The Berkeley Evolution Site
Teachers and students who browse the Berkeley site will find resources to assist them in understanding and teaching evolution. The materials are organized into optional learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains how in time, creatures better able to adapt biologically to changing environments do better than those that are not extinct. Science is all about this process of biological evolution.
What is Evolution?
The word evolution has many nonscientific meanings, such as "progress" or "descent with modification." It is a scientific term that refers to the process of change of characteristics over time in organisms or species. In terms of biology, this change is due to natural selection and genetic drift.
Evolution is one of the fundamental tenets of modern biology. It is an established theory that has withstood the test of time and thousands of scientific tests. Unlike many other scientific theories, such as the Copernican theory or the germ theory of disease, the evolution theory does not address issues of religion or the existence of God.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a step-like fashion over time. 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 presented his theory of evolution in his book On the Origin of Species, written in the early 1800s. It asserts that all species of organisms have an ancestry that can be traced using fossils and other evidence. This is the current view on evolution, and is supported by a variety of scientific fields that include molecular biology.
While scientists do not know exactly how organisms developed however they are sure that the evolution of life on earth is the result of natural selection and genetic drift. People with traits that are advantageous are more likely to live and reproduce, and these individuals pass their genes on to the next generation. Over time this leads to a gradual accumulation of changes to the gene pool that gradually create new species and forms.
Some scientists also employ the term"evolution" to refer to large-scale changes in evolutionary processes like the creation of an entirely new species from an ancestral species. Some scientists, like population geneticists, define the term "evolution" in a more broad sense by referring to the net change in allele frequency over generations. Both definitions are valid and reliable however, some scientists claim that the allele-frequency definition omits crucial aspects of the evolutionary process.
Origins of Life
The most important step in evolution is the development of life. The beginning of life takes place when living systems begin to evolve at a micro scale, for instance within cells.
The origins of life are one of the major topics in various disciplines such as geology, chemistry, biology and chemistry. The question of how living things started is of particular importance in science because it is a major challenge to the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis."
Traditionally, the belief that life can arise 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 development of life to occur by an entirely natural process.
Many scientists still believe that it is possible to transition from nonliving substances to living. However, the conditions required are extremely difficult to replicate in labs. 에볼루션 카지노 사이트 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.
In addition, the development of life depends on the sequence of extremely complex chemical reactions that can't be predicted from basic physical laws on their own. These include the reading and replication of complex molecules, like DNA or RNA, to create proteins that perform a specific function. These chemical reactions are often compared with the chicken-and-egg dilemma of how life began with the emergence of DNA/RNA and protein-based cell machinery is essential for the beginning of life, but without the development of life the chemical process that allows it is not working.
Abiogenesis research requires collaboration among scientists from different fields. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
Today, the word evolution is used to describe the general changes in genetic traits 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 natural selection.
This is a process that increases the frequency of those genes in a species that offer a survival advantage over others, resulting in gradual changes in the appearance of a population. The specific mechanisms responsible for these evolutionary changes are mutation, reshuffling of genes during sexual reproduction, and also gene flow between populations.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo changes and reshuffles in their genes. As mentioned above, those who possess the desirable trait have a higher reproductive rate than those that do not. Over the course of many generations, this difference in the number of offspring born can result in a gradual shift in the average number of advantageous characteristics in a particular population.
An excellent example is the increase in beak size on various species of finches found on the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new habitat. These changes in shape and form could also help create new organisms.
The majority of changes are caused by one mutation, but sometimes several occur at once. Most of these changes can be harmful or neutral however, a few could have a positive impact on survival and reproduce and increase their frequency over time. Natural selection is a mechanism that can produce the accumulating change over time that leads to a new species.
Some people confuse the idea of evolution with the idea that the traits inherited from parents can be changed through conscious choice or use and abuse, which is called soft inheritance. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that lead to it. It is more accurate to say that the process of evolution is a two-step, independent process, which involves the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates - a species of mammals that includes chimpanzees, gorillas, and bonobos. Our predecessors walked on two legs, as demonstrated by the oldest fossils. Genetic and biological similarities suggest that we share a close relationship with the chimpanzees. In reality our closest relatives are the chimpanzees of the Pan genus. This includes pygmy as well as bonobos. The last common ancestor of modern humans and chimpanzees dated 8 to 6 million years old.
Humans have developed a range of traits throughout time including bipedalism, the use of fire, and the development of advanced tools. It is only within the last 100,000 years that we have developed the majority of our essential traits. They include a huge, complex brain human ability to create and use tools, and cultural diversity.
The process of evolution occurs when genetic changes enable members of a group to better adapt to their environment. This adaptation is triggered by natural selection, a process that determines certain traits are preferred over others. The more adjusted are more likely to pass on their genes to the next generation. This is how all species evolve and the foundation for the theory of evolution.
Scientists call this the "law of natural selection." The law states that species that have a common ancestor are more likely to develop similar traits over time. This is because those traits make it easier for them to survive and reproduce in their environment.
All organisms have DNA molecules, which provides the information necessary to guide their growth and development. The DNA structure is composed of base pairs arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each string determines the phenotype or the distinctive appearance and behavior of an individual. Variations in a population can be caused by mutations and reshufflings of genetic material (known collectively as alleles).
Fossils from the first human species, Homo erectus, as well as Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite a few differences in their appearance all support the idea of modern humans' origins in Africa. The fossil evidence and genetic evidence suggest that early humans came out of Africa into Asia and then Europe.