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The Berkeley Evolution Site Teachers and students who browse the Berkeley site will find a wealth of resources to aid in understanding and teaching evolution. The resources are organized into optional learning paths, such as “What does T. rex look like?” Charles Darwin's theory of natural selection describes how species who are better able to adapt to changes in their environments survive longer and those who do not disappear. Science is about this process of evolution. What is Evolution? The word evolution has many nonscientific meanings. For instance “progress” or “descent with modification.” Scientifically it refers to a process of changing the characteristics of living organisms (or species) over time. This change is based in biological terms on natural selection and drift. Evolution is a fundamental concept in modern biology. It is a concept that has been proven by a myriad of scientific tests. 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 religion or the existence of God. Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical characteristics were predetermined to change, in a step-wise manner, as time passes. They referred to this as 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. Darwin presented his theory of evolution in his book On the Origin of Species, written in the early 1800s. It states that all species of organisms share an ancestry that can be traced through fossils and other evidence. This is the modern view of evolution, and is supported by a variety of lines of research in science which includes molecular genetics. While scientists do not know exactly how organisms developed however they are sure that the evolution of life on earth is a result of natural selection and genetic drift. Individuals with advantageous characteristics are more likely to live and reproduce. These individuals pass on their genes on to the next generation. In time this leads to gradual changes to the gene pool, which eventually result in new species and forms. Some scientists employ the term evolution in reference to large-scale changes, like the development of one species from an ancestral one. Certain scientists, such as population geneticists define evolution in a more broad sense by using the term “net change” to refer to the change in allele frequency over generations. Both definitions are acceptable and precise however some scientists believe that the allele-frequency definition is missing important features of the evolutionary process. Origins of Life The birth of life is an essential step in evolution. The emergence of life occurs when living systems start to develop at a micro level, such as within cells. The origins of life is one of the major topics in various disciplines that include biology, chemistry, and geology. The question of how living organisms began is a major topic in science due to it being an enormous challenge to the theory of evolution. It is often referred to “the mystery” of life or “abiogenesis.” The idea that life could be born from non-living things was called “spontaneous generation” or “spontaneous evolutionary”. It was a popular belief prior to Louis Pasteur's tests showed that the development of living organisms was not achievable through a natural process. Many scientists still believe it is possible to go from nonliving materials to living. The conditions required to create life are difficult to replicate in a laboratory. Researchers interested in the evolution and origins of life are also eager to know the physical properties of the early Earth as well as other planets. Additionally, the evolution of life depends on the sequence of extremely complex chemical reactions that cannot be predicted based on basic physical laws on their own. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that carry out functions as well as the replication of these intricate molecules to generate new DNA or sequences of RNA. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, protein-based cell machinery, is essential to begin the process of becoming a living organism. However, without 에볼루션 바카라 사이트 , the chemistry that is required to create it does appear to work. Research in the area of abiogenesis requires cooperation among scientists from a variety of disciplines. This includes prebiotic chemists, astrobiologists, planetary scientists geophysicists, geologists, and geophysicists. Evolutionary Changes The term “evolution” today is used to describe the general changes in genetic traits over time. These changes may result from adaptation to environmental pressures, as explained in the article on Darwinism (see the entry on Charles Darwin for background), or from natural selection. This mechanism also increases the frequency of genes that offer the advantage of survival for an animal, resulting in an overall change in the appearance of a group. These evolutionary changes are triggered by mutations, reshuffling of genes in the process of sexual reproduction, and also by gene flow. Natural selection is the process that makes beneficial mutations more frequent. All organisms undergo changes and reshuffles of their genes. As noted above, individuals who possess the desirable trait have a higher reproductive rate than those who do not. This difference in the number of offspring produced over many generations can result in a gradual change in the number of advantageous characteristics in the group. This can be seen in the evolution of different beak shapes for finches from the Galapagos Islands. They have created these beaks to ensure they can get food more easily in their new environment. These changes in the shape and appearance of organisms could also be a catalyst for the creation of new species. The majority of the changes that occur are caused by a single mutation, but occasionally, multiple mutations occur at the same time. The majority of these changes are neutral or even harmful to the organism, however, a small proportion of them can have a positive impact on the longevity and reproduction of the species, thus increasing their frequency in the population over time. This is the mechanism of natural selection, and it is able to eventually result in the accumulating changes that eventually result in an entirely new species. Many people confuse the concept of evolution with the idea that traits inherited can be changed through conscious choice or by use and abuse, which is called soft inheritance. This is a misinterpretation of the biological processes that lead to evolution. A more precise description is that evolution is a two-step procedure which involves the separate and often conflicting forces of natural selection and mutation. Origins of Humans Humans today (Homo sapiens) evolved from primates – a group of mammals that includes chimpanzees, gorillas, and bonobos. Our ancestors walked on two legs, as shown by the earliest fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In actual fact our closest relatives are the chimpanzees from the Pan genus. This includes pygmy and bonobos. The last common human ancestor as well as chimpanzees was between 8 and 6 million years ago. As time has passed humans have developed a number of characteristics, including bipedalism as well as the use of fire. They also created advanced tools. However, it is only in the past 100,000 years or so that the majority of the important characteristics that differentiate us from other species have been developed. They include language, a large brain, the ability to build and use complex tools, as well as cultural diversity. Evolution occurs when genetic changes allow members of the group to better adapt to the environment. Natural selection is the mechanism that drives this change. Certain characteristics are more desirable than others. The ones who are better adapted are more likely to pass their genes on to the next generation. This is the way all species evolve, and the basis of the theory of evolution. Scientists call this the “law of natural selection.” The law states species that have a common ancestor are likely to develop similar traits over time. It is because these traits make it easier to reproduce and survive within their environment. All organisms possess a DNA molecule that contains the information needed to guide their growth. The DNA molecule is composed of base pairs that are spirally arranged around sugar molecules and phosphate molecules. The sequence of bases within each strand determines phenotype, or the individual's characteristic appearance and behavior. Variations in a population are caused by reshufflings and mutations 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 differences in their appearance, all support the theory of the origins of modern humans in Africa. Genetic and fossil evidence also suggest that early humans moved out of Africa into Asia and then Europe.