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 different learning paths for example "What does T. rex look like?"
Charles Darwin's theory on natural selection explains how animals who are better able to adapt to changes in their environment survive over time and those that do not end up becoming extinct. Science is concerned with this process of biological evolutionary change.
What is Evolution?
The word evolution can have many nonscientific meanings. For instance it could mean "progress" and "descent with modifications." It is a scientific term that refers to the process of changing characteristics in a species or species. In terms of biology, this change is based on natural selection and genetic drift.
Evolution is the central tenet of modern biology. It is an accepted theory that has withstood the tests of time and thousands of scientific tests. Unlike many other scientific theories such as the Copernican theory or the germ theory of disease, evolution does not address questions of religious belief or the existence of God.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change, in a step-like manner, 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.
Darwin presented his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It claims that different species of organisms have a common ancestry, which can be determined through fossils and other evidence. This is the current view on evolution, which is supported in many scientific fields which include molecular biology.
Although scientists aren't able to determine exactly how organisms evolved, 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 than others to survive and reproduce. They pass on their genes on to the next generation. Over time, this results in a gradual accumulation of changes to the gene pool that gradually result in new species and types.
Some scientists use the term"evolution" to refer to large-scale changes, such the formation of an animal from an ancestral one. Some scientists, like population geneticists define evolution in a broader sense by talking about the net variation in the frequency of alleles over generations. Both definitions are accurate and acceptable, however some scientists argue that allele-frequency definitions miss important aspects of the evolution.
Origins of Life
The development of life is an essential stage in evolution. This occurs when living systems begin to evolve at a micro-level - within individual cells, for example.
The origins of life are an issue in a variety of disciplines that include biology, chemistry, and geology. The origin of life is a topic of interest in science, as it is a challenge to the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
The notion that life could be born 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 creation of living organisms was not possible through a natural process.
Many scientists still think it is possible to move from nonliving substances to living ones. However, the conditions that are required are extremely difficult to reproduce in a laboratory. This is why researchers studying the origins of life are also interested in determining the physical properties of the early Earth and other planets.
In addition, the development of life is dependent on the sequence of extremely complex chemical reactions that cannot be predicted based on basic physical laws alone. These include the transformation of long information-rich molecules (DNA or RNA) into proteins that carry out functions, and the replication of these complex molecules to create new DNA or RNA sequences. These chemical reactions are comparable to a chicken-and egg problem that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is essential for the beginning of life. But without life, the chemistry that is required to enable it is working.
Abiogenesis research requires collaboration between researchers from different disciplines. This includes prebiotic chemists astrobiologists, planetary scientists, geologists and geophysicists.
Evolutionary Changes
Today, the word evolution is used to describe general changes in genetic traits over time. These changes may result from the response to environmental pressures as explained in the article on Darwinism (see the entry on Charles Darwin for background) or natural selection.
This is a method that increases the frequency of those genes which confer an advantage in survival over other species which results in a gradual change in the overall appearance of a group. The specific mechanisms behind these changes in evolutionary process include mutation and reshuffling of genes in sexual reproduction, and gene flow between populations.
While reshuffling and mutations of genes occur in all organisms The process through which beneficial mutations become more common is referred to as natural selection. This is because, as mentioned above those with the advantageous trait are likely to have a higher reproductive rate than those who do not have it. Over the course of many generations, this differential in the number of offspring born can result in gradual changes in the amount of desirable characteristics in a particular population.
A good example of this is the growing 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 environment. These changes in the shape and form of organisms could also help create new species.
The majority of the changes that occur are caused by a single mutation, but occasionally, multiple mutations occur simultaneously. The majority of these changes are not harmful or even detrimental to the organism, but a small percentage can have a positive impact on survival and reproduction, thus increasing their frequency in the population over time. This is the process of natural selection, and it is able to be a time-consuming process that produces the cumulative changes that ultimately lead to the creation of a new species.
Many people think that evolution is a form of soft inheritance, which is the idea that inherited traits can be changed by deliberate choice or misuse. This is a misunderstanding of the biological processes that lead to the process of evolution. 에볼루션 is that evolution involves a two-step process, which involves the separate and often conflicting forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a species of mammal species which includes gorillas and chimpanzees. Our ancestral ancestors were walking on two legs, as shown by the oldest fossils. Biological and genetic similarities indicate that we have an intimate relationship with Chimpanzees. In fact, 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 lived between 8 and 6 million years ago.
Over time humans have developed a range of characteristics, including bipedalism as well as the use of fire. They also created advanced tools. It's only within the last 100,000 years that we have developed the majority of our important traits. These include language, a large brain, the capacity to build and use complex tools, and the ability to adapt to cultural differences.
Evolution occurs when genetic changes allow members of an organization to better adapt to the environment. Natural selection is the process that drives this change. Certain traits are preferred over others. Those with the better adaptations are more likely to pass their genes to the next generation. This is the process that evolves all species, and it is the basis of the theory of evolution.
Scientists call it the "law of natural selection." The law states that species that share an ancestor will tend to acquire similar traits as time passes. It is because these traits make it easier to reproduce and survive within their environment.
Every organism has a DNA molecule, which provides the information necessary to control their growth and development. The structure of DNA is composed of base pair arranged in a spiral around sugar and phosphate molecules. The sequence of bases in each strand determines the phenotype, the characteristic appearance and behavior of an individual. Different 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 found in Africa, Asia, and Europe. Although there are some differences, these fossils all support the idea that modern humans first appeared in Africa. The fossil evidence and genetic evidence suggest that early humans moved from Africa into Asia and then Europe.