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The Berkeley Evolution Site The Berkeley site offers resources that can assist students and teachers to understand and teach about evolution. The materials are organized in optional learning paths, such as “What does T. rex look like?” Charles Darwin's theory of natural selection explains how over time creatures that are more able to adapt to changing environments survive and those that are not extinct. This process of evolution is the main focus of science. What is Evolution? The term “evolution” can have many nonscientific meanings. For example, it can mean “progress” and “descent with modifications.” Scientifically it is a term used to describe a changing the characteristics of living organisms (or species) over time. This change is based in biological terms on natural selection and drift. Evolution is an important concept in the field of biology today. It is a well-supported theory that has stood up to the test of time and a multitude of scientific studies. Evolution doesn't deal with God's presence or spiritual beliefs like other theories in science, like the Copernican or germ theory of diseases. Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change in a step-wise manner, as time passes. 에볼루션 코리아 evolutionkr.kr was referred to as the “Ladder of Nature” or 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 claims that different species of organisms share the same ancestry, which can be proven through fossils and other evidence. This is the current view on evolution, which is supported in a wide range of disciplines which include molecular biology. Although scientists aren't able to determine the exact mechanism by which organisms evolved however they are sure that the evolution of life on earth is a result of natural selection and genetic drift. People with advantages are more likely than others to live and reproduce. They transmit their genes on to the next generation. As time passes the gene pool gradually changes and develops into new species. Some scientists employ the term evolution in reference to large-scale change, such as the evolution of an animal from an ancestral one. Certain scientists, such as population geneticists, define the term “evolution” in a broad sense, talking about the net change in the frequency of alleles across generations. Both definitions are correct and palatable, but some scientists argue that allele-frequency definitions omit important features of evolution. Origins of Life One of the most crucial steps in evolution is the appearance of life. The emergence of life occurs when living systems start to develop at a micro scale, for instance within individual cells. The origins of life is an issue in a variety of disciplines, including biology, chemistry and geology. The origin of life is a topic that is of immense interest to scientists, as it is a challenge to the theory of evolution. It is often referred to “the mystery” of life or “abiogenesis.” The idea that life could arise from non-living matter was known as “spontaneous generation” or “spontaneous evolutionary”. This was a popular belief prior to Louis Pasteur's tests proved that the development of living organisms was not possible by the natural process. Many scientists still believe that it is possible to make the transition from nonliving substances to life. However, the conditions needed are extremely difficult to reproduce in the 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 is the sequence of extremely complex chemical reactions that cannot be predicted from the fundamental physical laws alone. These include the reading of long information-rich molecules (DNA or RNA) into proteins that carry out functions and the replication of these complex molecules to produce new DNA or RNA sequences. These chemical reactions can be compared to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is essential to begin the process of becoming a living organism. But, without life, the chemistry required to enable it does appear to work. Research in the area of abiogenesis requires collaboration between scientists from a variety of disciplines. This includes prebiotic chemists, planet scientists, astrobiologists geophysicists, geologists, and geophysicists. Evolutionary Changes The term “evolution” is typically used to describe the cumulative changes in the genetic characteristics of a population over time. These changes can result from adaptation to environmental pressures, as described in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection. This mechanism also increases the frequency of genes that offer a survival advantage in the species, leading to an overall change in the appearance of a group. These changes in evolutionary patterns are caused by mutations, reshuffling genes during sexual reproduction and the flow of genes. While reshuffling and mutation of genes occur in all living things, the process by which beneficial mutations become more common is referred to as natural selection. This is because, as we've mentioned earlier those with the beneficial trait tend to have a higher fertility rate than those without it. This variation in the number of offspring produced over many generations can result in a gradual shift in the average number of beneficial traits in the group. This is evident in the evolution of different 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 the form and shape of organisms can also aid in the creation of new species. The majority of changes are caused by a single mutation, although sometimes multiple occur at the same time. Most of these changes can be negative or even harmful however, a small percentage may have a positive effect on survival and reproduce with increasing frequency over time. Natural selection is a process that could result in the accumulation of change over time that eventually leads to a new species. Many people confuse the concept of evolution with the idea that traits inherited can be changed through conscious choice or use and abuse, a concept known as soft inheritance. This is a misunderstanding of the nature of evolution and of the actual biological processes that cause it. A more accurate description is that evolution is a two-step procedure involving the independent and often antagonistic forces of natural selection and mutation. Origins of Humans Modern humans (Homo Sapiens) evolved from primates, which is a group of mammal species that includes chimpanzees and gorillas. Our ancestral ancestors were walking on two legs, as shown by the oldest fossils. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In actual fact our closest relatives are the chimpanzees of the Pan genus. This includes pygmy and bonobos. The last common human ancestor and chimpanzees was born between 8 and 6 million years ago. As time has passed humans have developed a range of characteristics, such as bipedalism as well as the use of fire. They also invented advanced tools. But it's only in the last 100,000 years or so that most of the characteristics that differentiate us from other species have developed. These include language, large brain, the capacity to construct and use sophisticated tools, and a cultural diversity. Evolution occurs when genetic changes enable members of a group to better adapt to the environment. Natural selection is the process that triggers this adaptation. Certain characteristics are more desirable than others. The better adapted are more likely to pass on their genes to the next generation. This is the way all species evolve and the basis for the theory of evolution. Scientists call it the “law of Natural Selection.” The law states that species which have a common ancestor are likely to acquire similar traits in the course of time. This is because these traits help them to live and reproduce in their environment. Every organism has a DNA molecule that contains the information needed to control their growth. The DNA structure is composed of base pairs that are arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines the phenotype or the individual's unique appearance and behavior. Different mutations and reshuffling of the genetic material (known as alleles) during sexual reproduction cause variations in a population. Fossils of the earliest human species, Homo erectus and Homo neanderthalensis were discovered in Africa, Asia, and Europe. These fossils, despite a few differences in their appearance all support the hypothesis of modern humans' origins in Africa. The fossil evidence and genetic evidence suggest that early humans moved from Africa into Asia and then Europe.