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 arranged in different learning paths like "What does T. rex look like?"
Charles Darwin's theory of natural selection states that over time creatures that are better able to adapt biologically to changing environments thrive, and those that are not extinct. Science is about the process of biological evolution.
What is Evolution?
The term "evolution" can have many nonscientific meanings, such as "progress" or "descent with modification." Scientifically, it refers to a changes in the traits of organisms (or species) over time. The reason for this change is biological terms on natural drift and selection.
Evolution is one of the fundamental tenets of modern biology. It is a concept that has been verified by a myriad of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, evolution does not address questions of spiritual belief or God's existence.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to change in a step-like fashion over time. They referred to this as the "Ladder of Nature" or the scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
Darwin published his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It asserts that different species of organisms share an ancestry that can be traced through fossils and other evidence. This is the modern view of evolution that is supported by many research lines in science, including molecular genetics.
Scientists don't know the evolution of organisms however they are certain that natural selection and genetic drift are responsible for the development of life. People with desirable traits are more likely to live and reproduce, and they pass their genes on to the next generation. As time passes the gene pool gradually changes and develops into new species.
Some scientists employ the term"evolution" to refer to large-scale changes, like the formation of a species from an ancestral one. Other scientists, such as population geneticists, define the term "evolution" more broadly by referring to the net change in the frequency of alleles across generations. Both definitions are valid and reliable, although some scientists argue that the allele-frequency definition is missing essential aspects of the evolution process.
Origins of Life
A key step in evolution is the emergence of life. The emergence of life occurs when living systems start to develop at a micro level, like within cells.
The origins of life is one of the major topics in various disciplines, including biology, chemistry and geology. The nature of life is a subject of interest in science because it is a challenge to the theory of evolution. It is often described as "the mystery of life" or "abiogenesis."
The idea that life could be born from non-living matter was known as "spontaneous generation" or "spontaneous evolutionary". This was a popular belief prior to Louis Pasteur's experiments proved that the emergence of living organisms was not achievable through the natural process.
Many scientists believe that it is possible to make the transition from nonliving materials to living. However, the conditions that are required are extremely difficult to reproduce in a laboratory. Researchers interested in the origins and development of life are also keen to know the physical properties of the early Earth as well as other planets.
The development of life is also dependent on a series of complex chemical reactions which cannot be predicted by basic physical laws. These include the reading and the replication of complex molecules, such as DNA or RNA, in order to make proteins that perform a particular function. These chemical reactions can be compared with a chicken-and egg problem which is the development and emergence of DNA/RNA, a protein-based cell machinery, is necessary for the onset life. But, without life, the chemistry needed to make it possible is working.
Research in the field of abiogenesis requires collaboration among scientists from many different fields. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
The word evolution is usually used today to describe the accumulated changes in the genetic traits of an entire population over time. These changes can result from adaptation to environmental pressures as explained in the article on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
This process increases the frequency of genes that provide the advantage of survival for the species, leading to an overall change in the appearance of a group. These evolutionary changes are triggered by mutations, reshuffling genes during sexual reproduction, and the flow of genes.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo changes and reshuffles of their genes. As noted above, individuals with the beneficial trait have a higher reproduction rate than those who do not. This variation in the number of offspring born over many generations can result in a gradual shift in the average number advantageous traits within a group.
An excellent example is the growing beak size on various species of finches in the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new home. These changes in shape and form can aid in the creation of new organisms.
Most of the changes that occur are caused by one mutation, but occasionally several will happen at the same time. Most of these changes are neither harmful nor even harmful 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. Natural selection is a process that causes 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 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 accurate to say that evolution is a two-step, independent process, that is influenced by the forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo Sapiens) evolved from primates, a species of mammal species that includes chimpanzees and gorillas. The earliest human fossils prove that our ancestors were bipeds, walking on two legs. Genetic and biological similarities suggest that we are closely related to chimpanzees. In fact, we are most closely connected to chimpanzees belonging to the Pan genus, which includes bonobos and pygmy chimpanzees. The last common ancestor of modern humans and chimpanzees was between 8 and 6 million years ago.
Over time humans have developed a range of characteristics, such as bipedalism and the use fire. They also created 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 emerged. These include language, large brain, the ability to build and use sophisticated tools, and a cultural diversity.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their surroundings. 에볼루션 사이트 is driven by natural selection, a process whereby certain traits are preferred over others. The more adapted are more likely to pass on their genes to the next generation. This is the way that all species evolve, and it is the foundation of the theory of evolution.
Scientists call this the "law of natural selection." The law states species that have an ancestor in common will tend to develop similar characteristics in the course of time. It is because these traits make it easier to live and reproduce in their environment.
Every organism has a DNA molecule that provides the information necessary to guide their growth and development. The DNA structure is made of base pairs arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines the phenotype, or the individual's characteristic appearance and behavior. Variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
무료에볼루션 of 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 hypothesis that modern humans first appeared in Africa. The fossil evidence and genetic evidence suggest that early humans migrated from Africa into Asia and then Europe.