The Berkeley Evolution Site
The Berkeley site contains resources that can help students and teachers to understand and teach about evolution. The materials are organized into a variety of learning paths like "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains how creatures who are better equipped to adapt biologically to a changing environment survive over time and those that do not disappear. This process of biological 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." Scientifically it refers to a process of change in the characteristics of organisms (or species) over time. This change is based in biological terms on natural selection and drift.
Evolution is a key principle in modern biology. It is a concept that has been tested and verified by thousands of scientific tests. In contrast to other theories in science such as the Copernican theory or the germ theory of disease, the evolution theory does not address questions of religious belief or God's existence.
Early evolutionists, including Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical characteristics were predetermined to change, in a step-like manner, over time. They called this the "Ladder of Nature" or scala naturae. 에볼루션카지노사이트 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 the same ancestry, which can be traced through fossils and other evidence. 에볼루션바카라 is the modern view of evolution, which is supported by numerous lines of scientific research that include molecular genetics.
While scientists don't know exactly how organisms evolved, they are confident that the evolution of life on earth is a result of natural selection and genetic drift. Individuals with advantageous traits are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. In time, this results in gradual changes in the gene pool, which eventually result in new species and forms.
Some scientists also use the term evolution to describe large-scale evolutionary changes, such as the formation of a new species from an ancestral species. Other scientists, such as population geneticists, define it more broadly by referring to a net variation in the frequency of alleles over generations. Both definitions are valid and palatable, but some scientists argue that allele-frequency definitions do not include important aspects of evolutionary process.
Origins of Life
The emergence of life is a crucial stage in evolution. This occurs when living systems begin to develop at the micro level - within individual cells, for example.
The origin of life is an important topic in a variety of disciplines that include biology and chemical. The nature of life is an area of great interest in science because it challenges 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 matter was known as "spontaneous generation" or "spontaneous evolutionary". This was a popular belief before Louis Pasteur's tests showed that the creation of living organisms was not possible through an organic process.
Many scientists still think it is possible to move from living to nonliving substances. The conditions required to make life are not easy to replicate in a laboratory. Researchers who are interested in the evolution and origins of life are also keen to know the physical properties of the early Earth as well as other planets.
Additionally, the evolution of life depends on the sequence of extremely complex chemical reactions that can't be predicted from the fundamental physical laws alone. These include the reading and replication of complex molecules, such as DNA or RNA, to produce proteins that perform a specific function. These chemical reactions are often compared to the chicken-and-egg dilemma of how life came into existence: The emergence of DNA/RNA and protein-based cell machinery is essential to the birth of life, but without the emergence of life, the chemical reaction that is the basis for it does not appear to work.
Abiogenesis research requires collaboration between researchers from different fields. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
Today, the word evolution is used to describe the general changes in genetic traits 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 from natural selection.
This is a method that increases the frequency of genes which confer a survival advantage over others and causes gradual changes in the appearance of a group. These evolutionary changes are triggered by mutations, reshuffling genes during sexual reproduction and the flow of genes.
While reshuffling and mutation of genes happen in all living organisms, the process by which beneficial mutations become more common is referred to as natural selection. This is because, as we've mentioned earlier those who have the advantageous trait are likely to have a higher reproduction rate than those who do not have it. Over the course of many generations, this difference in the numbers of offspring born can result in gradual changes in the average number of advantageous characteristics in a particular population.
A good example of this is the growth of beak size on various species of finches on the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new environment. These changes in shape and form could aid in the creation of new organisms.
The majority of changes are caused by a single mutation, although sometimes multiple occur simultaneously. Most of these changes may be harmful or neutral, but a small number can have a beneficial impact on survival and reproduce, increasing their frequency as time passes. Natural selection is a process that can produce the accumulating change over time that leads to a new species.
Many people confuse evolution with the idea of soft inheritance which is the notion that traits inherited from parents can be changed through conscious choice or abuse. This is a misunderstanding of the biological processes that lead up to the process of evolution. It is more accurate to say that evolution is a two-step, separate process, which involves the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates - a group of mammals that also includes chimpanzees and gorillas and bonobos. Our predecessors walked on two legs, as demonstrated by the first fossils. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In actual fact our closest relatives are the chimpanzees belonging to the Pan genus. This includes pygmy and bonobos. The last common ancestor of humans and chimpanzees was 8 to 6 million years old.
In the course of time, humans have developed a number of traits, including bipedalism as well as the use of fire. They also invented advanced tools. However, it is only in the last 100,000 years or so that most of the essential traits that distinguish us from other species have developed. These include a big brain that is sophisticated human ability to construct and use tools, and the diversity of our culture.
The process of evolution occurs when genetic changes enable members of an organization to better adapt to their environment. Natural selection is the process that drives this adaptation. Certain characteristics are more desirable than others. The more adapted are more likely to pass their genes on to the next generation. This is how all species evolve and the basis of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species which have an ancestor in common will tend to develop similar characteristics in the course of time. It is because these traits help them to live and reproduce in their environment.
Every living thing has a DNA molecule that contains the information needed to control their growth. The structure of DNA is composed of base pairs which are arranged in a spiral, around phosphate and sugar molecules. The sequence of bases found in each strand determines the phenotype - the characteristic appearance and behavior of an individual. The variations in a population are caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the earliest human species Homo erectus, as well as Homo neanderthalensis have been discovered in Africa, Asia and Europe. Despite some differences, these fossils all support the hypothesis that modern humans first came into existence in Africa. Genetic and fossil evidence also suggest that early humans came out of Africa into Asia and then Europe.