The Berkeley Evolution Site
The Berkeley site contains resources that can assist students and teachers to understand and teach about evolution. The materials are organized into a variety of learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains that over time, animals that are more able to adapt to changing environments thrive, and those that don't become extinct. 에볼루션 게이밍 is all about the process of biological evolution.
What is Evolution?
The term "evolution" could be used to refer to a variety of nonscientific meanings. For example it could refer to "progress" and "descent with modifications." Scientifically, it refers to a process of changes in the traits of organisms (or species) over time. In terms of biology, this change is due to natural selection and genetic drift.
Evolution is a central tenet of modern biology. It is a concept that has been proven by a myriad of scientific tests. Unlike many other scientific theories, such as the Copernican theory or the germ theory of disease, the evolution theory does not address issues of religion or God's existence.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change in a gradual manner, over time. They referred to this as the "Ladder of Nature" or scala naturae. Charles Lyell used the term to describe this concept 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 claims that different species of organisms share an ancestry that can be proven through fossils and other evidence. This is the current understanding of evolution, which is supported by a variety of lines of research in science which includes molecular genetics.
Scientists don't know the evolution of organisms however they are certain that natural selection and genetic drift is responsible for the development of life. Individuals with advantageous traits are more likely to survive and reproduce, and these individuals transmit their genes to the next generation. As time passes the gene pool gradually changes and evolves into new species.
Some scientists also use the term evolution to refer to large-scale evolutionary changes such as the creation of the new species from an ancestral species. Certain scientists, including population geneticists define evolution in a more broad 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 allele-frequency definition omits essential aspects of the evolution process.
Origins of Life
A key step in evolution is the emergence of life. This happens when living systems begin to evolve at the micro level - within individual cells, for instance.
The origins of life are an important issue in many disciplines, including biology and chemistry. The origin of life is a topic that is of immense interest to scientists, as it challenges the theory of evolution. It is often called "the mystery of life," or "abiogenesis."
Traditionally, the idea that life could emerge from nonliving things is called spontaneous generation or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the development of life to be a result of a purely natural process.
Many scientists still believe that it is possible to transition from nonliving substances to living. The conditions necessary to create life are difficult to replicate in a laboratory. This is why researchers investigating the beginnings of life are also interested in understanding the physical properties of early Earth and other planets.
In addition, the development of life is dependent on an intricate sequence of chemical reactions that can't be predicted from the fundamental physical laws alone. These include the reading of long, information-rich molecules (DNA or RNA) into proteins that perform a function, and the replication of these intricate molecules to generate new DNA or RNA sequences. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is necessary for the onset life. But without life, the chemistry needed to create it appears to be working.
Abiogenesis research requires collaboration with scientists from various fields. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
The term "evolution" is commonly used to refer to the accumulated changes in the genetic traits of a population over time. These changes can be the result of adaptation to environmental pressures as described 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 an ongoing change in the appearance of a particular population. The specific mechanisms behind these evolutionary changes are mutation and reshuffling of genes in sexual reproduction, as well as gene flow between populations.
While reshuffling and mutation of genes occur in all organisms and the process by which beneficial mutations are more frequent is known as natural selection. As mentioned above, those who possess the desirable trait have a higher reproductive rate than those who don't. This variation in the number of offspring born over a long period of time can result in a gradual change in the average number advantageous traits in the group.
This can be seen in the evolution of various beak shapes on finches from the Galapagos Islands. They have developed these beaks so that they can access food more quickly in their new home. These changes in the form and shape of organisms could also be a catalyst for the creation of new species.
The majority of changes are caused by a single mutation, however sometimes multiple occur simultaneously. Most of these changes are neutral or even harmful to the organism however, a small proportion of them can have a positive impact on the longevity and reproduction of the species, thus increasing the frequency of these changes in the population over time. This is the mechanism of natural selection and it is able to be a time-consuming process that produces the accumulating changes that eventually lead to an entirely new species.
Some people confuse the notion of evolution with the notion that inherited characteristics can be altered by conscious choice, or through use and abuse, which is known as soft inheritance. This is a misinterpretation of the nature of evolution, and of the actual biological processes that trigger it. A more precise description is that evolution is a two-step process which involves the separate, and often competing, forces of mutation and natural selection.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates, a group of mammals that includes chimpanzees and gorillas and bonobos. The earliest human fossils indicate that our ancestors were bipeds. They were walking on two legs. Biological and genetic similarities indicate that we share the same ancestry with the chimpanzees. In reality, we are most closely related to the chimpanzees within the Pan Genus which includes pygmy chimpanzees and bonobos. The last common ancestor of modern humans and chimpanzees was between 8 and 6 million years ago.
As time has passed, humans have developed a range of characteristics, such as bipedalism as well as the use of fire. They also invented advanced tools. It's only within the last 100,000 years that we have developed the majority of our key traits. They include a huge brain that is sophisticated human ability to create and use tools, as well as the diversity of our culture.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their environment. Natural selection is the mechanism that drives this change. Certain traits are preferred over others. The more adaptable are more likely to pass on their genes to the next generation. This is the way all species evolve and the basis for the theory of evolution.
Scientists call it the "law of natural selection." The law states species that have a common ancestor are likely to develop similar traits over time. This is because these traits allow them to survive and reproduce in their natural environment.
All organisms have a DNA molecule, which is the source of information that helps direct their growth and development. The DNA structure is composed of base pairs arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines phenotype or the individual's unique appearance and behavior. Variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the earliest human species Homo erectus, as well as Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite some differences in their appearance, all support the idea of the origins of modern humans in Africa. The evidence from fossils and genetics suggests that early humans left Africa and moved to Asia and Europe.