The Berkeley Evolution Site
The Berkeley site offers resources that can help students and educators understand and teach evolution. The resources are organized into a variety of learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory on natural selection explains how creatures who are better equipped to adapt biologically to a changing environment survive over time and those that don't disappear. Science is all about the process of biological evolution.
What is Evolution?
The word evolution has many nonscientific meanings. For instance "progress" or "descent with modification." It is scientifically based and refers to the process of change of characteristics in a species or species. In biological terms the change is based on natural selection and genetic drift.
Evolution is a key concept in modern biology. It is a well-supported theory that has withstood the test of time and thousands of scientific experiments. It does not address God's presence or spiritual beliefs, unlike many other theories in science, like the Copernican or germ theory of disease.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve in a step-like fashion over time. This was called 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 asserts that different species of organisms share an ancestry that can be proven through fossils and other evidence. This is the current understanding of evolution, which is supported by a variety of lines of research in science that include molecular genetics.
Although scientists aren't able to determine the exact mechanism by which organisms evolved but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. People with advantages are more likely to survive and reproduce. They then pass their genes on to the next generation. As time passes the gene pool slowly changes and evolves into new species.
Some scientists also use the term evolution to refer to large-scale changes in evolutionary processes such as the creation of an entirely new species from an ancestral species. Other scientists, like population geneticists, define the term "evolution" more broadly, referring to the net variation in the frequency of alleles over generations. Both definitions are acceptable and precise however some scientists believe that the allele-frequency definition is missing crucial aspects of the evolutionary process.
Origins of Life
A key step in evolution is the appearance of life. This occurs when living systems begin to evolve at a micro-level - within individual cells, for instance.
The origin of life is an important issue in many disciplines such as biology and chemical. The question of how living organisms began is a major topic in science since it poses an important challenge to the theory of evolution. It is often called "the mystery of life," or "abiogenesis."
Traditionally, the belief that life can arise from nonliving objects 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 emergence of life to be a result of an entirely natural process.
Many scientists believe that it is possible to make the transition from nonliving substances to life. However, the conditions needed are extremely difficult to replicate in the laboratory. Researchers interested in the evolution and origins of life are also eager to understand the physical properties of the early Earth as well as other planets.
Furthermore, the growth of life is a sequence of very complex chemical reactions that can't be predicted from the fundamental physical laws on their own. These include the reading and replication of complex molecules, such as DNA or RNA, in order to make proteins that serve a specific function. These chemical reactions are often compared to the chicken-and-egg dilemma of how life began with the appearance of DNA/RNA and protein-based cell machinery is crucial for the onset of life, but without the emergence of life, the chemical process that allows it does not appear to work.
Abiogenesis research requires collaboration between researchers from different fields. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
The term "evolution" today is used to describe the cumulative changes in genetic characteristics over time. These changes may 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 offer a survival advantage over others, resulting in an ongoing change in the appearance of a population. The specific mechanisms responsible for these changes in evolutionary process include mutation or reshuffling genes during 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 of genes. As noted above, individuals who have the advantageous characteristic have a higher reproduction rate than those that do not. This difference in the number of offspring that are produced over a number of generations could cause a gradual change in the average number of beneficial characteristics in a group.
An excellent example is the increase in beak size on different species of finches in the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new home. Read Even more in the form and shape of organisms can also be a catalyst for the creation of new species.
The majority of the changes that take place are caused by one mutation, but sometimes, several changes occur simultaneously. Most of these changes are neither harmful nor even detrimental to the organism, however a small portion of them could have an advantageous impact on the longevity and reproduction of the species, thus increasing the frequency of these changes in the population over time. This is the way of natural selection and it could be a time-consuming process that produces the cumulative changes that eventually result in a new species.
Some people confuse the notion of evolution with the notion that the traits inherited from parents can be altered by conscious choice or by use and abuse, which is called soft inheritance. This is a misinterpretation of the nature of evolution and of the actual biological processes that cause 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 as well as mutation.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates, a group of mammals that also includes gorillas, chimpanzees, and bonobos. The earliest human fossils indicate that our ancestors were bipeds, walking on two legs. Genetic and biological similarities suggest that we are closely related to chimpanzees. In reality we are the closest with chimpanzees in the Pan Genus which includes bonobos and pygmy chimpanzees. The last common ancestor of modern humans and chimpanzees was between 8 and 6 million years ago.
In the course of time humans have developed a variety of traits, including bipedalism and the use of fire. They also developed advanced tools. It's only in the last 100,000 years that we've developed the majority of our key characteristics. These include a big, complex brain human ability to create and use tools, and cultural variety.
Evolution happens when genetic changes allow individuals in a group to better adapt to their surroundings. Natural selection is the mechanism that drives this change. Certain traits are preferred over others. The better adaptable are more likely to pass their genes on to the next generation. This is the way all species evolve and is the basis of the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species that have a common ancestor, tend to develop similar characteristics over time. It is because these traits help them to survive and reproduce within their environment.
Every organism has a DNA molecule, which is the source of information that helps control their growth and development. The DNA molecule is composed of base pairs that are spirally arranged around sugar molecules and phosphate molecules. 에볼루션 카지노 사이트 of bases in each strand determines the phenotype, the appearance and behavior of a person. Variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the first human species, Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite variations in their appearance, all support the idea that modern humans' ancestors originated in Africa. The genetic and fossil evidence suggests that early humans left Africa and moved to Asia and Europe.