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The Berkeley Evolution Site Teachers and students who browse the Berkeley site will find 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 equipped to adapt to changes in their environments over time, and those that do not end up becoming extinct. This process of biological evolution is the basis of science. What is Evolution? The word evolution can have a variety of meanings that are not scientific. For instance it could refer to “progress” and “descent with modifications.” It is an academic term that is used to describe the process of change of characteristics in a species or species. In biological terms this change is based on natural selection and genetic drift. Evolution is an important tenet in the field of biology today. It is a concept that has been tested and confirmed by a myriad of scientific tests. Evolution does not deal with God's presence or spiritual beliefs like other theories of science, such as the Copernican or germ theory of disease. Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change, in a step-wise way, over time. This was called 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. Darwin presented his theory of evolution in his book On the Origin of Species, written in the early 1800s. It claims that different species of organisms share a common ancestry, which can be determined through fossils and other evidence. This is the current view of evolution, which is supported by a variety of areas of science 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 a result of natural selection and genetic drift. People with desirable traits are more likely than others to survive and reproduce. These individuals pass on their genes to the next generation. Over time the gene pool gradually changes and evolves into new species. Certain scientists also use the term evolution to describe large-scale evolutionary changes like the creation of the new species from an ancestral species. Other scientists, like population geneticists, define the term “evolution” more broadly by referring a net change in the frequency of alleles across generations. Both definitions are acceptable and precise however, some scientists claim that the allele-frequency definition omits crucial aspects of the evolutionary process. Origins of Life The birth of life is a key stage in evolution. This occurs when living systems begin to evolve at the micro level, within individual cells, for example. The origins of life are an important topic in a variety of fields, including biology and the field of chemistry. The nature of life is a topic of great interest in science because it is a challenge to the theory of evolution. It is often called “the mystery of life” or “abiogenesis.” The idea that life could be born from non-living objects was referred to as “spontaneous generation” or “spontaneous evolutionary”. This was a common belief prior to Louis Pasteur's tests proved that the creation of living organisms was not achievable through the natural process. Many scientists believe it is possible to go from living to nonliving substances. However, the conditions that are required are extremely difficult to replicate in a laboratory. Researchers studying the origins of life are also interested in understanding the physical properties of the early Earth and other planets. The development of life is dependent on a number of complex chemical reactions, that are not predicted by basic physical laws. These include the transformation of long information-rich molecules (DNA or RNA) into proteins that carry out a function as well as the replication of these complex molecules to produce new DNA or RNA sequences. These chemical reactions can be compared to a chicken-and egg problem: the emergence and development of DNA/RNA, protein-based cell machinery, is necessary to begin the process of becoming a living organism. However without life, the chemistry required to enable it appears to be working. Abiogenesis research requires collaboration with scientists from various fields. This includes prebiotic scientists, astrobiologists and planet scientists. Evolutionary Changes Today, the word evolution is used to describe cumulative changes in genetic characteristics over time. These changes could result from the response to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection. This is a process that increases the frequency of genes in a species that offer an advantage in survival over others which results in an ongoing change in the overall appearance of a population. These evolutionary changes are caused by mutations, reshuffling genes in the process of sexual reproduction, and also by the flow of genes. 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 that do not. Over the course of several generations, this differential in the number of offspring born can result in gradual changes in the number of advantageous traits within a group of. This can be seen in the evolution of various beak designs on finches that are found in the Galapagos Islands. They have developed these beaks so that they can access food more quickly in their new home. These changes in shape and form could also aid in the creation of new species. The majority of the changes that take place are caused by a single mutation, but occasionally several will happen at the same time. Most of these changes are not harmful or even harmful to the organism but a small percentage can have a positive impact on the longevity and reproduction of the species, thus increasing their frequency in the population over time. Natural selection is a process that causes the accumulating change over time that eventually leads to the creation of a new species. Some people mistakenly associate evolution with the concept of soft inheritance, which is the idea that inherited traits can be altered by conscious choice or abuse. 에볼루션코리아 is a misunderstanding of the biological processes that lead to evolution. It is more precise to say that evolution is a two-step, separate process, which involves the forces of natural selection and mutation. 에볼루션 코리아 of Humans Humans of today (Homo sapiens) evolved from primates – a species of mammals that includes gorillas, chimpanzees, and bonobos. Our ancestors walked on two legs, as evidenced by the earliest fossils. Biological and genetic similarities indicate that we share the same ancestry with the chimpanzees. In actual fact our closest relatives are chimpanzees belonging to the Pan genus. This includes pygmy and bonobos. The last common human ancestor and chimpanzees was born between 8 and 6 million years ago. Over time, humans have developed a variety of traits, including bipedalism and the use fire. They also invented advanced tools. It is only in the past 100,000 years or so that most of the traits that distinguish us from other species have developed. They include language, a large brain, the ability to create and utilize sophisticated tools, and a cultural diversity. Evolution occurs when genetic changes enable members of a group to better adapt to their environment. This adaptation is driven by natural selection, a process whereby certain traits are preferred over others. The better adaptable are more likely to pass on their genes to the next generation. This is how all species evolve and is the foundation for the theory of evolution. Scientists refer to this as the “law of natural selection.” The law states that species that have an ancestor in common will tend to develop similar traits in the course of time. This is because the characteristics make it easier for them to survive and reproduce in their environments. All organisms possess a DNA molecule that contains the information needed to control their growth. The DNA molecule is made up of base pairs that are arranged in a spiral around phosphate molecules and sugar molecules. The sequence of bases within each strand determines phenotype or the individual's unique appearance and behavior. 에볼루션코리아 in a population can be 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 discovered in Africa, Asia, and Europe. These fossils, despite differences in their appearance all support the idea of the origins of modern humans in Africa. The fossil evidence and genetic evidence suggest that early humans migrated from Africa into Asia and then Europe.