The Berkeley Evolution Site
The Berkeley site contains resources that can help students and educators understand and teach evolution. The materials are arranged in various learning paths that can be used in a variety of ways like "What does T. rex look like?"
Charles Darwin's theory of natural selection describes how species who are better equipped to adapt to changes in their environments over time, and those that don't disappear. This process of evolution is the basis of science.
What is Evolution?
The word evolution can have many nonscientific meanings. For example it could mean "progress" and "descent with modifications." Scientifically, it refers to a change in the characteristics of living things (or species) over time. In terms of biology this change is due to natural selection and genetic drift.
Evolution is an important principle in modern biology. It is a concept that has been tested and verified by thousands of scientific tests. Contrary to other theories of science like the Copernican theory or the germ theory of disease, evolution does not address questions of religious belief or the existence of God.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical characteristics were predetermined to change, in a step-wise manner, over time. 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.
에볼루션코리아 revealed his theory of evolution in his book On the Origin of Species, written in the early 1800s. It asserts that different species of organisms have a common ancestry, which can be proven through fossils and other evidence. This is the modern view of evolution that is supported by many research lines in science which includes molecular genetics.
Although scientists aren't able to determine exactly how organisms evolved however they are sure that the evolution of life on earth is the result of natural selection and genetic drift. Individuals with advantageous traits are more likely to survive and reproduce, and they transmit their genes to the next generation. As time passes the gene pool gradually changes and develops into new species.
Certain scientists use the term evolution in reference to large-scale changes, like the formation of a species from an ancestral one. Others, like population geneticists, define the term "evolution" more broadly by referring to an overall change in the frequency of alleles across generations. Both definitions are valid and palatable, but certain scientists argue that allele frequency definitions do not include important aspects of evolutionary process.
Origins of Life
A key step in evolution is the development of life. This occurs when living systems begin to develop at the micro level, within cells, for instance.
The origins of life are an important issue in many fields that include biology and chemical. The question of how living things got their start is of particular importance in science since it poses an important challenge to the theory of evolution. It is sometimes referred to as "the mystery" of life or "abiogenesis."
Traditionally, the idea that life can emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a popular view before Louis Pasteur's research showed that it was impossible for the creation of life to happen through an entirely natural process.
Many scientists believe that it is possible to go from nonliving substances to living. The conditions needed to make life are not easy to reproduce in a lab. Researchers studying the beginnings of life are also keen to understand the physical properties of early Earth and other planets.
The development of life is dependent on a number of complex chemical reactions, which are not predicted by basic physical laws. These include the reading of long information-rich molecules (DNA or RNA) into proteins that carry out some function as well as the replication of these complex molecules to produce new DNA or sequences of RNA. These chemical reactions are often compared to the chicken-and-egg problem of how life first appeared: The emergence of DNA/RNA and protein-based cell machinery is essential for the onset of life, however, without the emergence of life the chemical reaction that is the basis for it is not working.
Abiogenesis research requires collaboration between researchers from different fields. This includes prebiotic chemists, planet scientists, astrobiologists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used today to refer to the accumulated changes in the genetic characteristics of an entire 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 number of genes that provide the advantage of survival for an animal, resulting in an overall change in the appearance of the group. These evolutionary changes are caused by mutations, reshuffling of genes during sexual reproduction and gene flow.
Natural selection is the process that makes beneficial mutations more frequent. All organisms undergo mutations and reshuffles of genes. This occurs because, as we've mentioned earlier, those individuals with the beneficial trait tend to have a higher reproduction rate than those with it. Over many generations, this difference in the numbers of offspring born can result in a gradual shift in the average number of beneficial characteristics in a particular population.
An excellent example is the increase in beak size on different species of finches found on the Galapagos Islands, which have developed beaks with different shapes that allow them to easily access food in their new habitat. These changes in the shape and appearance of organisms could also aid in the creation of new species.
The majority of changes are caused by a single mutation, although sometimes multiple occur simultaneously. The majority of these changes could be negative or even harmful however, a few can have a beneficial impact on the survival of the species and reproduce, increasing their frequency over time. Natural selection is a mechanism that causes the accumulating change over time that eventually leads to a new species.
Some people confuse the notion of evolution with the notion that the traits inherited from parents can be altered by conscious choice, or through use and abuse, a concept called soft inheritance. This is a misunderstood understanding of the nature of evolution, and of the actual biological processes that lead to it. A more accurate description of evolution is that it 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 species of mammal species that includes gorillas and chimpanzees. Our ancestors walked on two legs, as evidenced by the first fossils. Biological and genetic similarities indicate that we share a close relationship with chimpanzees. In reality, we are most closely related to the chimpanzees within the Pan genus, which includes bonobos and pygmy chimpanzees. The last common ancestor shared between modern humans and chimpanzees was between 8 and 6 million years old.
Over time, humans have developed a number of traits, including bipedalism as well as the use of fire. They also invented advanced tools. However, it is only in the past 100,000 years or so that the majority of the traits that distinguish us from other species have developed. They include language, a large brain, the capacity to create and utilize complex tools, as well as the diversity of our culture.
Evolution happens when genetic changes allow individuals in a group to better adapt to their surroundings. 에볼루션코리아 is the mechanism that drives 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 is the basis of the theory of evolution.
Scientists refer to it as the "law of natural selection." The law states that species that have a common ancestor are more likely to develop similar characteristics over time. This is because these traits help them to live and reproduce in their environment.
Every living thing has a DNA molecule that is the source of information that helps guide their growth and development. The structure of DNA is made of base pairs arranged in a spiral around phosphate and sugar 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 reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the earliest human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. These fossils, despite some variations in their appearance, all support the hypothesis that modern humans' ancestors originated in Africa. The fossil evidence and genetic evidence suggest that early humans came from Africa into Asia and then Europe.