The Berkeley Evolution Site
The Berkeley site offers resources that can help students and educators learn about and teach evolution. The materials are organized in optional learning paths, such as "What does T. rex look like?"
Charles Darwin's theory of natural selection explains that in time, creatures more able to adapt to changing environments thrive, and those that don't become extinct. Science is all about this process of biological evolution.
What is Evolution?
The word evolution can have a variety of meanings that are not scientific. For example it could mean "progress" and "descent with modifications." Scientifically, it refers to a process of change in the characteristics of living things (or species) over time. In biological terms this change is caused by natural selection and genetic drift.
Evolution is a key tenet in modern biology. It is a concept that has been tested and confirmed through thousands of scientific tests. Evolution does not deal with God's presence or spiritual beliefs, unlike many other scientific theories such as the Copernican or germ theory of disease.
Early evolutionists, such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to evolve in a step-like fashion 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 have common ancestors that can be traced by fossils and other evidence. This is the current understanding of evolution, and is supported by a variety of lines of research in science that include molecular genetics.
simply click for source don't know how organisms evolved however they are certain that natural selection and genetic drift is responsible for the development of life. Individuals with advantageous characteristics are more likely than others to survive and reproduce. These individuals then pass their genes to the next generation. As time passes the gene pool gradually 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 formation of the new species from an ancestral species. Some scientists, like population geneticists, define the term "evolution" in a broad sense, using the term "net change" to refer to the change in allele frequency over generations. Both definitions are acceptable and precise however some scientists believe that the allele-frequency definition omits important features of the evolutionary process.
Origins of Life
The most important step in evolution is the appearance of life. This occurs when living systems begin to evolve at a micro-level - within individual cells, for example.
The origin of life is a topic in many disciplines such as biology, chemistry, and geology. The origin of life is a subject that is of immense interest to scientists, as it is a challenge to the theory of evolution. 에볼루션카지노사이트 is often described as "the mystery of life," or "abiogenesis."
Traditionally, the idea that life can arise from nonliving things is called spontaneous generation or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments showed that it was impossible for the emergence of life to be a result of a purely natural process.
Many scientists still believe it is possible to make the transition from nonliving materials to living. However, the conditions that are required are extremely difficult to replicate in the laboratory. Researchers studying the origins of life are also interested in understanding the physical properties of early Earth and other planets.
In addition, the development of life is an intricate sequence of chemical reactions that cannot be predicted from basic physical laws on their own. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that perform some function and the replication of these intricate molecules to create new DNA or sequences of RNA. These chemical reactions are often compared with the chicken-and-egg problem of how life first appeared: The appearance of DNA/RNA and protein-based cell machinery is crucial for the beginning of life, however, without the appearance of life the chemical process that allows it isn't working.
Abiogenesis research requires collaboration among researchers from different fields. This includes prebiotic chemists, astrobiologists, planetary scientists geophysicists and geologists.
Evolutionary Changes
Today, the word evolution is used to describe the general changes in genetic traits over time. These changes can result from the response to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
This is a process that increases the frequency of those genes that offer an advantage in survival over others, resulting in a gradual change in the overall appearance of a group. The specific mechanisms that cause these evolutionary changes include mutation and reshuffling of genes in sexual reproduction, and also gene flow between populations.
While reshuffling and mutations of genes happen in all living organisms The process through which beneficial mutations are more prevalent is referred to as natural selection. As noted above, individuals who have the advantageous trait have a higher reproduction rate than those who do not. Over many generations, this difference in the number of offspring produced can result in an inclination towards a shift in the number of beneficial traits in a population.
This can be seen in the evolution of different beak designs on finches that are found in the Galapagos Islands. They have created these beaks to ensure they can get food more easily in their new environment. These changes in the shape and form of organisms could also be a catalyst for the creation of new species.
Most of the changes that take place are the result of one mutation, however sometimes, several changes occur at the same time. Most of these changes may be negative or even harmful, but a small number can have a beneficial impact on survival and reproduce with increasing frequency as time passes. Natural selection is a process that causes the accumulating changes over time that lead to the creation of a new species.
Some people confuse the notion of evolution with the idea that inherited characteristics can be changed through conscious choice or use and abuse, a concept called soft inheritance. This is a misunderstood understanding 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 that involves the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a species of mammal species that includes chimpanzees and gorillas. Our predecessors walked on two legs, as evidenced by the first fossils. Genetic and biological similarities suggest that we are closely related to chimpanzees. In actual fact, we are most closely connected to chimpanzees belonging to the Pan genus that includes pygmy and bonobos and pygmy chimpanzees. The last common human ancestor as well as chimpanzees was born between 8 and 6 million years ago.
Humans have evolved a variety of traits throughout time such as bipedalism, use of fire, and the development of advanced tools. It is only in the past 100,000 years or so that the majority of the important characteristics that differentiate us from other species have been developed. They include a huge brain that is sophisticated and the capacity of humans to construct and use tools, and the diversity of our culture.
Evolution occurs when genetic changes allow individuals in a group to better adapt to their surroundings. This adaptation is driven by natural selection, which is a process by which certain traits are favored over other traits. 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 is the basis for the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species which 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.
All organisms possess a DNA molecule that contains the information needed to guide their growth. The DNA structure is made of base pairs which are arranged in a spiral, around sugar and phosphate molecules. The sequence of bases within each strand determines the phenotype - the distinctive appearance and behavior of a person. The variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the earliest human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. These fossils, despite differences in their appearance all support the theory of the origins of modern humans in Africa. Evidence from fossils and genetics suggest that early humans moved out of Africa into Asia and then Europe.