The Berkeley Evolution Site
Teachers and students who browse the Berkeley site will find a wealth of resources to aid in understanding and teaching evolution. The resources are arranged into different learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory on natural selection explains how creatures who are better equipped to adapt biologically to changing environments over time, and those who do not end up becoming 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 example it could refer to "progress" and "descent with modifications." It is scientifically based and is used to describe the process of change of characteristics over time in organisms or species. In biological terms the change is based on natural selection and genetic drift.
Evolution is an important tenet in modern biology. It is a well-supported theory that has stood up to the test of time and thousands of scientific tests. Evolution does not deal with spiritual beliefs or God's presence, unlike many other theories of science, 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 stepped-like manner over time. They referred to this as the "Ladder of Nature" or the scala naturae. Charles Lyell used the term to describe this idea 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 asserts that different species of organisms have the same ancestry, which can be traced through fossils and other lines of evidence. This is the current perspective on evolution, which is supported by a variety of areas of science which include molecular biology.
While scientists don't know exactly how organisms evolved, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. People with desirable traits are more likely to survive and reproduce, and these individuals transmit their genes to the next generation. As time passes the gene pool slowly changes and develops into new species.
Certain scientists use the term"evolution" in reference to large-scale changes, like the evolution of a species from an ancestral one. Certain scientists, such as population geneticists define evolution in a broad sense, using the term "net change" to refer to the change in the frequency of alleles across generations. Both definitions are valid and reliable however, some scientists claim that the definition of allele frequency is lacking crucial aspects of the evolutionary process.
Origins of Life
The emergence of life is a crucial step in the process of evolution. The emergence of life occurs when living systems begin to evolve at a micro level, like within individual cells.
The origins of life are an important issue in many areas, including biology and the field of chemistry. The origin of life is an area of interest in science because it is a challenge to the theory of evolution. It is often called "the mystery of life," or "abiogenesis."
Traditionally, the belief that life could emerge from nonliving objects is known as spontaneous generation or "spontaneous evolution." This was a popular view before Louis Pasteur's research showed that it was impossible for the creation of life to be a result of an entirely natural process.
Many scientists still believe that it is possible to go from nonliving materials to living. However, the conditions that are required are extremely difficult to reproduce in the laboratory. Researchers interested in the origins and development of life are also keen to learn about the physical characteristics of the early Earth as well as other planets.
Furthermore, the growth of life is dependent on an intricate sequence of chemical reactions that cannot be predicted from basic physical laws alone. These include the reading and the replication of complex molecules, like DNA or RNA, to produce proteins that perform a particular function. These chemical reactions are often compared to the chicken-and-egg dilemma of how life came into existence in the first place. The development of DNA/RNA as well as proteins-based cell machinery is vital for the beginning of life, however, without the emergence of life, the chemical process that allows it does not appear to work.
Abiogenesis research requires collaboration among researchers from different disciplines. This includes prebiotic chemists, the astrobiologists, the planet scientists geophysicists and geologists.
discover here , the word evolution is used to describe cumulative changes in genetic characteristics over time. These changes may result from the response to environmental pressures as explained in the article on Darwinism (see the entry on Charles Darwin for background) or natural selection.
This is a method that increases the frequency of those genes in a species which confer a survival advantage over others, resulting in a gradual change in the overall appearance of a particular population. These evolutionary changes are caused by mutations, reshuffling genes in the process of sexual reproduction, and also by the flow of genes.
While reshuffling and mutation of genes happen in all organisms The process through which beneficial mutations become more common is referred to as natural selection. This occurs because, as we've mentioned earlier those with the beneficial trait tend to have a higher reproductive rate than those with it. Over the course of many generations, this difference in the numbers of offspring born can result in gradual changes in the average number of advantageous traits within a group of.
An excellent example is the increase in the size of the beaks on different species of finches in the Galapagos Islands, which have evolved different shaped beaks that allow them to easily access food in their new habitat. These changes in shape and form can aid in the creation of new organisms.
The majority of changes are caused by one mutation, however sometimes multiple occur at once. The majority of these changes could be negative or even harmful however, a few may have a positive effect on the survival of the species and reproduce with increasing frequency as time passes. Natural selection is a process that can produce the accumulating change over time that leads to a new species.
Many people confuse the concept of evolution with the notion that inherited characteristics can be altered by conscious choice or use and abuse, a concept known as soft inheritance. This is a misunderstanding of the biological processes that lead to evolution. It is more precise to say that evolution is a two-step, independent process that involves the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, which is a group of mammal species that includes chimpanzees and gorillas. The earliest human fossils show that our ancestors were bipeds - walkers on two legs. Genetic and biological similarities show that we have a close relationship with chimpanzees. In actual fact we are the closest connected to chimpanzees belonging to the Pan Genus that includes pygmy and bonobos and pygmy chimpanzees. The last common human ancestor and chimpanzees was between 8 and 6 million years ago.
Humans have developed a range of traits throughout time such as bipedalism, use of fire, and the development of advanced tools. But it's only in the last 100,000 years or so that most of the important traits that distinguish us from other species have emerged. These include a large brain that is complex human ability to create and use tools, and the diversity of our culture.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their environment. This adaptation is driven by natural selection, a process that determines certain traits are preferred over others. The ones who are better adjusted are more likely to pass on their genes to the next generation. This is the process that evolves all species and is the basis of the theory of evolution.
Scientists call this the "law of natural selection." The law states species that have a common ancestor are likely to develop similar traits in the course of time. It is because these traits help them to live and reproduce in their environment.
All organisms possess a DNA molecule that contains the information needed to control their growth. The DNA molecule consists of base pairs that are arranged in a spiral around phosphate molecules and sugar molecules. The sequence of bases within each strand determines the phenotype - the distinctive appearance and behavior of a person. Variations in changes and reshuffling of genetic material (known as alleles) during sexual reproduction cause variation in a population.
Fossils of the first human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. Although there are some differences they all support the idea that modern humans first came into existence in Africa. Evidence from fossils and genetics suggest that early humans migrated from Africa into Asia and then Europe.