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The Berkeley Evolution Site The Berkeley site has resources that can help students and educators learn about and teach evolution. The resources are organized into optional learning paths like “What does T. rex look like?” Charles Darwin's theory on natural selection explains how creatures who are better able to adapt to changes in their environment survive over time and those who do not end up becoming extinct. This process of evolution is the basis of science. What is Evolution? The term “evolution” can have many nonscientific meanings. For instance “progress” or “descent with modification.” Scientifically it is a term used to describe a changing the characteristics of organisms (or species) over time. In terms of biology this change is based on natural selection and genetic drift. Evolution is a key principle in the field of biology today. It is a concept that has been tested and proven by a myriad of scientific tests. Evolution does not deal with God's presence or spiritual beliefs, unlike many other scientific theories such as the Copernican or germ theory of diseases. Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a gradual manner over time. This was known 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 asserts that all species of organisms share common ancestors that can be traced through fossils and other evidence. This is the modern view of evolution, and is supported by a variety of research lines in science which includes molecular genetics. Scientists don't know how organisms evolved but they are sure that natural selection and genetic drift is the reason for the evolution of life. People with traits that are advantageous are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. As time passes this leads to an accumulation of changes to the gene pool that gradually lead to new species and types. Certain scientists also use the term”evolution” to describe large-scale evolutionary changes, such as the formation of an entirely new species from an ancestral species. Some scientists, like population geneticists define evolution in a more broad sense by referring to the net change in allele frequency over generations. Both definitions are correct and palatable, but some 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 development of life. This occurs when living systems begin to develop at a micro-level – within cells, for example. The origins of life is a topic in many disciplines such as geology, chemistry, biology and chemistry. The origin of life is an area that is of immense interest to scientists, as it is a challenge to the theory of evolution. It is often referred to as “the mystery of life” or “abiogenesis.” Traditionally, the notion that life can emerge 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 creation of life to happen through an entirely natural process. Many scientists still believe that it is possible to make the transition from nonliving substances to living. However, the conditions required are extremely difficult to replicate in a laboratory. This is why researchers investigating the beginnings of life are also interested in determining the physical properties of the early Earth and other planets. The life-cycle of a living organism is dependent on a variety of complex chemical reactions, which cannot be predicted by basic physical laws. 에볼루션 게이밍 include the reading and the replication of complex molecules, such as DNA or RNA, to produce proteins that perform a specific function. These chemical reactions are often compared to the chicken-and-egg dilemma of how life came into existence in the first place. The appearance of DNA/RNA and proteins-based cell machinery is vital for the onset of life, but without the development of life, the chemistry that makes it possible does not appear to work. Abiogenesis research requires collaboration among scientists from various fields. This includes prebiotic scientists, astrobiologists, and planetary scientists. Evolutionary Changes Today, the word evolution is used to describe the gradual changes in genetic traits over time. These changes can be the result of adaptation to environmental pressures as explained in Darwinism. This latter mechanism increases the number of genes that offer an advantage for survival in an animal, resulting in an overall change in the appearance of the group. These changes in evolutionary patterns are caused by mutations, reshuffling of genes during sexual reproduction and the flow of genes. While reshuffling and mutations of genes happen in all living organisms and the process by which beneficial mutations are more frequent is known as natural selection. This happens because, as we've mentioned earlier, those individuals with the beneficial trait tend to have a higher fertility rate than those without it. Over many generations, this difference in the number of offspring produced can result in an inclination towards a shift in the average amount of desirable traits in a population. This can be seen in the evolution of various beak designs on finches that are found in the Galapagos Islands. They have created these beaks to ensure they can get food more quickly in their new home. These changes in shape and form can aid in the creation of new organisms. The majority of changes are caused by one mutation, but sometimes several occur simultaneously. Most of these changes may be harmful or neutral however, a few can have a beneficial impact on survival and reproduction and increase their frequency over time. This is the mechanism of natural selection and it is able to eventually result in the cumulative changes that ultimately lead to a new species. Some people confuse the notion of evolution with the idea that inherited characteristics can be changed through conscious choice, or through use and abuse, a notion known as soft inheritance. This is a misinterpretation of the nature of evolution, and of the actual biological processes that lead to it. A more accurate description of evolution is that it involves a two-step process, involving the independent, and often competing, forces of natural selection and mutation. Origins of Humans Humans today (Homo sapiens) evolved from primates, a group of mammals that also includes chimpanzees, gorillas, and bonobos. Our ancestors walked on two legs, as shown by the first fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In extra resources are the closest connected to chimpanzees belonging to the Pan genus which includes bonobos and pygmy chimpanzees. The last common ancestor shared between modern humans and chimpanzees was between 8 and 6 million years old. Humans have evolved a wide range of characteristics over time including bipedalism, the use of fire, and the development of advanced tools. It is only in the last 100,000 years or so that most of the traits that distinguish us from other species have developed. They include a huge brain that is complex human ability to build and use tools, and cultural diversity. The process of evolution occurs when genetic changes allow individuals in a group to better adapt to their environment. Natural selection is the process that drives this change. Certain characteristics are more desirable than others. The ones who are better adapted are more likely to pass on their genes to the next generation. This is the way that all species evolve, and it is the foundation of the theory of evolution. Scientists refer to it as the “law of natural selection.” The law states that species that share an ancestor will tend to develop similar traits as time passes. This is because these traits make it easier to survive and reproduce within their environment. Read More Listed here have DNA molecules, which contains the information needed to control their growth and development. The DNA molecule consists of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases within each strand determines phenotype, or the individual's characteristic appearance and behavior. Variations in mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction cause variations in a population. Fossils from the first human species, Homo erectus, and Homo neanderthalensis have been found in Africa, Asia and Europe. While there are some differences between them, these fossils all support the idea that modern humans first appeared in Africa. The genetic and fossil evidence suggests that early humans left Africa and migrated to Asia and Europe.