The Berkeley Evolution Site
The Berkeley site contains resources that can assist students and teachers to understand and teach about evolution. The materials are arranged into different learning paths like "What did T. rex taste like?"
Charles Darwin's theory on natural selection describes how species who are better equipped to adapt biologically to changing environment survive over time and those that don't disappear. This process of biological evolution is the basis of science.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For instance it could refer to "progress" and "descent with modifications." It is scientifically based and is used to describe the process of change of characteristics in a species or species. In terms of biology the change is caused by natural selection and genetic drift.
Evolution is one of the fundamental tenets of modern biology. It is a theory that has been proven by thousands of scientific tests. Evolution does not deal with the existence of God or religious beliefs in the same way as other scientific theories such as the Copernican or germ theory of diseases.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change in a gradual manner, as time passes. This was known as 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 traced through fossils and other evidence. This is the modern view of evolution, and is supported by a variety of lines of research in science which includes molecular genetics.
Scientists aren't sure how organisms evolved but they are sure that natural selection and genetic drift are responsible for the evolution of life. Individuals with advantageous characteristics are more likely to survive and reproduce. These individuals transmit their genes to the next generation. As time passes this leads to an accumulation of changes in the gene pool which gradually create new species and types.
Some scientists use the term evolution in reference to large-scale changes, like the development of an animal from an ancestral one. Other scientists, like population geneticists, define evolution more broadly, referring to an overall variation in the frequency of alleles over generations. Both definitions are accurate and acceptable, but some scientists argue that allele-frequency definitions miss important aspects of the evolutionary process.
Origins of Life
A key step in evolution is the emergence of life. The emergence of life occurs when living systems begin to develop at a microscopic level, such as within cells.
The origins of life are an important subject in a variety of areas that include biology and chemistry. The nature of life is a subject that is of immense interest to scientists, as it is a challenge to the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
Traditionally, the notion that life could emerge from nonliving things is called spontaneous generation or "spontaneous evolution." This was a popular view before Louis Pasteur's experiments proved that it was impossible for the emergence of life to happen through the natural process.
Many scientists believe that it is possible to make the transition from nonliving materials to living. However, the conditions required are extremely difficult to replicate in a laboratory. 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.
The growth of life is dependent on a number of complex chemical reactions, which are not predicted by the basic physical laws. These include the reading and re-reading of complex molecules, such as DNA or RNA, in order to make proteins that perform a specific function. These chemical reactions are often compared with the chicken-and-egg problem of how life began with the development of DNA/RNA as well as protein-based cell machinery is essential for the onset of life, however, without the development of life, the chemical reaction that is the basis for it is not working.
Research in the field of abiogenesis requires collaboration among scientists from various disciplines. 에볼루션 바카라 무료체험 includes prebiotic chemists, the astrobiologists, the planet scientists geophysicists and geologists.
Evolutionary Changes
The term "evolution" is commonly used to describe the cumulative changes in the genetic traits of a population over time. These changes can result from adaptation to environmental pressures as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or natural selection.
This is a process that increases the frequency of those genes which confer an advantage in survival over other species which results in an ongoing change in the appearance of a group. The specific mechanisms behind these evolutionary changes include mutation and reshuffling of genes in sexual reproduction, and gene flow between populations.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo mutations and reshuffles in their genes. This happens because, as mentioned above, those individuals with the beneficial trait tend to have a higher reproductive rate than those with it. This difference in the number of offspring produced over a long period of time can cause a gradual change in the average number of beneficial characteristics in the group.
This is evident in the evolution of different beak designs on finches that are found in the Galapagos Islands. They have created these beaks to ensure that they can access food more easily in their new environment. 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 at once. Most of these changes can be negative or even harmful, but a small number can have a beneficial impact on survival and reproduce, increasing their frequency over time. Natural selection is a process that could result in the accumulation of changes over time that lead to the creation of a new species.
Many people confuse the concept of evolution with the notion that the traits inherited from parents can be altered through conscious choice or by use and abuse, a notion called soft inheritance. This is a misinterpretation of the biological processes that lead up to evolution. It is more accurate to say that evolution is a two-step, separate process, that is influenced by the forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates, a group of mammals that includes chimpanzees, gorillas, and bonobos. The earliest human fossils indicate that our ancestors were bipeds - walkers with two legs. Biological and genetic similarities indicate that we share the same ancestry with Chimpanzees. In reality, we are most closely related to the chimpanzees within the Pan Genus, which includes bonobos and pygmy chimpanzees. The last common human ancestor and chimpanzees was born between 8 and 6 million years ago.
As time has passed humans have developed a variety of traits, including bipedalism as well as the use of fire. They also developed advanced tools. It is only in the past 100,000 years or so that most of the important characteristics that differentiate us from other species have developed. They include language, a large brain, the capacity to build and use sophisticated tools, and a the ability to adapt to cultural differences.
Evolution happens when genetic changes allow members of a population to better adapt to their surroundings. This adaptation is triggered by natural selection, a process that determines certain traits are preferred over others. The ones with the best adaptations are more likely to pass on their genes to the next generation. This is the way all species evolve and the basis for the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states species that have a common ancestor are likely to develop similar characteristics as time passes. This is because these traits allow them to reproduce and survive within their environment.
Every living thing has DNA molecules, which provides the information necessary to direct their growth and development. The DNA structure is composed of base pairs arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. Different mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction can cause variations in a population.
Fossils from the early human species Homo erectus, as well as Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite a few variations in their appearance, all support the hypothesis of the origins of modern humans in Africa. The evidence from fossils and genetics suggests that early humans left Africa and migrated to Asia and Europe.