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The Berkeley Evolution Site The Berkeley site contains resources that can help students and educators understand and teach evolution. The materials are organized in optional learning paths like “What does T. rex look like?” Charles Darwin's theory of natural selection states that in time, creatures better able to adapt biologically to changing environments survive and those that don't become extinct. This process of evolution in biology is the main focus of science. 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 is used to describe the process of changing characteristics over time in organisms or species. The reason for this change is biological terms on natural selection and drift. Evolution is a key tenet in modern biology. It is a concept that has been verified by a myriad of scientific tests. In contrast to other theories in science, such as the Copernican theory or the germ theory of disease, evolution 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 gradual manner, as time passes. They called this 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 published in the early 1800s. It states that all species of organisms have an ancestry that can be traced using fossils and other evidence. This is the modern view of evolution, and is supported by a variety of lines of scientific research that include molecular genetics. While scientists do not know exactly how organisms evolved but they are certain that the evolution of life on earth is the result of natural selection and genetic drift. People with advantages are more likely than others to survive and reproduce. They transmit their genes to the next generation. As time passes this leads to a gradual accumulation of changes to the gene pool which gradually lead to new species and types. Certain scientists also use the term evolution to describe large-scale evolutionary changes such as the creation of a new species from an ancestral species. Others, like population geneticists, define it more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are acceptable and precise however, some scientists claim that the allele-frequency definition is missing crucial aspects of the evolutionary process. Origins of Life The emergence of life is a crucial stage in evolution. This occurs when living systems begin to develop at the micro level – within individual cells, for instance. The origins of life is one of the major topics in various disciplines such as biology, chemistry and geology. The origin of life is a topic of great interest in science because it is a challenge to the theory of evolution. It is often referred to as “the mystery of life,” or “abiogenesis.” Traditionally, the idea that life can emerge from nonliving things is known as spontaneous generation, or “spontaneous evolution.” 에볼루션 바카라 무료 was a common belief before Louis Pasteur's experiments showed that it was impossible for the emergence of life to happen through an entirely natural process. Many scientists still believe that it is possible to go from nonliving substances to life. However, the conditions needed are extremely difficult to reproduce in a laboratory. This is why researchers studying the beginnings of life are also keen to understand the physical properties of the early Earth and other planets. Additionally, the evolution of life is dependent on the sequence of extremely complex chemical reactions that cannot be predicted from the fundamental physical laws alone. This includes the conversion of long information-rich molecules (DNA or RNA) into proteins that carry out some function as well as the replication of these complex molecules to produce new DNA or RNA sequences. These chemical reactions are often compared with the chicken-and-egg dilemma of how life came into existence with the appearance of DNA/RNA and protein-based cell machinery is crucial for the beginning of life, however, without the development of life the chemical reaction that is the basis for it does not appear to work. Abiogenesis research requires collaboration with researchers from different fields. This includes prebiotic scientists, astrobiologists and planet scientists. Evolutionary Changes Today, the word evolution is used to describe the general changes in genetic traits over time. These changes can be the result of adapting to environmental pressures, as described in Darwinism. This process increases the number of genes that offer an advantage for survival in an animal, resulting in an overall change in the appearance of a group. The specific mechanisms behind these evolutionary changes include mutation or reshuffling genes during sexual reproduction, and gene flow between populations. Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo changes and reshuffles of genes. As noted above, individuals who possess the desirable characteristic have a higher reproduction rate than those who don't. This difference in the number of offspring produced over a number of generations could result in a gradual change in the average number advantageous traits within a group. This can be seen in the evolution of various beak shapes for finches from the Galapagos Islands. They have developed these beaks in order they can get food more easily in their new environment. These changes in shape and form could also aid in the creation of new species. The majority of the changes that occur are caused by a single mutation, but sometimes, several changes occur simultaneously. The majority of these changes are not harmful or even detrimental to the organism, however a small portion of them could be beneficial to the survival of the organism and its reproduction, thereby increasing their frequency in the population over time. This is the mechanism of natural selection and it can be a time-consuming process that produces the gradual changes that eventually lead to a new species. Many people confuse the concept of evolution with the notion that traits inherited can be changed through conscious choice or by use and abuse, a notion known as soft inheritance. This is a misunderstanding of the biological processes that lead to evolution. A more precise description is that evolution is a two-step process which involves the separate and often conflicting forces of natural selection and mutation. Origins of Humans Humans of today (Homo sapiens) evolved from primates, a group of mammals that also includes chimpanzees, gorillas, and bonobos. Our ancestral ancestors were walking on two legs, as evidenced by the earliest fossils. Genetic and biological similarities suggest that we have the same ancestry with Chimpanzees. In reality our closest relatives are chimpanzees belonging to the Pan genus. This includes pygmy and bonobos. The last common human ancestor and chimpanzees lived between 8 and 6 million years ago. As time has passed humans have developed a range of traits, including bipedalism as well as the use of fire. They also developed advanced tools. But it's only in the last 100,000 years or so that the majority of the essential traits that distinguish us from other species have been developed. These include language, a large brain, the capacity to build and use sophisticated tools, and a cultural diversity. Evolution occurs when genetic changes enable members of the group to better adapt to their environment. Natural selection is the process that drives this change. Certain characteristics are more desirable than others. The better adjusted are more likely to pass on their genes to the next generation. This is how all species evolve and is the basis for the theory of evolution. Scientists refer to it as the “law of natural selection.” The law states that species which share an ancestor will tend to acquire similar traits over time. This is because these traits make it easier for them to live and reproduce in their environments. Every organism has a DNA molecule, which is the source of information that helps guide their growth and development. The DNA molecule is composed of base pairs that are arranged in a spiral around phosphate molecules and sugar molecules. The sequence of bases found in each string determines the phenotype or the appearance and behavior of a person. A variety of mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction cause variation in a population. Fossils from the first human species, Homo erectus and Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite differences in their appearance, all support the idea of modern humans' origins in Africa. The fossil and genetic evidence suggests that the first humans left Africa and migrated to Asia and Europe.