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The Berkeley Evolution Site The Berkeley site has resources that can help students and teachers to understand and teach about evolution. The materials are arranged in various learning paths that can be used in a variety of ways like “What does T. rex look like?” Charles Darwin's theory of natural selection explains that over time creatures that are better able to adapt biologically to changing environments thrive, and those that don't become extinct. Science is all about this process of evolutionary change. What is Evolution? The term “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 refers to the process of change of characteristics in a species or species. In biological terms, this change is due to natural selection and genetic drift. Evolution is a fundamental concept in modern biology. It is a theory that has been confirmed by a myriad of scientific tests. Evolution doesn't deal with spiritual beliefs or God's presence like other theories of science, such as the Copernican or germ theory of disease. 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-like manner, as time passes. This was known as the “Ladder of Nature” or scala Naturae. Charles Lyell first used this term in 1833 in his Principles of Geology. Darwin revealed 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 common ancestors that can be traced using fossils and other evidence. This is the modern view of evolution that is supported by a variety of lines of scientific research that include molecular genetics. Scientists do not know how organisms have evolved however they are certain that natural selection and genetic drift is the reason for the development of life. Individuals with advantageous characteristics are more likely to live and reproduce. They pass on their genes to the next generation. Over time, this results in an accumulation of changes to the gene pool which gradually create new species and forms. Some scientists also use the term”evolution” to refer to large-scale changes in evolutionary processes, such as the formation of the new species from an ancestral species. Some scientists, like population geneticists, define evolution in a more broad sense by using the term “net change” to refer to the variation in the frequency of alleles over generations. Both definitions are valid and palatable, but some scientists believe that allele-frequency definitions miss important aspects of the evolutionary process. Origins of Life A key step in evolution is the appearance of life. The emergence of life happens when living systems start to develop at a micro level, like within individual cells. The origins of life are an issue in a variety of disciplines that include geology, chemistry, biology and chemistry. The nature of life is a subject that is of immense interest to scientists because it challenges the theory of evolution. It is sometimes referred to as “the mystery” of life or “abiogenesis.” The notion that life could arise from non-living objects was referred to as “spontaneous generation” or “spontaneous evolutionary”. It was a common belief prior to Louis Pasteur's experiments proved that the creation of living organisms was not achievable through the natural process. Many scientists believe that it is possible to go from nonliving substances to life. However, the conditions that are required are extremely difficult to replicate in the laboratory. This is why 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 variety of complex chemical reactions which are not predicted by simple physical laws. These include the reading and replication of complex molecules, like DNA or RNA, in order to make proteins that perform a specific function. These chemical reactions are often compared with the chicken-and-egg dilemma of how life began: The emergence of DNA/RNA and protein-based cell machinery is essential to the birth of life, however, without the development of life, the chemistry that makes it possible is not working. 에볼루션 requires collaboration between researchers from different disciplines. This includes prebiotic chemists the astrobiologists, the planet scientists geophysicists and geologists. Evolutionary Changes The term “evolution” is typically used to describe the cumulative changes in the genetic traits of populations 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 from natural selection. This mechanism also increases the frequency of genes that provide the advantage of survival for a species, resulting in an overall change in the appearance of an entire group. The specific mechanisms behind these changes in evolutionary process include mutation, reshuffling of genes during sexual reproduction, and gene flow between populations. While mutation and reshuffling of genes are common in all organisms The process through which beneficial mutations are more prevalent is called natural selection. As previously mentioned, those who possess the desirable trait have a higher reproductive rate than those that do not. This differential in the number of offspring that are produced over a long period of time can result in a gradual shift in the average number advantageous traits in the group. This can be seen in the evolution of various beak shapes on finches from the Galapagos Islands. They have developed these beaks so they can get food more easily in their new habitat. These changes in form and shape can also help create new organisms. The majority of changes are caused by one mutation, however sometimes multiple occur simultaneously. Most of these changes are neither harmful nor even detrimental to the organism, however, a small proportion of them can have a positive impact on the longevity and reproduction of the species, thus increasing the frequency of these changes 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. Many people confuse the concept of evolution with the idea that inherited characteristics can be altered through conscious choice or by use and abuse, which is called soft inheritance. This is a misinterpretation of the nature of evolution and of the actual biological processes that trigger it. It is more accurate to say that the process of evolution is a two-step, separate process that involves the forces of natural selection as well as mutation. Origins of Humans Modern humans (Homo Sapiens) evolved from primates, a group of mammal species which includes gorillas and chimpanzees. The earliest human fossils indicate that our ancestors were bipeds. They were walkers with two legs. Genetic and biological similarities show that we share the same ancestry with chimpanzees. In reality, we are most closely with chimpanzees in the Pan Genus, which includes bonobos and pygmy-chimpanzees. The last common ancestor between modern humans and chimpanzees dated between 8 and 6 million years old. Over time, humans have developed a number of characteristics, such as bipedalism and the use fire. They also created 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 brain that is complex, the ability of humans to construct and use tools, and the diversity of our culture. Evolution occurs when genetic changes allow members of a population to better adapt to their surroundings. This adaptation is driven by natural selection, a process whereby certain traits are preferred over other traits. The ones who are better adaptable are more likely to pass their genes on to the next generation. This is how all species evolve and is the basis of the theory of evolution. Scientists call it the “law of Natural Selection.” The law states that species that have an ancestor in common will tend to develop similar characteristics over time. This is because these traits allow them to live and reproduce in their environment. Every organism has DNA molecules, which is the source of information that helps guide their growth and development. click through the next webpage consists of base pairs arranged spirally around sugar molecules and phosphate molecules. Info of bases within each strand determines phenotype or the individual's unique appearance and behavior. Variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles). Fossils from the early 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 evidence from fossils and genetics suggests that early humans left Africa and moved to Asia and Europe.