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The Berkeley Evolution Site Teachers and students who browse the Berkeley site will find a wealth of resources to help them understand and teach evolution. The materials are arranged in different learning paths like “What does T. rex look like?” Charles Darwin's theory of natural selection explains how over time, animals that are more able to adapt to changing environments do better than those that don't become extinct. This process of evolution is the main focus of science. What is Evolution? The term “evolution” can be used to refer to a variety of nonscientific meanings. For instance, it can mean “progress” and “descent with modifications.” Scientifically it refers to a process of changes in the traits of living organisms (or species) over time. In biological terms the change is based on natural selection and genetic drift. Evolution is the central tenet of modern biology. It is a concept that has been confirmed by a myriad of scientific tests. In contrast to other theories in science like the Copernican theory or the germ theory of disease, evolution 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 change in a gradual manner over time. They referred to this as the “Ladder of Nature” or the 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 an ancestry that can be proven through fossils and other evidence. This is the current view of evolution, which is supported in many scientific fields that include molecular biology. While scientists don't know exactly how organisms evolved however they are sure that the evolution of life on earth is the result of natural selection and genetic drift. 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 slowly changes and develops into new species. Some scientists also use the term”evolution” to refer to large-scale changes in evolutionary processes such as the creation of the new species from an ancestral species. Other scientists, like population geneticists, define it more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are valid and reliable, although some scientists argue that the definition of allele frequency is lacking important features of the evolutionary process. Origins of Life The birth of life is an essential step in the process of evolution. This happens when living systems begin to evolve at a micro-level – within cells, for example. The origins of life is an issue in a variety of disciplines, including biology, chemistry and geology. The nature of life is a subject of interest in science, as it challenges the theory of evolution. It is sometimes referred to “the mystery” of life or “abiogenesis.” Traditionally, the notion that life could emerge from nonliving objects is known as spontaneous generation, or “spontaneous evolution.” This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the development of life to occur by a purely natural process. Many scientists still think it is possible to transition from living to nonliving substances. However, the conditions that are required are extremely difficult to replicate in labs. This is why researchers investigating the nature of life are also interested in determining the physical properties of the early Earth and other planets. The growth of life is dependent on a variety of complex chemical reactions, which cannot be predicted by the basic physical laws. These include the reading of long information-rich molecules (DNA or RNA) into proteins that perform a function and the replication of these intricate molecules to create new DNA or sequences of RNA. These chemical reactions are often compared with the chicken-and-egg issue of how life first appeared: The emergence of DNA/RNA and protein-based cell machinery is essential to the birth of life, however, without the appearance of life the chemical reaction that is the basis for it isn't working. Abiogenesis research requires collaboration between scientists from different fields. This includes prebiotic chemists the astrobiologists, the planet scientists geophysicists and geologists. Evolutionary Changes The word evolution is usually used to describe the accumulated changes in genetic characteristics of an entire population over time. These changes can result from the response 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 process increases the frequency of genes that confer a survival advantage in an animal, resulting in an overall change in the appearance of a group. my website behind these evolutionary changes are mutation or reshuffling genes during sexual reproduction, as well as gene flow between populations. Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo mutations and reshuffles in their genes. As mentioned above, those who possess the desirable trait have a higher reproductive rate than those that do not. Over the course of several generations, this difference in the numbers of offspring produced can result in an inclination towards a shift in the average amount of desirable characteristics in a particular population. This can be seen in the evolution of various beak shapes on finches from the Galapagos Islands. They have created these beaks to ensure that they can access food more quickly in their new home. These changes in form and shape can also aid in the creation of new species. The majority of changes are caused by a single mutation, however sometimes multiple occur at once. The majority of these changes are not harmful or even detrimental to the organism, however a small portion of them could 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 process of natural selection and it can be a time-consuming process that produces the gradual changes that ultimately lead to the creation of a new species. Some people confuse the idea of evolution with the notion that inherited characteristics can be changed through conscious choice, or through use and abuse, a notion known as soft inheritance. This is a misunderstanding of the biological processes that lead to the process of evolution. A more precise description is that evolution involves a two-step process, which involves the separate and often antagonistic forces of mutation and natural selection. 무료에볼루션 of Humans Humans of today (Homo sapiens) evolved from primates, a group of mammals that includes chimpanzees and gorillas and bonobos. Our predecessors walked on two legs, as demonstrated by the earliest fossils. Genetic and biological similarities show that we share a close relationship with chimpanzees. In reality, our closest relatives are the chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor and chimpanzees was between 8 and 6 million years ago. Humans have evolved a wide range of characteristics over time including bipedalism, the use of fire and advanced tools. It's only in the last 100,000 years that we've developed the majority of our important traits. These include a big, complex brain and the capacity of humans to construct and use tools, as well as cultural diversity. Evolution occurs when genetic changes allow individuals in a group to better adapt to their environment. This adaptation is driven by natural selection, which is a process by which certain traits are more desirable than others. Those with the better adaptations are more likely to pass on their genes to the next generation. This is how all species evolve and forms the basis of the theory of evolution. Scientists call this the “law of natural selection.” The law states that species that have a common ancestor are more likely to develop similar characteristics over time. This is because these traits allow them to survive and reproduce in their environments. Every organism has a DNA molecule, which is the source of information that helps direct their growth and development. The DNA structure is composed of base pair that are arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines phenotype or the individual's unique appearance and behavior. The 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, and Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite some differences in their appearance, all support the idea of modern humans' origins in Africa. The genetic and fossil evidence suggests that the first humans left Africa and moved to Asia and Europe.