The Berkeley Evolution Site
The Berkeley site contains resources that can help students and teachers learn about and teach evolution. The resources are organized into optional learning paths for example "What does T. rex look like?"
Charles Darwin's theory on natural selection explains how animals who are better equipped to adapt biologically to changing environments over time, and those that do not disappear. This process of biological evolution is what science is all about.
What is Evolution?
The term "evolution" could have a variety of meanings that are not scientific. For instance, it can mean "progress" and "descent with modifications." It is a scientific term that is used to describe the process of change of characteristics over time in organisms or species. This change is based in biological terms on natural drift and selection.
Evolution is one of the fundamental tenets of modern biology. It is a concept that has been tested and confirmed by a myriad of scientific tests. In contrast to other theories in science like the Copernican theory or the germ theory of disease, evolution does not address issues of religious belief or the existence of God.
Early evolutionists, including Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change, in a step-wise way, over time. This was known as 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 share an ancestry that can be traced using fossils and other evidence. This is the current understanding of evolution, which is supported by numerous lines of scientific research, including molecular genetics.
Although scientists aren't able to determine exactly how organisms developed but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. 에볼루션사이트 with traits that are advantageous are more likely to live and reproduce, and they pass their genes on to the next generation. As time passes this leads to an accumulation of changes to the gene pool that gradually create new species and types.
Some scientists employ the term"evolution" in reference to large-scale change, such as the evolution of one species from an ancestral one. Other scientists, such as population geneticists, define evolution more broadly, referring to a net variation in the frequency of alleles over generations. Both definitions are valid and reliable however, some scientists claim that the allele-frequency definition is missing essential aspects of the evolution process.
Origins of Life
One of the most crucial steps in evolution is the emergence of life. This occurs when living systems begin to evolve at the micro level, within individual cells, for example.
The origins of life are a topic in many disciplines, including biology, chemistry and geology. The question of how living things got their start has a special place in science because it is a major challenge to the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis."
The idea 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 experiments proved that the emergence of living organisms was not possible through a natural process.
Many scientists still believe it is possible to transition from nonliving substances to living. The conditions required for the creation of life are difficult to replicate in a laboratory. Researchers investigating the origins of life are also interested in understanding the physical properties of early Earth and other planets.
In addition, the development of life depends on an intricate sequence of chemical reactions that cannot be predicted based on basic physical laws alone. These include the reading and replication of complex molecules, like DNA or RNA, to create proteins that perform a specific function. These chemical reactions are often compared to the chicken-and-egg dilemma of how life came into existence in the first place. The development of DNA/RNA as well as protein-based cell machinery is essential for the beginning of life, however, without the appearance of life the chemical reaction that is the basis for it does not appear to work.
Research in the field of abiogenesis requires cooperation among scientists from a variety of disciplines. This includes prebiotic scientists, astrobiologists, and planet scientists.
Evolutionary Changes
The word evolution is usually used to refer to the accumulated changes in genetic characteristics of an entire population over time. These changes may be the result of the adaptation to environmental pressures as explained in Darwinism.
The latter is a mechanism that increases the frequency of those genes in a species that offer an advantage in survival over other species, resulting in a gradual change in the overall appearance of a population. These evolutionary changes are triggered by mutations, reshuffling of genes during sexual reproduction and the flow of genes.
While reshuffling and mutation of genes occur in all living organisms The process through which beneficial mutations are more frequent is referred to as natural selection. As mentioned above, those with the beneficial characteristic have a higher reproduction rate than those that do not. This difference in the number of offspring that are produced over a long period of time can result in a gradual change in the number of advantageous traits within the group.
An excellent 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 habitat. These changes in the shape and appearance of living organisms may also be a catalyst for the creation of new species.
The majority of the changes that take place are caused by one mutation, however occasionally, multiple mutations occur simultaneously. The majority of these changes could be harmful or neutral however, a few could have a positive impact on the survival of the species and reproduce and increase their frequency over time. This is the mechanism of natural selection, and it can, over time, produce the cumulative changes that eventually lead to an entirely new species.
Some people confuse the notion of evolution with the notion that the traits inherited from parents can be altered by conscious choice, or through use and abuse, which is known as soft inheritance. This is a misunderstanding of the biological processes that lead up to the process of evolution. It is more accurate to say that the process of evolution is a two-step, independent process, that is influenced by the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species that includes chimpanzees and gorillas. The earliest human fossils show that our ancestors were bipeds. They were walking on two legs. Biological and genetic similarities indicate that we have a close relationship with chimpanzees. In reality, our closest relatives are the chimpanzees of the Pan genus. This includes pygmy and bonobos. The last common ancestor of modern humans and chimpanzees lived between 8 and 6 million years ago.
Over time humans have developed a variety of characteristics, including bipedalism and the use fire. They also developed advanced tools. It is only in the past 100,000 years or so that the majority of the important traits that distinguish us from other species have emerged. They include language, a large brain, the ability to build and use complex tools, as well as cultural diversity.
Evolution occurs when genetic changes enable members of the group to better adapt to their environment. Natural selection is the process that drives this adaptation. Certain characteristics are more desirable than others. The better adjusted are more likely to pass on their genes to the next generation. This is how all species evolve, and the foundation for the theory of evolution.
Scientists call this the "law of natural selection." The law states species that have a common ancestor are likely to acquire similar traits in the course of time. This is because these traits allow them to live and reproduce in their environment.
Every living thing has an molecule called DNA that holds the information needed to control their growth. The structure of DNA is composed of base pair arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each strand determines the phenotype - the characteristic appearance and behavior of an individual. Different changes and reshuffling of genetic material (known as alleles) during sexual reproduction can cause variation in a population.
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 hypothesis that modern humans first came into existence in Africa. The fossil and genetic evidence suggests that early humans left Africa and migrated to Asia and Europe.