The Berkeley Evolution Site
The Berkeley site contains resources that can help students and teachers understand and teach evolution. The materials are organized in optional learning paths like "What does T. rex look like?"
Charles Darwin's theory on natural selection explains how creatures that are better equipped to adapt biologically to changing environments survive longer and those that do not disappear. Science is concerned with this process of evolutionary change.
What is Evolution?
The term "evolution" can have many nonscientific meanings, including "progress" or "descent with modification." It is scientifically based and refers to the process of change of characteristics in a species or species. This change is based in biological terms on natural selection and drift.
Evolution is an important tenet in modern biology. It is a concept that has been tested and verified by thousands of scientific tests. Unlike many other scientific theories such as the Copernican theory or the germ theory of disease, evolution does not address questions of religion or the existence of God.
Early evolutionists, such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to change in a gradual manner over time. They referred to this as the "Ladder of Nature" or scala naturae. Charles Lyell used the term to describe this concept in his Principles of Geology, first published in 1833.
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 a common ancestry which can be traced through fossils and other evidence. This is the modern view on evolution, which is supported in many disciplines which include molecular biology.
Although scientists aren't able to determine the exact mechanism by which organisms evolved but they are certain that the evolution of life on earth is the result of natural selection and genetic drift. People with desirable traits are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. In time, this results in an accumulation of changes in the gene pool, which eventually create new species and forms.
Certain scientists also use the term evolution to refer to large-scale evolutionary changes such as the creation of a new species from an ancestral species. Some scientists, like population geneticists, define the term "evolution" in a more broad sense by referring to the net variation in the frequency of alleles over generations. Both definitions are correct and palatable, but some scientists argue that allele-frequency definitions do not include important aspects of evolutionary process.
Origins of Life
A key step in evolution is the appearance of life. This occurs when living systems begin to evolve at a micro-level - within individual cells, for example.
The origins of life are an important topic in many areas that include biology and chemistry. The nature of life is a subject of great interest in science because it challenges the theory of evolution. It is sometimes referred to as "the mystery" of life or "abiogenesis."
The notion that life could be born from non-living things was called "spontaneous generation" or "spontaneous evolutionary". This was a popular belief prior to Louis Pasteur's tests proved that the development of living organisms was not possible by a natural process.
Many scientists still think it is possible to go from nonliving to living substances. However, the conditions that are required are extremely difficult to reproduce in the laboratory. Researchers who are interested in the evolution and origins of life are also keen to know the physical properties of the early Earth as well as other planets.
Additionally, the evolution of life depends on the sequence of extremely complex chemical reactions that cannot be predicted based on basic physical laws alone. This includes the conversion of long, information-rich molecules (DNA or RNA) into proteins that perform a function, and the replication of these intricate molecules to create new DNA or RNA sequences. These chemical reactions are often compared to the chicken-and-egg dilemma of how life came into existence: The development of DNA/RNA as well as proteins-based cell machinery is vital for the onset of life, but without the development of life the chemical reaction that is the basis for it isn't working.
Research in the field of abiogenesis requires collaboration among scientists from various fields. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
The term "evolution" is used to describe gradual changes in genetic traits over time. These changes could result from adaptation to environmental pressures, as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This is a method that increases the frequency of those genes in a species that offer an advantage in survival over others, resulting in a gradual change in the appearance of a population. The specific mechanisms behind these changes in evolutionary process include mutation, reshuffling of genes during sexual reproduction, and also gene flow between populations.
While reshuffling and mutation of genes occur in all organisms, the process by which beneficial mutations are more prevalent is known as natural selection. As noted above, individuals who possess the desirable trait have a higher reproduction rate than those who don't. This difference in the number of offspring born over a long period of time can result in a gradual change in the number of advantageous characteristics in a group.
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 that they can eat more easily in their new environment. These changes in form and shape can also aid in the creation of new species.
에볼루션코리아 of changes are caused by a single mutation, however sometimes multiple occur simultaneously. Most of these changes may be neutral or even harmful, but a small number can have a beneficial impact on the survival of the species and reproduce with increasing frequency over time. This is the way of natural selection and it is able to be a time-consuming process that produces the gradual changes that ultimately lead to an entirely new species.
Some people confuse evolution with the idea of soft inheritance that is the belief that inherited traits can be changed through conscious choice or abuse. This is a misinterpretation of the biological processes that lead up to the process of evolution. It is more accurate to say that the process of evolution is a two-step, independent process, which involves the forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates, a group of mammals that includes gorillas, chimpanzees, and bonobos. Our ancestors walked on two legs, as evidenced by the oldest fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In reality, our closest relatives are chimpanzees of the Pan genus. This includes pygmy and bonobos. The last common ancestor of modern humans and chimpanzees dated between 8 and 6 million years old.
In the course of time, humans have developed a range of traits, including bipedalism and the use fire. They also developed advanced tools. But it's only in the past 100,000 years or so that most of the essential characteristics that differentiate us from other species have emerged. These include a big, complex brain, the ability of humans to construct and use tools, and the diversity of our culture.
Evolution occurs when genetic changes allow members of an organization to better adapt to the environment. Natural selection is the mechanism that triggers this adaptation. Certain traits are preferred over others. People with better adaptations are more likely to pass their genes to the next generation. This is how all species evolve and is the basis of the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states species that share an ancestor will tend to develop similar traits over time. This is because these traits help them to survive and reproduce within their environment.
Every living thing has the DNA molecule, which contains the information necessary to direct their growth. The DNA structure is composed of base pairs that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each strand determines 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 early human species Homo erectus, as well as Homo neanderthalensis have been discovered in Africa, Asia and Europe. Although there are some differences the fossils all support the notion that modern humans first came into existence in Africa. Genetic and fossil evidence also suggest that early humans moved from Africa into Asia and then Europe.