The Berkeley Evolution Site
Teachers and students who visit the Berkeley site will find a wealth of resources to aid in understanding and teaching evolution. The materials are organized in different learning paths like "What does T. rex look like?"
Charles Darwin's theory of natural selection explains that over time, animals that are better able to adapt biologically to changing environments thrive, and those that are not extinct. This process of biological evolution is the basis of science.
What is Evolution?
The term "evolution" could be used to refer to a variety of nonscientific meanings. For instance, it can mean "progress" and "descent with modifications." It is an academic term that is used to describe the process of changing characteristics in a species or species. This change is based in biological terms on natural drift and selection.
Evolution is a key principle in the field of biology today. It is a theory that has been proven by thousands of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, evolution does not address issues of religion or God's existence.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve in a stepped-like manner 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.
Darwin presented his theory of evolution in his book On the Origin of Species published in the early 1800s. It states that all species of organisms have a common ancestry which can be traced by fossils and other evidence. This is the current view on evolution, and is supported in many scientific fields that include molecular biology.
Scientists do not know how organisms evolved but they are sure that natural selection and genetic drift are the reason for the evolution of life. People with desirable traits are more likely than others to live and reproduce. These individuals then pass their genes on to the next generation. As time passes the gene pool slowly changes and evolves into new species.
Some scientists employ the term evolution in reference to large-scale changes, such the evolution of an animal from an ancestral one. Some scientists, like population geneticists, define evolution in a broader sense by referring to the net change in the frequency of alleles across generations. Both definitions are acceptable and precise, although some scientists argue that the definition of allele frequency is lacking important features of the evolutionary process.
Origins of Life
The most important step in evolution is the emergence of life. This happens when living systems begin to evolve at the micro level - within individual cells, for example.
The origins of life are an important topic in a variety of fields that include biology and the field of chemistry. The question of how living organisms began is of particular importance in science due to it being an enormous challenge to the theory of evolution. It is sometimes referred to as "the mystery" of life or "abiogenesis."
The notion that life could emerge from non-living objects was referred to as "spontaneous generation" or "spontaneous evolutionary". It was a popular belief prior to Louis Pasteur's tests showed that the creation of living organisms was not achievable through a natural process.
Many scientists believe that it is possible to transition from nonliving materials to living. The conditions necessary to create life are difficult to replicate in a laboratory. This is why researchers investigating the origins of life are also keen to understand the physical properties of the early Earth and other planets.
The life-cycle of a living organism is also dependent on a series of complex chemical reactions that are not predicted by basic physical laws. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that carry out a function, and the replication of these intricate molecules to create new DNA or sequences of RNA. 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 to begin the process of becoming a living organism. Although without life, the chemistry required to enable it appears to be working.
Research in the field of abiogenesis requires cooperation among scientists from various fields. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
The term "evolution" is typically used to describe the accumulated changes in the genetic characteristics of a population over time. These changes could result from adaptation to environmental pressures, as described in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
This process increases the number of genes that offer an advantage for survival in a species, resulting in an overall change in the appearance of an entire group. The specific mechanisms behind these changes in evolutionary process include mutation, reshuffling of genes during sexual reproduction, as well as gene flow between populations.
Natural selection is the process that makes beneficial mutations more frequent. All organisms undergo mutations and reshuffles of their genes. As mentioned above, those who have the advantageous trait have a higher reproduction rate than those who don't. This variation in the number of offspring that are produced over a number of generations could result in a gradual change in the average number of beneficial characteristics in a group.
This can be seen in the evolution of various beak shapes for finches from the Galapagos Islands. They have developed these beaks so they can get food more easily in their new habitat. These changes in the form and shape of organisms can also aid in the creation of new species.
The majority of changes are caused by one mutation, but sometimes several occur at the same time. Most of these changes are neutral or even harmful to the organism, however a small portion of them could have a positive impact on the survival of the organism and its reproduction, thereby increasing their frequency in the population over time. Natural selection is a process that could result in the accumulation of change over time that eventually leads to a new species.
Some people confuse the notion of evolution with the idea that traits inherited can be changed through conscious choice, or through use and abuse, which is called soft inheritance. This is a misinterpretation of the biological processes that lead to the process of evolution. It is more accurate to say that the process of evolution is a two-step, separate process, that is influenced by the forces of natural selection as well as mutation.
Origins of Humans
Humans of today (Homo Sapiens) evolved from primates, which is a group of mammal species which includes chimpanzees and gorillas. The earliest human fossils indicate that our ancestors were bipeds - walkers with two legs. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In actual fact we are the most closely with chimpanzees in the Pan genus that includes pygmy and pygmy chimpanzees and bonobos. The last common human ancestor and chimpanzees lived between 8 and 6 million years ago.
Humans have evolved a variety of traits over time including bipedalism, the use of fire and advanced tools. It's only in the last 100,000 years that we've developed the majority of our essential traits. These include a large brain that is complex, the ability of humans to create and use tools, as well as the diversity of our culture.
Evolution happens when genetic changes allow individuals of a population to better adapt to their surroundings. Natural selection is the process that drives this adaptation. Certain traits are preferred over others. People with better adaptations are more likely to pass on their genes to the next generation. This is how all species evolve and is the foundation of the theory of evolution.
에볼루션바카라사이트 refer to it as the "law of natural selection." The law states that species which have an ancestor in common will tend to develop similar traits as time passes. This is because these characteristics make it easier for them to survive and reproduce in their environments.
Every organism has a DNA molecule that contains the information needed to control their growth. The DNA molecule is made up of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases within each strand determines phenotype which is the person's distinctive appearance and behavior. The 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 found in Africa, Asia and Europe. Although there are some differences they all support the idea that modern humans first came into existence in Africa. The fossil evidence and genetic evidence suggest that early humans migrated out of Africa into Asia and then Europe.