The Berkeley Evolution Site
Teachers and students who browse the Berkeley site will find resources to assist them in understanding and teaching evolution. The materials are organized in various learning paths that can be used in a variety of ways for example "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 who do not become extinct. This process of biological evolution is the main focus of science.
What is Evolution?
The word evolution has many nonscientific meanings, such as "progress" or "descent with modification." It is a scientific term that refers to the process of changing traits over time in organisms or species. This change is based in biological terms on natural drift and selection.
Evolution is an important concept in modern biology. It is a concept that has been tested and confirmed through thousands of scientific tests. Unlike many other scientific theories such as the Copernican theory or the germ theory of disease, evolution is not a discussion of spiritual belief 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. They called this the "Ladder of Nature" or scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
Darwin revealed his theory of evolution in his book On the Origin of Species, written in the early 1800s. It claims that different species of organisms share an ancestry that can be traced through fossils and other lines of evidence. This is the current perspective on evolution, which is supported by a variety of areas of science which include molecular biology.
Although scientists aren't able to determine exactly how 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 transmit their genes to the next generation. As time passes, this results in a gradual accumulation of changes to the gene pool which gradually create new species and forms.
Some scientists also employ the term"evolution" to describe large-scale evolutionary changes, such as the formation of an entirely new species from an ancestral species. Others, like population geneticists, define evolution more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are valid and acceptable, however some scientists believe that allele-frequency definitions omit important features of evolution.
Origins of Life
The birth of life is an essential stage in evolution. The emergence of life happens when living systems begin to develop at a microscopic scale, for instance within cells.
The origin of life is an important topic in many fields such as biology and the field of chemistry. The nature of life is a topic of interest in science, as it challenges the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis."
Traditionally, the idea that life can arise from nonliving things is known as spontaneous generation or "spontaneous evolution." This was a common belief before Louis Pasteur's research showed that it was impossible for the emergence of life to happen through the natural process.
Many scientists still believe that it is possible to make the transition from nonliving substances to life. However, the conditions required are extremely difficult to reproduce in the laboratory. Researchers interested in the origins and development of life are also eager to understand the physical properties of the early Earth as well as other planets.
The life-cycle of a living organism is dependent on a number of complex chemical reactions, that are not predicted by the basic physical laws. These include the reading and replication of complex molecules, such as DNA or RNA, to produce proteins that serve a specific function. These chemical reactions are often compared to the chicken-and-egg problem of how life first appeared with the appearance of DNA/RNA and proteins-based cell machinery is vital for the beginning of life, but without the development of life the chemistry that makes it possible does not appear to work.
Abiogenesis research requires collaboration among researchers from different disciplines. This includes prebiotic scientists, astrobiologists, and planet scientists.
Evolutionary Changes
The term "evolution" is used to describe the cumulative changes in genetic characteristics over time. These changes may result from adaptation to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
This mechanism also increases the number of genes that provide the advantage of survival for a species, resulting in an overall change in the appearance of a group. These evolutionary changes are triggered by mutations, reshuffling of genes in the process of sexual reproduction, and also by gene flow.
While reshuffling and mutation of genes occur in all living organisms and the process by which beneficial mutations are more prevalent is called natural selection. As previously mentioned, those who have the advantageous trait have a higher reproductive rate than those who do not. Over many generations, this variation in the number of offspring born can result in a gradual shift in the number of beneficial traits within a group of.
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 the shape and appearance of organisms can also be a catalyst for the creation of new species.
The majority of the changes that take place are the result of one mutation, but occasionally several will happen at once. The majority of these changes are neutral or even harmful to the organism, however a small portion of them could have an advantageous impact on survival and reproduction, thus increasing their frequency in the population over time. This is the way of natural selection and it can, over time, produce the gradual changes that eventually lead to an entirely new species.
Some people confuse the idea of evolution with the notion that the traits inherited from parents can be changed through conscious choice or by use and abuse, a notion known as soft inheritance. This is a misunderstood understanding of the nature of evolution, and of the actual biological processes that cause it. A more precise description is that evolution is a two-step process involving the independent and often antagonistic forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species that includes chimpanzees as well as gorillas. Our predecessors walked on two legs, as demonstrated by the first fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In fact our closest relatives are chimpanzees of the Pan genus. This includes pygmy and bonobos. The last common ancestor of modern humans and chimpanzees lived between 8 and 6 million years ago.
Humans have evolved a wide range of characteristics over time including bipedalism, the use of fire, and the development of advanced tools. It's only within the last 100,000 years that we have developed the majority of our key traits. They include a huge brain that is complex human ability to create and use tools, as well as cultural diversity.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their environment. Natural selection is the process that triggers this adaptation. Certain characteristics are more desirable than others. The more adaptable are more likely to pass on their genes to the next generation. This is the way that all species evolve and is the foundation of the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species which have an ancestor in common will tend to develop similar traits as time passes. This is because these traits make it easier for them to live and reproduce in their environments.
All organisms have DNA molecules, which is the source of information that helps control their growth and development. The DNA molecule is composed of base pairs arranged spirally around phosphate molecules 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 mutations and reshufflings of genetic material (known collectively as alleles).
Fossils from the early human species Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite some differences in their appearance, all support the theory that modern humans' ancestors originated in Africa. 에볼루션 코리아 and fossil evidence also suggest that early humans migrated out of Africa into Asia and then Europe.