The Berkeley Evolution Site

Students and teachers who explore the Berkeley site will find resources to assist them in understanding and teaching evolution. The materials are organized in various learning paths that can be used in a variety of ways, such as "What does T. rex look like?"

Charles Darwin's theory of natural selection states that over time creatures that are more able to adapt to changing environments survive and those that do not become extinct. This process of evolution is the basis of science.


What is Evolution?

The word evolution can be used to refer to a variety of nonscientific meanings. For example it could mean "progress" and "descent with modifications." 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 due to natural selection and genetic drift.

Evolution is a key tenet in the field of biology today. It is an established theory that has stood the test of time and a multitude of scientific studies. Evolution doesn't deal with spiritual beliefs or God's presence, unlike many other theories in science, like 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 evolve in a stepped-like manner over time. This was referred to as the "Ladder of Nature", or 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, written in the early 1800s. It asserts that all species of organisms have common ancestors that can be traced by fossils and other evidence. This is the modern view of evolution, which is supported in many disciplines that include molecular biology.

Scientists do not know the evolution of organisms however they are certain that natural selection and genetic drift are responsible for the evolution of life. Individuals with advantageous characteristics are more likely to survive and reproduce. These individuals pass on their genes on to the next generation. Over time, the gene pool gradually changes and evolves into new species.

Some scientists also employ the term evolution to describe large-scale evolutionary changes like the creation of the new species from an ancestral species. Other scientists, such as population geneticists, define the term "evolution" more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are valid and reliable however some scientists believe that the definition of allele frequency is lacking important features 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 start to develop at a microscopic level, such as within individual cells.

The origins of life are an important topic in many areas that include biology and the field of chemistry. The origin of life is a subject that is of immense interest to scientists, as it is a challenge to the theory of evolution. It is often referred to as "the mystery of life" or "abiogenesis."

The notion that life could arise from non-living matter was known as "spontaneous generation" or "spontaneous evolutionary". It was a popular belief before Louis Pasteur's tests showed that the development of living organisms was not achievable through the natural process.

Many scientists still believe 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 investigating the nature of life are also interested in understanding the physical properties of the early Earth and other planets.

In addition, the development of life depends on a sequence of very complex chemical reactions that can't be predicted based on basic physical laws alone. These include the reading and re-reading of complex molecules, like DNA or RNA, to create proteins that perform a specific function. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is necessary for the beginning of life. But without life, the chemistry required to make it possible appears to be working.

Research in the area of abiogenesis requires cooperation among scientists from various disciplines. This includes prebiotic chemists, the astrobiologists, the planet scientists geophysicists, geologists, and geophysicists.

Evolutionary Changes

The word evolution is usually used today to refer to the accumulated changes in genetic characteristics of a population over time. These changes could result from adaptation to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.

This mechanism also increases the frequency of genes that provide a survival advantage in a species, resulting in an overall change in the appearance of the group. 에볼루션사이트 behind these changes in evolutionary process include mutation and reshuffling of genes in 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 of their genes. As noted above, individuals who possess the desirable trait have a higher reproductive rate than those who do not. Over the course of many generations, this variation in the numbers of offspring born can result in an inclination towards a shift in the average number of advantageous characteristics in a particular population.

This is evident in the evolution of different beak designs on finches that are found in the Galapagos Islands. They have developed these beaks in order they can get food more quickly in their new home. These changes in the shape and form of organisms can also help create new species.

The majority of the changes that occur are the result of one mutation, but occasionally several will happen at once. Most of these changes are not harmful or even detrimental to the organism, but a small percentage can have an advantageous impact on the survival of the organism and its reproduction, thereby increasing the frequency of these changes in the population over time. Natural selection is a mechanism that could result in the accumulation of change over time that eventually leads to the creation of a new species.

Many people confuse the concept of evolution with the notion that the traits inherited from parents can be altered through conscious choice, or through use and abuse, a notion known as soft inheritance. This is a misunderstanding of the nature of evolution and of the actual biological processes that trigger it. A more accurate description of evolution is that it is a two-step procedure involving the independent, and often competing, forces of natural selection and mutation.

Origins of Humans

Humans of today (Homo Sapiens) evolved from primates, a species of mammal species which includes chimpanzees and gorillas. The earliest human fossils show that our ancestors were bipeds, walkers with two legs. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In reality we are the closest connected to chimpanzees belonging to the Pan Genus which includes pygmy chimpanzees and bonobos. The last common human ancestor and chimpanzees was between 8 and 6 million years ago.

As time has passed humans have developed a variety of traits, including bipedalism and the use of fire. They also invented advanced tools. It is only in the last 100,000 years or so that the majority of the important characteristics that differentiate 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 surroundings. This adaptation is driven by natural selection, a process whereby certain traits are more desirable than others. The ones who are better 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 it the "law of natural selection." The law states that species which have a common ancestor are more likely to develop similar characteristics over time. This is because these traits make it easier to reproduce and survive within their environment.

Every living thing has a DNA molecule that contains the information needed to guide their growth and development. The DNA molecule is made up of base pairs arranged spirally around sugar molecules and phosphate molecules. The sequence of bases in each string determines the phenotype or the distinctive appearance and behavior of an individual. Variations in mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction can cause variation in a group.

Fossils of the first human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. Despite some differences the fossils all support the hypothesis that modern humans first appeared in Africa. Evidence from fossils and genetics suggest that early humans migrated from Africa into Asia and then Europe.