The Berkeley Evolution Site
The Berkeley site offers resources that can help students and teachers to understand and teach about evolution. The materials are organized in different learning paths for example "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how over time creatures that are better able to adapt biologically to changing environments do better than those that don't become extinct. Science is all about the process of biological evolution.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings, including "progress" or "descent with modification." It is scientifically based and refers to the process of changing characteristics in a species or species. This change is based in biological terms on natural selection and drift.
Evolution is a fundamental concept in the field of biology today. It is a well-supported theory that has stood up to the test of time and a multitude of scientific studies. In contrast to other theories in science such as the Copernican theory or the germ theory of disease, the evolution theory is not a discussion 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 gradual 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.
In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It asserts that all species of organisms have an ancestry that can be traced through fossils and other evidence. This is the modern view of evolution, which is supported in a wide range of scientific fields, including molecular biology.
While scientists don't know exactly how organisms evolved but they are certain that the evolution of life on earth is the result of natural selection and genetic drift. People with advantages are more likely to live and reproduce. These individuals then pass their genes to the next generation. Over time, the gene pool gradually changes and evolves into new species.
Some scientists use the term evolution in reference to large-scale changes, like the evolution of an animal from an ancestral one. Others, like population geneticists, define the term "evolution" more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are correct and acceptable, but certain scientists argue that allele frequency definitions miss important aspects of the evolutionary process.
Origins of Life
The birth of life is a key step in evolution. The emergence of life occurs when living systems start to develop at a micro scale, for instance within individual cells.
The origin of life is a topic in many disciplines, including geology, chemistry, biology and chemistry. The nature of life is an area of interest in science, as it is a challenge to the theory of evolution. It is often called "the mystery of life," or "abiogenesis."
The idea that life could arise from non-living things was called "spontaneous generation" or "spontaneous evolutionary". It was a popular belief before Louis Pasteur's tests proved that the creation of living organisms was not possible through an organic process.
Many scientists still think it is possible to go from living to nonliving substances. However, the conditions that are required are extremely difficult to replicate in the laboratory. Researchers who are interested in the origins and evolution of life are also keen to understand the physical properties of the early Earth as well as other planets.
Furthermore, the growth of life depends on the sequence of extremely complex chemical reactions that cannot be predicted from basic physical laws on their own. These include the reading of long information-rich molecules (DNA or RNA) into proteins that perform some function and the replication of these intricate molecules to create new DNA or RNA sequences. These chemical reactions are often compared with the chicken-and-egg issue of how life began: The emergence of DNA/RNA and proteins-based cell machinery is vital for the onset of life, however, without the development of life, the chemical process that allows it is not working.
Research in the field of abiogenesis requires collaboration among scientists from a variety of disciplines. This includes prebiotic chemists, planet scientists, astrobiologists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used to describe the cumulative changes in genetic characteristics of populations 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 process increases the frequency of genes that provide an advantage for survival in the species, leading to an overall change in the appearance of a group. These changes in evolutionary patterns are caused by mutations, reshuffling of genes during sexual reproduction, and the flow of genes.
While reshuffling and mutation of genes occur in all living organisms and the process by which beneficial mutations are more prevalent is known as natural selection. This occurs because, as we've mentioned earlier those who have the beneficial trait tend to have a higher reproduction rate than those without it. This variation in the number of offspring that are produced over many generations can result in a gradual change in the average number of beneficial traits in a group.
One good example is the growing beak size on different species of finches found on the Galapagos Islands, which have developed different beak shapes that allow them to easily access food in their new environment. These changes in shape and form can also help create new organisms.
Most of the changes that take place are the result of one mutation, however occasionally, multiple mutations occur at once. Most of these changes are neither harmful nor even harmful to the organism however, a small proportion of them can have a positive 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 causes the accumulating change over time that leads to the creation of a new species.
Some people mistakenly associate evolution with the concept of soft inheritance, which is the idea that traits inherited from parents can be changed through conscious choice or abuse. This is a misunderstanding of the nature of evolution, and of the actual biological processes that trigger it. A more accurate description is that evolution is a two-step procedure which involves the separate, and often competing, 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. The earliest human fossils indicate that our ancestors were bipeds. They were walkers with two legs. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In fact we are the closest related to the chimpanzees within the Pan genus, which includes pygmy chimpanzees and bonobos. 무료 에볼루션 as well as chimpanzees lived 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 developed advanced tools. But it's only in the last 100,000 years or so that the majority of the essential traits that distinguish us from other species have developed. These include a big brain that is complex, the ability of humans to construct and use tools, as well as the diversity of our culture.
The process of evolution occurs when genetic changes allow members of a population to better adapt to their environment. This adaptation is driven by natural selection, a process that determines certain traits are preferred over other traits. The better adaptable are more likely to pass their genes on to the next generation. This is the way all species evolve and the foundation for the theory of evolution.
Scientists call this the "law of natural selection." The law says that species that have a common ancestor are more likely to develop similar traits over time. This is because these traits make it easier to live and reproduce in their environment.
Every living thing has an molecule called DNA that holds the information needed to guide their growth. The structure of DNA is composed of base pair that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. The variations in a population are 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. Although there are some differences the fossils all support the hypothesis that modern humans first appeared in Africa. The genetic and fossil evidence suggests that the first humans left Africa and migrated to Asia and Europe.