The Berkeley Evolution Site
The Berkeley site contains resources that can help students and teachers understand and teach evolution. The materials are organized in various learning paths that can be used in a variety of ways, such as "What does T. rex look like?"
Charles Darwin's theory of natural selection states that over time creatures that are more adaptable to changing environments do better than those that are not extinct. Science is all about this process of biological evolutionary change.
What is Evolution?
The term "evolution" can have many nonscientific meanings. For instance "progress" or "descent with modification." It is an academic term that refers to the process of change of traits over time in organisms or species. 에볼루션 바카라 for this change is biological terms on natural selection and drift.
Evolution is an important concept in modern biology. It is a theory that has been verified by a myriad of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, evolution does not address questions of religious belief or God's existence.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve 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 states that all species of organisms share common ancestors that can be traced by fossils and other evidence. This is the current perspective on evolution, which is supported in a wide range of disciplines that include molecular biology.
Scientists don't know how organisms have evolved, but they are confident that natural selection and genetic drift is responsible for the evolution of life. People with traits that are advantageous are more likely to survive and reproduce, and they pass their genes on to the next generation. As time passes this leads to gradual changes to the gene pool which gradually lead to new species and forms.
Some scientists use the term"evolution" in reference to large-scale changes, such the development of an animal from an ancestral one. Other scientists, such as population geneticists, define evolution more broadly by referring to a net change in the frequency of alleles across generations. Both definitions are acceptable and accurate however some scientists believe that the definition of allele frequency is lacking crucial aspects of the evolutionary process.
Origins of Life
The development of life is an essential stage in evolution. This happens when living systems begin to develop at the micro level, within individual cells, for instance.
The origin of life is an important topic in many fields, including biology and chemistry. The question of how living organisms began 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."
Traditionally, the idea that life could emerge from nonliving things is known as spontaneous generation or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the development of life to happen through a purely natural process.
Many scientists still believe that it is possible to go from nonliving substances to life. However, the conditions that are required are extremely difficult to replicate in labs. This is why researchers investigating the nature of life are also keen to understand the physical properties of the early Earth and other planets.
Furthermore, the growth of life is dependent on the sequence of extremely complex chemical reactions that can't be predicted from basic physical laws on their own. This includes the conversion of long, information-rich molecules (DNA or RNA) into proteins that carry out a function as well as the replication of these intricate molecules to generate new DNA or RNA sequences. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is necessary to begin the process of becoming a living organism. However without life, the chemistry that is required to create it does appear to work.
Abiogenesis research requires collaboration among scientists from different disciplines. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
Today, the word evolution is used to describe gradual changes in genetic traits over time. These changes can result from the response to environmental pressures as discussed in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
This process increases the frequency of genes that confer the advantage of survival for an animal, resulting in an overall change in the appearance of a group. The specific mechanisms responsible for these evolutionary changes are mutation and reshuffling of genes in sexual reproduction, as well as gene flow between populations.
While mutation and reshuffling of genes are common in all organisms, the process by which beneficial mutations are more frequent is called natural selection. This happens because, as we've mentioned earlier those who have the beneficial trait tend to have a higher fertility rate than those with it. This differential in the number of offspring born over a long period of time can result in a gradual shift in the average number advantageous traits within a group.
This is evident in the evolution of different beak shapes for finches from the Galapagos Islands. They have developed these beaks in order they can get food more quickly in their new home. These changes in form and shape can aid in the creation of new organisms.
The majority of changes are caused by a single mutation, although sometimes multiple occur simultaneously. The majority of these changes are not harmful or even harmful to the organism however a small portion of them could be beneficial to the survival of the organism and its reproduction, thereby increasing the frequency of these changes in the population over time. Natural selection is a mechanism that could result in the accumulation of change over time that eventually leads to a new species.
Some people confuse the idea of evolution with the notion that inherited characteristics can be changed through conscious choice or use and abuse, which is known as soft inheritance. This is a misunderstanding of the nature of evolution and of the actual biological processes that lead to it. 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 mammal species which includes chimpanzees as well as gorillas. The earliest human fossils indicate that our ancestors were bipeds. They were walkers with two legs. Genetic and biological similarities show that we share a close relationship with the chimpanzees. In reality our closest relatives are the chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor and chimpanzees was between 8 and 6 million years ago.
Humans have evolved a wide range of traits throughout time, including bipedalism, the use of fire, and the development of advanced tools. But it's 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 language, a large brain, the capacity to create and utilize sophisticated tools, and a cultural diversity.
Evolution occurs when genetic changes allow members of a population to better adapt to their surroundings. This adaptation is triggered by natural selection, a process whereby certain traits are more desirable than others. The more adapted are more likely to pass on their genes to the next generation. This is how all species evolve, and the basis for the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species which share a common ancestor tend to develop similar traits over time. This is because the characteristics make it easier for them to survive and reproduce in their environment.
Every organism has an molecule called DNA that holds the information needed to control their growth. The structure of DNA is composed of base pairs which are 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. Variations in a population can be caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils of the first human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. Despite some differences, these fossils all support the notion that modern humans first appeared in Africa. The fossil evidence and genetic evidence suggest that early humans moved out of Africa into Asia and then Europe.