The Berkeley Evolution Site
The Berkeley site offers resources that can help students and educators learn about and teach 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 thrive, and those that are not extinct. This process of evolution in biology is the main focus of science.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings, including "progress" or "descent with modification." Scientifically it refers to a change in the characteristics of living organisms (or species) over time. This change is based in biological terms on natural drift and selection.
Evolution is an important principle in the field of biology today. It is an accepted theory that has stood up to the test of time and a multitude of scientific experiments. Evolution doesn't deal with spiritual beliefs or God's presence in the same way as other theories in science, like the Copernican or germ theory of diseases.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to evolve in a step-like fashion over time. This was called the "Ladder of Nature", or scala Naturae. Charles Lyell used the term to describe this idea in his Principles of Geology, first published in 1833.
Darwin revealed his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It states that all species of organisms have the same ancestry, which can be determined through fossils and other lines of evidence. This is the current view on evolution, which is supported by a variety of disciplines, including molecular biology.
Scientists do not know how organisms have evolved but they are sure that natural selection and genetic drift is responsible for the development of life. People with traits that are advantageous are more likely to survive and reproduce, and they pass their genes on to the next generation. In time, this results in an accumulation of changes to the gene pool, which eventually create new species and types.
Some scientists employ the term"evolution" to refer to large-scale changes, like the development of one species from an ancestral one. Others, like population geneticists, define evolution more broadly by referring to an overall change in allele frequencies over generations. Both definitions are valid and acceptable, but some scientists believe that allele-frequency definitions omit important features of evolutionary process.
Origins of Life
A key step in evolution is the emergence of life. The beginning of life takes place when living systems start to develop at a microscopic level, like within cells.
The origins of life is an issue in a variety of disciplines such as biology, chemistry, and geology. The origin of life is a subject of interest in science, as it challenges the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
Traditionally, the belief that life can arise from nonliving objects is known as spontaneous generation or "spontaneous evolution." This was a common belief before Louis Pasteur's experiments proved that it was impossible for the emergence of life to be a result of an entirely natural process.
Many scientists believe it is possible to move from living to nonliving substances. However, the conditions needed are extremely difficult to reproduce in labs. Researchers who are interested in the origins and evolution of life are also keen to know the physical properties of the early Earth as well as other planets.
In addition, the development of life is an intricate sequence of chemical reactions that can't be predicted from basic physical laws on their own. These include the reading of long information-rich molecules (DNA or RNA) into proteins that carry out some function, and the replication of these intricate molecules to produce new DNA or sequences of RNA. These chemical reactions can be compared to the chicken-and-egg issue which is the development and emergence of DNA/RNA, the protein-based cell machinery, is essential to begin the process of becoming a living organism. Although without life, the chemistry that is required to enable it does appear to work.
에볼루션바카라사이트 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 gradual 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 from natural selection.
This latter mechanism increases the frequency of genes that confer a survival advantage in an animal, resulting in an overall change in the appearance of a group. These evolutionary changes are caused by mutations, reshuffling genes in the process of sexual reproduction, and also by the flow of genes.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo mutations and reshuffles of their genes. This happens because, as mentioned above those with the beneficial trait tend to have a higher reproduction rate than those with it. This difference in the number of offspring produced over a long period of time can result in a gradual shift in the number of advantageous traits in the group.
This is evident in the evolution of different beak designs on finches that are found in the Galapagos Islands. They have created these beaks to ensure that they can eat more easily in their new habitat. These changes in form and shape can aid in the creation of new organisms.
The majority of changes are caused by one mutation, however sometimes multiple occur at the same time. The majority of these changes are neither harmful nor even harmful to the organism, however a small portion of them could have an advantageous impact on 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 changes over time that lead to the creation of a new species.
Some people confuse the idea of evolution with the idea that traits inherited can be altered through conscious choice, or through use and abuse, which is called soft inheritance. This is a misinterpretation of the biological processes that lead to evolution. A more accurate description of evolution is that it is a two-step procedure which involves the separate and often antagonistic forces of mutation and natural selection.
Origins of Humans
Humans today (Homo sapiens) evolved from primates - a species of mammals that includes chimpanzees, gorillas, and bonobos. Our ancestors walked on two legs, as shown by the earliest fossils. Genetic and biological similarities suggest that we are closely related to chimpanzees. In reality, we are most closely with chimpanzees in the Pan genus which includes bonobos and pygmy chimpanzees. The last common ancestor of humans and chimpanzees was between 8 and 6 million years old.
In the course of time humans have developed a range of characteristics, including bipedalism and the use of fire. They also created advanced tools. It is only within the last 100,000 years that we've developed the majority of our key characteristics. These include language, large brain, the capacity to build and use complex tools, as well as the diversity of our culture.
Evolution occurs when genetic changes allow individuals in a group to better adapt to their surroundings. This adaptation is triggered by natural selection, a process whereby certain traits are more desirable than other traits. The ones who are better adaptable are more likely to pass on their genes to the next generation. This is the way that all species evolve, and it is the basis of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states species that share an ancestor will tend to develop similar traits over time. It is because these traits allow them to live and reproduce in their environment.
Every living thing has a DNA molecule that contains the information needed to control their growth. The DNA molecule consists of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases in each strand determines the phenotype - the appearance and behavior of a person. The variations in a population are caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the first human species, Homo erectus, as well as Homo neanderthalensis have been discovered 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 genetic and fossil evidence suggests that early humans left Africa and moved to Asia and Europe.