The Berkeley Evolution Site
The Berkeley site has resources that can help students and educators to understand and teach about evolution. The resources are organized into 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 explains how creatures who are better equipped to adapt biologically to changing environments survive longer and those who do not disappear. Science is all about this process of biological evolutionary change.
What is Evolution?
The term "evolution" could be used to refer to a variety of nonscientific meanings. For example it could mean "progress" and "descent with modifications." It is an academic term that is used to describe the process of changing traits over time in organisms or species. This change is based in biological terms on natural selection and drift.
무료에볼루션 is a fundamental principle in the field of biology today. It is a concept that has been tested and confirmed by thousands of scientific tests. It does not address the existence of God or religious beliefs, unlike many other theories of science, such as the Copernican or germ theory of diseases.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a stepped-like manner over time. This was called the "Ladder of Nature", or scala Naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
Darwin published his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It asserts that different species of organisms have a common ancestry, which can be determined through fossils and other lines of evidence. This is the modern view on evolution, and is supported in a wide range of scientific fields, including molecular biology.
While scientists don't know exactly how organisms developed but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. People with advantages are more likely to survive and reproduce. These individuals transmit their genes to the next generation. As time passes the gene pool slowly changes and develops into new species.
Certain scientists use the term"evolution" to refer to large-scale changes, such the development of a species from an ancestral one. Some scientists, like population geneticists, define the term "evolution" in a broad sense, talking about the net change in the frequency of alleles across generations. Both definitions are valid and acceptable, however certain scientists argue that allele frequency definitions miss important aspects of the evolution.
Origins of Life
The birth of life is a key stage in evolution. This happens when living systems begin to develop at a micro-level - within individual cells, for instance.
The origins of life are an issue in a variety of disciplines that include geology, chemistry, biology and chemistry. The origin of life is a subject that is of immense interest to scientists, as it is a challenge to the theory of evolution. It is often described as "the mystery of life" or "abiogenesis."
The idea that life could arise from non-living objects was referred to as "spontaneous generation" or "spontaneous evolutionary". It was a common belief prior to Louis Pasteur's tests proved that the development of living organisms was not possible by the natural process.
Many scientists still think it is possible to go from nonliving substances to living ones. However, the conditions needed are extremely difficult to reproduce in labs. Researchers who are interested in the origins and development of life are also eager to learn about the physical characteristics of the early Earth as well as other planets.
The life-cycle of a living organism is also dependent on a series of complex chemical reactions, which cannot be predicted by basic physical laws. These include the reading and the replication of complex molecules, like DNA or RNA, to produce proteins that perform a particular function. These chemical reactions can be compared with the chicken-and-egg issue: the emergence and development of DNA/RNA, the protein-based cell machinery, is necessary for the onset life. But without life, the chemistry needed to make it possible does appear to work.
Research in the field of abiogenesis requires collaboration among scientists from many different disciplines. This includes prebiotic chemists, the astrobiologists, the planet scientists, geologists and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used today to describe the accumulated changes in genetic characteristics of populations over time. These changes may be the result of adaptation to environmental pressures as described in Darwinism.
This latter mechanism increases the frequency of genes that confer an advantage for survival in the species, leading to an overall change in the appearance of a group. The specific mechanisms that cause these changes in evolutionary process include mutation, reshuffling of genes during sexual reproduction, and also gene flow between populations.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo changes and reshuffles of their genes. As noted above, individuals who possess the desirable characteristic have a higher reproduction rate than those who do not. Over the course of many generations, this differential in the numbers of offspring born can result in gradual changes in the average number of advantageous traits within a group of.
One good example is the growth of the size of the beaks on different species of finches on the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new home. These changes in shape and form could also help create new organisms.
Most of the changes that take place are the result of a single mutation, but occasionally, multiple mutations occur at the same time. Most of these changes can be harmful or neutral however, a small percentage could have a positive impact on survival and reproduction, increasing their frequency over time. Natural selection is a mechanism that could result in the accumulation of change over time that eventually leads to the creation of a new species.
Many people confuse evolution with the idea of soft inheritance which is the notion that traits inherited from parents can be changed through deliberate choice or misuse. This is a misinterpretation of the biological processes that lead to evolution. A more accurate description is that evolution involves 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 chimpanzees as well as gorillas. Our predecessors walked on two legs, as shown by the first fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In fact our closest relatives are the chimpanzees belonging to the Pan genus. This includes pygmy as well as bonobos. The last common ancestor of humans and chimpanzees was 8 to 6 million years old.
Humans have evolved a wide range of traits throughout time such as bipedalism, use of fire and advanced tools. However, it is only in the past 100,000 years or so that the majority of the important traits that distinguish us from other species have developed. They include a huge 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 is when genetic changes allow members of a group to better adapt to the environment. This adaptation is driven by natural selection, a process whereby certain traits are favored over other traits. The ones with the best adaptations are more likely to pass their genes to the next generation. This is the way all species evolve and is the basis for the theory of evolution.
Scientists call this the "law of natural selection." The law states that species which share an ancestor will tend to develop similar characteristics in the course of time. It is because these traits make it easier to survive and reproduce within their environment.
Every organism has an molecule called DNA that holds the information necessary to direct their growth. The DNA molecule is composed of base pairs that are arranged in a spiral around sugar molecules and phosphate molecules. The sequence of bases within each strand determines the phenotype, or the individual's characteristic appearance and behavior. 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 theory of modern humans' origins in Africa. Evidence from fossils and genetics suggest that early humans moved out of Africa into Asia and then Europe.