools, and a the diversity of our culture. Evolution occurs when genetic changes enable members of a group to better adapt to the environment. This adaptation is triggered by natural selection, a process that determines certain traits are preferred over others. People with better adaptations are more likely to pass their genes to the next generation. This is the way all species evolve, and the foundation for the theory of evolution. Scientists refer to this 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 those traits make it easier for them to live and reproduce in their natural environment. All organisms have a DNA molecule that is the source of information that helps direct their growth and development. The DNA molecule consists of base pairs that are arranged in a spiral around sugar molecules and phosphate molecules. The sequence of bases found in each string determines the phenotype or the characteristic appearance and behavior of a person. Different mutations and reshufflings of the genetic material (known as alleles) during reproduction causes variation in a group. Fossils of the earliest human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. These fossils, despite variations in their appearance, all support the theory of the origins of modern humans in Africa. Evidence from fossils and genetics suggest that early humans migrated out of Africa into Asia and then Europe.