The Berkeley Evolution Site
The Berkeley site has resources that can help students and teachers understand and teach evolution. The resources are arranged into different learning paths like "What did T. rex taste like?"
Charles Darwin's theory on natural selection describes how species that are better equipped to adapt to changes in their environments over time, and those that don't become extinct. This process of evolution is the main focus of science.
What is Evolution?
The term "evolution" can have many nonscientific meanings. For example it could mean "progress" and "descent with modifications." It is scientifically based and is used to describe the process of change of traits over time in organisms or species. This change is based in biological terms on natural selection and drift.
Evolution is one of the fundamental tenets of modern biology. It is an established theory that has stood the test of time and a multitude of scientific tests. Evolution doesn't deal with God's presence or spiritual beliefs in the same way as other scientific theories such as the Copernican or germ theory of diseases.
Early evolutionists like 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. This was known as 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.
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 common ancestors that can be traced through fossils and other evidence. This is the current perspective of evolution, which is supported in a wide range of areas of science which include molecular biology.
Although scientists aren't able to determine exactly how organisms developed, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. People with desirable traits are more likely to live and reproduce, and they pass their genes on to the next generation. As time passes the gene pool gradually changes and evolves into new species.
Some scientists employ the term"evolution" to refer to large-scale changes, such the development of an animal from an ancestral one. Others, like population geneticists, define it more broadly by referring to the net variation in the frequency of alleles over 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 appearance of life. This occurs when living systems begin to develop at the micro level, within cells, for instance.
The origin of life is an important subject in a variety of areas, including biology and the field of chemistry. The question of how living organisms began is a major topic in science due to it being an enormous challenge to the theory of evolution. It is often referred to "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 emergence of living organisms was not possible through the natural process.
Many scientists still believe that it is possible to transition from nonliving materials to living. The conditions needed for the creation of life are difficult to replicate in a laboratory. Researchers interested in the evolution and origins of life are also eager to know the physical properties of the early Earth as well as other planets.
Furthermore, the growth of life depends on a sequence of very complex chemical reactions that can't be predicted based on basic physical laws alone. These include the reading and replication of complex molecules, like DNA or RNA, in order to make proteins that perform a specific function. 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 required to begin the process of becoming a living organism. Although, without life, the chemistry needed to enable it is working.
Research in the field of abiogenesis requires cooperation among scientists from a variety of disciplines. This includes prebiotic chemists, astrobiologists, planetary scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The word evolution is usually used to describe the accumulated changes in the genetic characteristics of an entire 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 natural selection.
This is a method that increases the frequency of those genes that offer an advantage in survival over others which results in a gradual change in the appearance of a group. The specific mechanisms responsible for these evolutionary changes are mutation or reshuffling genes during sexual reproduction, as well as gene flow between populations.
While reshuffling and mutations of genes occur in all living things and the process by which beneficial mutations become more common is known as natural selection. This happens because, as we've mentioned earlier those with the advantageous trait are likely to have a higher reproduction rate than those without it. Over the course of many generations, this differential in the numbers of offspring produced can result in an inclination towards a shift in the amount of desirable traits within a group of.
One good example is the growth of the size of the beaks on different species of finches on the Galapagos Islands, which have evolved different shaped beaks that allow them to easily access food in their new environment. These changes in the shape and appearance of organisms can also be a catalyst for the creation of new species.
The majority of the changes that take place are the result of one mutation, however occasionally, multiple mutations occur at once. The majority of these changes are not harmful or even harmful to the organism, but a small percentage can have a positive impact on the survival of the organism and its reproduction, thereby increasing the frequency of these changes in the population over time. Natural selection is a mechanism that could result in the accumulation of change over time that eventually leads to the creation of a new species.
Some people mistakenly associate evolution with the concept of soft inheritance that is the belief that traits inherited from parents can be changed through conscious choice or by abuse. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that cause it. It is more accurate to say that evolution is a two-step, independent process that 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 includes gorillas, chimpanzees, and bonobos. The earliest human fossils prove that our ancestors were bipeds, walking on two legs. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In fact we are the closest related to the chimpanzees within the Pan genus that includes pygmy and bonobos and pygmy-chimpanzees. The last common ancestor between humans and chimpanzees was 8 to 6 million years old.
Over time humans have developed a number of characteristics, including bipedalism and the use fire. They also created advanced tools. It's only within the last 100,000 years that we've developed the majority of our key traits. These include a big brain that is sophisticated, the ability of humans to construct and use tools, as well as cultural variety.
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. Those with the better adaptations are more likely to pass on their genes to the next generation. This is how all species evolve and the basis for the theory of evolution.
Scientists call this the "law of natural selection." The law states that species that share an ancestor will tend to acquire similar traits in the course of time. This is because these traits allow them to live and reproduce in their natural environment.
에볼루션카지노 possess an molecule called DNA that holds the information needed to control their growth. The DNA structure is made of base pairs arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each string determines the phenotype or the 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 early human species Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. Although there are some differences they all support the idea that modern humans first appeared in Africa. Genetic and fossil evidence also suggest that early humans moved out of Africa into Asia and then Europe.