The Berkeley Evolution Site
Teachers and students who browse the Berkeley site will find resources to assist them in understanding and teaching evolution. The resources are organized into a variety of learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains that over time, animals that are more adaptable to changing environments do better than those that are not extinct. Science is about this process of biological evolutionary change.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings. For instance "progress" or "descent with modification." It is a scientific term that is used to describe the process of changing characteristics over time in organisms or species. In terms of biology, this change is caused by natural selection and genetic drift.
Evolution is the central tenet of modern biology. It is a theory that has been tested and 에볼루션카지노 (Evolutionkr.kr) proven through thousands of scientific tests. Evolution does not deal with the existence of God or religious beliefs in the same way as 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 characteristics 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.
In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It asserts that different species of organisms share an ancestry that can be traced through fossils and other evidence. This is the current view of evolution, which is supported in a wide range of scientific fields that include molecular biology.
While scientists do not know exactly how organisms developed, they are confident that the evolution of life on earth is a result of natural selection and genetic drift. People with advantages are more likely to live and reproduce. They transmit their genes on to the next generation. Over time, the gene pool gradually changes and evolves into new species.
Certain scientists also use the term evolution to refer to large-scale changes in evolutionary processes, such as the formation of a new species from an ancestral species. Other scientists, like population geneticists, define it more broadly by referring to an overall variation in the frequency of alleles over generations. Both definitions are valid and acceptable, however some scientists believe that allele-frequency definitions omit important features of evolution.
Origins of Life
The birth of life is a key step in evolution. This occurs when living systems begin to evolve at the micro level - within cells, for instance.
The origins of life are an important subject in a variety of fields that include biology and the field of chemistry. The question of how living things got their start is a major topic in science due to it being an important challenge to the theory of evolution. It is often called "the mystery of life" or "abiogenesis."
Traditionally, the idea that life can emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a common belief before Louis Pasteur's experiments showed that it was impossible for the emergence of life to happen through the natural process.
Many scientists still think it is possible to move from nonliving to living substances. However, the conditions required are extremely difficult to reproduce in the laboratory. Researchers who are interested in the origins and evolution of life are also eager to understand the physical properties of the early Earth as well as other planets.
Additionally, the evolution of life is a sequence of very complex chemical reactions that can't be predicted from the fundamental physical laws on their own. These include the reading and re-reading of complex molecules, such as DNA or RNA, in order to make proteins that perform a specific function. These chemical reactions can be compared with the chicken-and-egg problem: the emergence and development of DNA/RNA, protein-based cell machinery, is necessary for the beginning of life. But without life, the chemistry that is required to make it possible is working.
Research in the field of abiogenesis requires cooperation among scientists from many different disciplines. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
Today, the word evolution is used to describe general changes in genetic traits over time. These changes could result from adaptation to environmental pressures as explained in the article on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This is a process that increases the frequency of genes that confer a survival advantage over others which results in gradual changes in the appearance of a particular population. 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 in their genes. As noted above, individuals who possess the desirable characteristic have a higher reproduction rate than those who do not. This difference in the number of offspring produced over many generations can result in a gradual change in the average number of beneficial traits in a group.
An excellent example is the increase in beak size on various species of finches in the Galapagos Islands, which have developed beaks with different shapes that allow them to easily access food in their new home. These changes in the shape and appearance of organisms could also help create new species.
The majority of the changes that occur are caused by a single mutation, but occasionally, multiple mutations occur at the same time. Most of these changes can be harmful or neutral, but a small number may have a positive effect on survival and reproduce and increase their frequency over time. Natural selection is a process that could result in the accumulation of change over time that eventually leads to a new species.
Some people confuse the notion of evolution with the idea that the traits inherited from parents can be changed through conscious choice, or through use and abuse, a concept called soft inheritance. This is a misinterpretation of the biological processes that lead to the process of evolution. It is more accurate to say that the process of evolution is a two-step, separate process, which involves the forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a species of mammal species which includes chimpanzees as well as gorillas. Our ancestors walked on two legs, as demonstrated by the first fossils. Genetic and biological similarities show that we share a close relationship with the chimpanzees. In fact our closest relatives are the chimpanzees from the Pan genus. This includes pygmy and bonobos. The last common human ancestor and chimpanzees was born between 8 and 6 million years ago.
Humans have evolved a wide range of traits over time including bipedalism, the use of fire and advanced tools. But it's only in the past 100,000 years or so that most of the traits that distinguish us from other species have been developed. These include language, a large brain, the capacity to construct and use sophisticated tools, and a the ability to adapt to cultural differences.
Evolution occurs when genetic changes enable members of an organization to better adapt to their environment. Natural selection is the mechanism that drives this adaptation. Certain traits are preferred over others. The more adjusted are more likely to pass on their genes to the next generation. This is the way all species evolve, and the foundation for the theory of evolution.
Scientists call it the "law of natural selection." The law states that species that have a common ancestor are more likely to develop similar characteristics over time. This is because those traits allow them to survive and reproduce in their natural environment.
Every living thing has an molecule called DNA that holds the information needed to control their growth. The DNA molecule is composed of base pairs arranged spirally around phosphate molecules and sugar molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. Variations 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. Although there are some differences, these fossils all support the idea that modern humans first came into existence in Africa. The fossil evidence and genetic evidence suggest that early humans moved from Africa into Asia and then Europe.