The Berkeley Evolution Site
The Berkeley site offers resources that can help students and teachers to understand and teach about evolution. The resources are organized into optional learning paths, such as "What does T. rex look like?"
Charles Darwin's theory of natural selection explains that over time creatures that are more adaptable to changing environments thrive, and those that do not become extinct. Science is concerned with this process of evolutionary change.
What is Evolution?
The term "evolution" can have many nonscientific meanings, including "progress" or "descent with modification." 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 the central tenet of modern biology. It is a concept that has been verified by thousands of scientific tests. 에볼루션 무료 바카라 does not deal with spiritual beliefs or God's presence, unlike many other theories in science, like the Copernican or germ theory of diseases.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to change in a stepped-like 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.
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 an ancestry that can be determined through fossils and other evidence. This is the current perspective on evolution, and is supported in a wide range of scientific fields, including molecular biology.
Scientists aren't sure how organisms evolved but they are sure that natural selection and genetic drift is responsible for the evolution of life. People with desirable 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 evolves into new species.
Some scientists use the term evolution in reference to large-scale changes, such the evolution of a species from an ancestral one. Certain scientists, including population geneticists, define the term "evolution" in a more broad sense by referring to the net change in allele frequency over generations. Both definitions are valid and acceptable, but some scientists argue that allele-frequency definitions omit important features of evolution.
Origins of Life
The development of life is an essential step in the process of evolution. This happens when living systems begin to develop at a micro-level - within cells, for example.
The origins of life are a topic in many disciplines such as biology, chemistry, and geology. The nature of life is an area of great interest in science, as it is a 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 matter was known as "spontaneous generation" or "spontaneous evolutionary". This was a popular belief prior to Louis Pasteur's experiments proved that the emergence of living organisms was not achievable through an organic process.
Many scientists believe it is possible to move from nonliving to living substances. However, the conditions that are required are extremely difficult to reproduce in labs. Researchers interested in the origins and evolution of life are also keen to learn about the physical characteristics of the early Earth as well as other planets.
Additionally, the evolution of life is dependent on the sequence of extremely complex chemical reactions that can't be predicted from basic physical laws alone. These include the reading of long information-rich molecules (DNA or RNA) into proteins that perform functions, and the replication of these complex molecules to create new DNA or RNA sequences. These chemical reactions are comparable to the chicken-and-egg problem that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is necessary for the onset life. However, without life, the chemistry required to enable it appears to be working.
Research in the field of abiogenesis requires collaboration among scientists from many different fields. This includes prebiotic chemists the astrobiologists, the planet scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used to describe the accumulated changes in genetic characteristics of an entire population over time. These changes can result from adaptation to environmental pressures, as explained in the article on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This is a process that increases the frequency of genes in a species that confer a survival advantage over others which results in an ongoing change in the overall appearance of a particular population. These evolutionary changes are triggered by mutations, reshuffling of genes during sexual reproduction and gene flow.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo changes and reshuffles of their genes. This happens because, as we've mentioned earlier, those individuals with the beneficial trait tend to have a higher reproductive rate than those with it. This variation in the number of offspring produced over a long period of time can result in a gradual change in the number of advantageous traits in the group.
One good example is the increase in the size of the beaks on different species of finches on the Galapagos Islands, which have evolved different shaped beaks that allow them to easily access food in their new habitat. These changes in shape and form could also aid in the creation of new species.
The majority of changes are caused by a single mutation, however sometimes multiple occur at once. The majority of these changes could be neutral or even harmful however, a few can have a beneficial impact on the survival of the species and reproduce and increase their frequency as time passes. This is the mechanism of natural selection and it could eventually result in the gradual changes that eventually result in an entirely new species.
Many people mistakenly associate evolution with the concept of soft inheritance, which is the idea that inherited traits can be changed through deliberate choice or misuse. 에볼루션사이트 is a misunderstanding of the biological processes that lead up to evolution. A more accurate description of evolution is that it involves a two-step process, involving the independent and often conflicting forces of mutation and natural selection.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates - a species of mammals that includes gorillas, chimpanzees, and bonobos. The earliest human fossils show that our ancestors were bipeds - walkers on two legs. Genetic and biological similarities show that we have the same ancestry with the chimpanzees. In reality our closest relatives are chimpanzees from 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 traits throughout time such as bipedalism, use of fire, and the development of advanced tools. It is only within the last 100,000 years that we have developed the majority of our important traits. These include language, a large brain, the capacity to build and use complex tools, and the ability to adapt to cultural differences.
Evolution occurs when genetic changes enable members of the group to better adapt to their environment. Natural selection is the process that triggers this adaptation. Certain characteristics are more desirable than others. The better adapted 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 this as the "law of natural selection." The law states that species that have a common ancestor are likely to acquire similar traits in the course of time. This is because those characteristics make it easier for them to live and reproduce in their environment.
All organisms possess a DNA molecule that contains the information necessary to direct their growth. The DNA molecule consists of base pairs that are arranged in a spiral around sugar molecules and phosphate molecules. The sequence of bases in each strand determines the phenotype - the characteristic appearance and behavior of a person. 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. Although there are some differences the fossils all support the notion that modern humans first appeared in Africa. The evidence from fossils and genetics suggests that early humans left Africa and migrated to Asia and Europe.