The Berkeley Evolution Site
The Berkeley site contains resources that can help students and educators to understand and teach about evolution. The materials are arranged in different learning paths for example "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how creatures that are better equipped to adapt biologically to changing environments over time, and those who do not disappear. This process of evolution in biology is the basis of science.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For example it could refer to "progress" and "descent with modifications." It is scientifically based and refers to the process of changing characteristics in a species or species. In biological terms this change is caused by natural selection and genetic drift.
Evolution is a fundamental concept in modern biology. It is a well-supported theory that has stood up to the test of time and a multitude of scientific studies. In contrast to other theories in science, such as the Copernican theory or the germ theory of disease, evolution is not a discussion of religious belief or the existence of God.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical characteristics were predetermined to change in a step-like way, over time. They called this the "Ladder of Nature" or scala naturae. Charles Lyell used the term to describe this idea in his Principles of Geology, first published in 1833.
In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It asserts that all species of organisms have common ancestors that can be traced by fossils and other evidence. This is the modern view of evolution, and is supported by a variety of research lines in science which includes molecular genetics.
While scientists do not know exactly how organisms developed however they are sure that the evolution of life on earth is the result of natural selection and genetic drift. Individuals with advantageous traits are more likely to live and reproduce, and these individuals pass their genes on to the next generation. Over time, the gene pool gradually changes and evolves into new species.
Certain scientists also use the term"evolution" to refer to large-scale changes in evolutionary processes like the creation of the new species from an ancestral species. Others, like population geneticists, define it more broadly, referring to the net variation in the frequency of alleles over generations. Both definitions are valid and palatable, but certain scientists argue that allele frequency definitions do not include important aspects of evolution.
Origins of Life
One of the most crucial steps in evolution is the emergence of life. This happens when living systems begin to develop at the micro level, within individual cells, for example.
The origins of life is one of the major topics in various disciplines, including 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 described as "the mystery of life," or "abiogenesis."
The idea that life could arise from non-living things was called "spontaneous generation" or "spontaneous evolutionary". This was a popular belief prior to Louis Pasteur's tests proved that the development of living organisms was not possible by an organic process.
Many scientists still think it is possible to go from living to nonliving substances. However, the conditions required are extremely difficult to reproduce in a laboratory. This is why scientists studying the nature of life are also interested in determining the physical properties of 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 simple physical laws. These include the reading of long information-rich molecules (DNA or RNA) into proteins that carry out some function as well as the replication of these intricate molecules to create new DNA or RNA sequences. These chemical reactions can be compared with the chicken-and-egg issue: the emergence and development of DNA/RNA, a protein-based cell machinery, is essential for the beginning of life. But without life, the chemistry required to enable it does appear to work.
Abiogenesis research requires collaboration with researchers from different disciplines. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
The term "evolution" is typically used today to refer to the accumulated changes in the genetic characteristics of populations over time. These changes can result from adaptation to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This mechanism also increases the frequency of genes that confer a survival advantage in a species, resulting in an overall change in the appearance of a group. 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 genes. This is because, as we've mentioned earlier those who have the beneficial trait tend to have a higher reproduction rate than those without it. This differential in the number of offspring that are produced over a long period of time can cause a gradual change in the average number of beneficial traits within the group.
One good example is the increase in beak size on various species of finches found on the Galapagos Islands, which have evolved different shaped beaks to allow them to more easily access food in their new home. These changes in shape and form could also aid in the creation of new species.
Most of the changes that take place are caused by one mutation, but occasionally several will happen at once. The majority of these changes could be negative or even harmful however, a few could have a positive impact on survival and reproduce, increasing their frequency as time passes. Natural selection is a mechanism that could result in the accumulation of change over time that leads to the creation of a new species.
Many people confuse the concept of evolution with the notion that traits inherited can be altered by conscious choice or by use and abuse, a notion called soft inheritance. This is a misinterpretation of the biological processes that lead up to the process of evolution. A more accurate description of evolution is that it is a two-step procedure that involves the distinct, and often competing, forces of mutation and natural selection.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species that includes gorillas and chimpanzees. The earliest human fossils prove that our ancestors were bipeds. They were walkers on two legs. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In reality we are the closest related to the chimpanzees within the Pan genus that includes pygmy and bonobos and pygmy-chimpanzees. The last common human ancestor as well as chimpanzees was between 8 and 6 million years ago.
Humans have developed a range of characteristics over time, including bipedalism, the use of fire, and the development of advanced tools. It is only in the last 100,000 years or so that most of the traits that distinguish us from other species have developed. They include a huge, complex brain, the ability of humans to build and use tools, as well as cultural diversity.
The process of evolution occurs when genetic changes allow individuals in a group to better adapt to their environment. This adaptation is driven by natural selection, a process that determines certain traits are more desirable than others. 에볼루션 바카라 with the better adaptations are more likely to pass their genes to the next generation. This is the way all species evolve, and the foundation for the theory of evolution.
Scientists call this the "law of natural selection." The law states species that share an ancestor will tend to develop similar characteristics over time. It is because these traits make it easier to survive and reproduce within their environment.
Every living thing has an molecule called DNA that holds the information needed to guide their growth. The DNA molecule consists of base pairs arranged spirally around phosphate molecules and sugar molecules. The sequence of bases within each strand determines phenotype or the individual's unique appearance and behavior. Variations in mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction cause variation in a group.
Fossils of 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 theory of modern humans' origins in Africa. The genetic and fossil evidence suggests that early humans left Africa and migrated to Asia and Europe.