The Berkeley Evolution Site
Students and teachers who explore the Berkeley site will find resources to assist them in understanding and teaching evolution. The materials are organized into optional learning paths like "What did T. rex taste like?"
Charles Darwin's theory of natural selection describes how species who are better able to adapt biologically to changing environments over time, and those who do not disappear. This process of evolution in biology is the main focus of science.
What is Evolution?
The term "evolution" could be used to refer to a variety of nonscientific meanings. For instance it could refer to "progress" and "descent with modifications." Scientifically it refers to a changing the characteristics of organisms (or species) over time. In biological terms the change is caused by natural selection and genetic drift.
Evolution is an important tenet in the field of biology today. It is an established theory that has stood the test of time and thousands of scientific tests. Unlike many other scientific theories, such as the Copernican theory or the germ theory of disease, the evolution theory is not a discussion of spiritual belief or 에볼루션 코리아 the existence of God.
Early evolutionists like 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 called this the "Ladder of Nature" or the scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
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 using fossils and 에볼루션 바카라사이트 other evidence. This is the current understanding of evolution, which is supported by numerous research lines in science which includes molecular genetics.
While scientists do not know exactly how organisms evolved, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. People with desirable traits are more likely to live and reproduce. They pass on their genes on to the next generation. Over time this leads to gradual changes in the gene pool, which eventually result in new species and types.
Some scientists also employ the term"evolution" to refer to large-scale evolutionary changes like the creation of a new species from an ancestral species. Other scientists, like population geneticists, define the term "evolution" more broadly, referring to an overall change in the frequency of alleles across generations. Both definitions are valid and palatable, but some scientists argue that allele-frequency definitions do not include important aspects of evolution.
Origins of Life
The birth of life is an essential step in the process of evolution. This occurs 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, including biology, chemistry and geology. The question of how living things started is of particular importance in science since it poses an enormous challenge to the theory of evolution. It is often called "the mystery of life," or "abiogenesis."
The notion that life could be born from non-living objects was referred to as "spontaneous generation" or "spontaneous evolutionary". It was a popular belief before Louis Pasteur's tests proved that the emergence of living organisms was not possible through the natural process.
Many scientists still believe it is possible to go from nonliving materials to living. The conditions required to create life are difficult to replicate in a 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.
The growth of life is dependent on a number of complex chemical reactions which cannot be predicted by basic physical laws. These include the reading of long, information-rich molecules (DNA or 에볼루션사이트 RNA) into proteins that carry out some function, and the replication of these intricate molecules to produce new DNA or RNA sequences. These chemical reactions are often compared to the chicken-and-egg problem of how life came into existence: The development of DNA/RNA as well as proteins-based cell machinery is vital to the birth of life, however, without the emergence of life the chemical reaction that is the basis for it isn't working.
Abiogenesis research requires collaboration with researchers from different disciplines. This includes prebiotic scientists, astrobiologists, and planet scientists.
Evolutionary Changes
The word evolution is usually used to refer to the accumulated changes in the genetic characteristics of an entire population over time. These changes may be the result of the adaptation to environmental pressures as explained in Darwinism.
This is a process that increases the frequency of genes that offer an advantage in survival over other species and causes a gradual change in the overall appearance of a particular population. These evolutionary changes are caused by mutations, reshuffling genes in the process of sexual reproduction, and also by the flow of genes.
While reshuffling and mutations of genes occur in all living organisms The process through which beneficial mutations become more common is known as natural selection. As noted above, individuals with the beneficial trait have a higher reproductive rate than those that do not. This differential in the number of offspring born over many generations can cause a gradual change in the average number advantageous traits in the group.
An excellent example is the growth of beak size on different species of finches on the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new habitat. These changes in shape and form could also help create new organisms.
Most of the changes that take place are caused by a single mutation, but occasionally several will happen at the same time. Most of these changes can be neutral or even harmful however, a small percentage could have a positive impact on the survival of the species and reproduce and increase their frequency over time. Natural selection is a process that could result in the accumulation of change over time that eventually leads to a new species.
Some people mistakenly associate evolution with the concept of soft inheritance that is the belief that inherited traits can be changed through conscious choice or abuse. This is a misunderstanding of the nature of evolution and of the actual biological processes that cause it. It is more accurate to say that evolution is a two-step, independent process that involves the forces of natural selection and mutation.
Origins of Humans
Humans today (Homo sapiens) evolved from primates - a group of mammals that includes gorillas, chimpanzees, and bonobos. Our predecessors walked on two legs, as demonstrated by the oldest fossils. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In actual fact, our closest relatives are the chimpanzees from the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor and chimpanzees lived between 8 and 6 million years ago.
As time has passed humans have developed a variety of characteristics, such as bipedalism as well as the use of fire. They also created advanced tools. However, it is only in the past 100,000 years or so that most of the important traits that distinguish us from other species have emerged. These include language, a large brain, the capacity to construct and 에볼루션 바카라 무료 use complex tools, as well as the ability to adapt to cultural differences.
Evolution happens when genetic changes allow individuals of a population to better adapt to their environment. Natural selection is the process that drives this adaptation. Certain traits are preferred over others. The ones who are better adjusted are more likely to pass their genes on to the next generation. This is the way all species evolve, and the foundation for the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species which have a common ancestor are more likely to develop similar characteristics over time. This is because the traits make it easier for them to survive and reproduce in their environments.
Every living thing has a DNA molecule that contains the information needed to control their growth. The DNA molecule consists of base pairs arranged spirally around phosphate molecules and sugar molecules. The sequence of bases within each strand determines the phenotype, or the individual's characteristic appearance and behavior. Variations in changes and reshuffling of genetic material (known as alleles) during sexual reproduction cause variation in a group.
Fossils from the earliest human species Homo erectus and Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite variations in their appearance, all support the theory of the origins of modern humans in Africa. The genetic and fossil evidence suggests that the first humans left Africa and migrated to Asia and 에볼루션 바카라 Europe.