The Berkeley Evolution Site
The Berkeley site offers resources that can help students and educators learn about and teach evolution. The materials are arranged in optional learning paths, such as "What does T. rex look like?"
Charles Darwin's theory of natural selection states that in time, creatures better able to adapt biologically to changing environments survive and those that do not become extinct. Science is concerned with this process of biological evolution.
What is Evolution?
The term "evolution" could have a variety of meanings that are not scientific. For example it could refer to "progress" and "descent with modifications." Scientifically it is a term used to describe a changes in the traits of living things (or species) over time. This change is based in biological terms on natural drift and selection.
Evolution is a key tenet in the field of biology today. It is a concept that has been proven by thousands of scientific tests. Evolution doesn't deal with God's presence or spiritual beliefs like other theories of science, such as the Copernican or germ theory of diseases.
Early evolutionists, including Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change in a step-like manner, as time passes. 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.
Darwin published his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It claims that different species of organisms share the same ancestry, which can be traced through fossils and other evidence. This is the modern view of evolution, and is supported by many research lines in science, including molecular genetics.
While scientists do not know the exact mechanism by which organisms evolved but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. Individuals with advantageous traits are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. As time passes the gene pool gradually changes and evolves into new species.
Certain scientists also use the term"evolution" to describe large-scale evolutionary changes such as the creation of an entirely new species from an ancestral species. Other scientists, like population geneticists, define the term "evolution" more broadly, referring to a net change in the frequency of alleles across generations. Both definitions are accurate and palatable, but some scientists believe that allele-frequency definitions do not include important aspects of evolution.
Origins of Life
The most important step in evolution is the development of life. The beginning of life takes place when living systems begin to develop at a microscopic level, such as within individual cells.
The origins of life are an important issue in a variety of disciplines that include biology and chemical. The question of how living organisms began is a major topic in science because it is an important 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 things was called "spontaneous generation" or "spontaneous evolutionary". This was a popular belief before Louis Pasteur's experiments proved that the development of living organisms was not possible by the natural process.
Many scientists believe it is possible to transition from nonliving to living substances. The conditions required for the creation of life are difficult to reproduce in a lab. Researchers studying the origins of life are also interested in understanding the physical properties of early Earth and other planets.
In addition, the development of life depends on the sequence of extremely complex chemical reactions that cannot be predicted based on basic physical laws alone. 에볼루션 include the transformation of long information-rich molecules (DNA or RNA) into proteins that carry out a function as well as the replication of these complex molecules to create new DNA or sequences of RNA. These chemical reactions can be compared to a chicken-and egg problem: the emergence and development of DNA/RNA, the protein-based cell machinery, is required to begin the process of becoming a living organism. But without life, the chemistry needed to enable it does appear to work.
Abiogenesis research requires collaboration among researchers from different fields. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
Today, the word evolution is used to describe the cumulative changes in genetic characteristics over time. These changes may be the result of adaptation to environmental pressures as explained in Darwinism.
This mechanism also increases the frequency of genes that offer an advantage for survival in the species, leading to an overall change in the appearance of the group. These changes in evolutionary patterns are caused by mutations, reshuffling genes during sexual reproduction and gene flow.
Natural selection is the process that allows beneficial mutations to become more common. 에볼루션코리아 undergo mutations and reshuffles of their genes. This is because, as we've mentioned earlier, those individuals with the beneficial trait tend to have a higher fertility rate than those who do not have it. Over many generations, this differential in the numbers of offspring produced can result in a gradual shift in the average number of advantageous characteristics in a particular population.
This is evident in the evolution of different beak shapes on finches from the Galapagos Islands. They have developed these beaks in order they can get food more easily in their new environment. These changes in shape and form could also aid in the creation of new species.
The majority of changes are caused by a single mutation, however sometimes multiple occur at the same time. Most of these changes may be harmful or neutral, but a small number can have a beneficial impact on survival and reproduce, increasing their frequency over time. This is the mechanism of natural selection, and it is able to, over time, produce the cumulative changes that eventually result in an entirely new species.
Some people confuse evolution with the idea of soft inheritance, which is the idea that traits inherited from parents can be altered by deliberate choice or misuse. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that lead to it. A more precise description is that evolution is a two-step process involving the independent, and often competing, forces of mutation and natural selection.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species that includes gorillas and chimpanzees. The earliest human fossils show that our ancestors were bipeds - walkers with two legs. Genetic and biological similarities show that we have a close relationship with the chimpanzees. In actual fact our closest relatives are the chimpanzees of the Pan genus. This includes pygmy, as well as bonobos. The last common ancestor of modern humans and chimpanzees dated 8 to 6 million years old.
As time has passed, humans have developed a range of characteristics, such as bipedalism and the use of fire. They also created advanced tools. But it's only in the past 100,000 years or so that the majority of the traits that distinguish us from other species have emerged. These include a large brain that is sophisticated human ability to create and use tools, as well as cultural variety.
Evolution occurs when genetic changes allow members of a population to better adapt to their surroundings. Natural selection is the process that triggers this adaptation. Certain characteristics are more desirable than others. The better adapted are more likely to pass their genes on 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 it as the "law of Natural Selection." The law states species that have a common ancestor are likely to develop similar characteristics in the course of time. This is because the characteristics make it easier for them to survive and reproduce in their natural environment.
Every organism has a DNA molecule that is the source of information that helps direct their growth and development. The DNA molecule is composed of base pairs that are spirally arranged around sugar molecules 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 and Homo neanderthalensis have been discovered in Africa, Asia and Europe. While there are some differences between them the fossils all support the idea that modern humans first came into existence in Africa. The evidence from fossils and genetics suggests that the first humans left Africa and migrated to Asia and Europe.