The Berkeley Evolution Site
Teachers and students who visit the Berkeley site will find resources to help them understand and teach evolution. The resources are organized into optional learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains that over time, animals that are better able to adapt biologically to changing environments thrive, and those that are not extinct. This process of evolution is the main focus of science.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings, such as "progress" or "descent with modification." It is an academic term that refers to the process of change of characteristics over time in organisms or species. The reason for this change is biological terms on natural selection and drift.
Evolution is the central tenet of modern biology. It is a well-supported theory that has withstood the test of time and thousands of scientific studies. It does not address God's presence or spiritual beliefs, unlike many 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 characteristics were predetermined to change in a step-like fashion over time. This was called the "Ladder of Nature" or scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
Darwin revealed his theory of evolution in his book On the Origin of Species published in the early 1800s. It asserts that all species of organisms have a common ancestry which can be traced using fossils and other evidence. This is the modern view of evolution that is supported by numerous lines of scientific research that include molecular genetics.
While scientists do not know the exact mechanism by which organisms evolved but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. People with advantages are more likely than others to live and reproduce. They transmit their genes to the next generation. As time passes, the gene pool gradually changes and develops into new species.
Certain scientists use the term evolution in reference to large-scale changes, such the formation of a species from an ancestral one. Other scientists, such as population geneticists, define evolution more broadly, referring to a net change in allele frequencies over generations. Both definitions are acceptable and precise, although some scientists argue that the allele-frequency definition is missing essential aspects of the evolution process.
Origins of Life
The development of life is an essential step in the process of evolution. This occurs when living systems begin to develop at a micro-level - within cells, for instance.
The origins of life are an important issue in many areas that include biology and chemical. The origin of life is a subject of interest in science because it challenges the theory of evolution. It is often described as "the mystery of life" or "abiogenesis."
Traditionally, the idea that life can emerge from nonliving things is called spontaneous generation, or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments showed that it was impossible for the emergence of life to be a result of an entirely natural process.
Many scientists still think it is possible to go from nonliving to living substances. The conditions required to make life are not easy to replicate in a laboratory. This is why scientists investigating the origins of life are also keen to understand the physical properties of early Earth and other planets.
Furthermore, the growth of life is dependent on the sequence of extremely complex chemical reactions that can't be predicted from basic physical laws on their own. These include the reading and the replication of complex molecules, like DNA or RNA, to produce proteins that perform a particular function. These chemical reactions can be compared to the chicken-and-egg problem that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is essential for the onset life. However, without life, the chemistry that is required to make it possible is working.
Abiogenesis research requires collaboration between researchers from different disciplines. This includes prebiotic chemists, planet scientists, astrobiologists geophysicists, geologists, and geophysicists.
Evolutionary Changes
Today, the word evolution is used to describe cumulative changes in genetic characteristics over time. These changes may be the result of the adaptation to environmental pressures as described in Darwinism.
This latter mechanism increases the number of genes that provide a survival advantage in an animal, resulting in an overall change in the appearance of an entire group. These evolutionary changes are triggered by mutations, reshuffling of genes during sexual reproduction and the flow of genes.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo mutations and reshuffles in their genes. This is because, as noted above those with the beneficial trait tend to have a higher reproduction rate than those who do not have it. Over 무료에볼루션 of many generations, this variation in the numbers of offspring born could result in gradual changes in the average number of beneficial traits in a population.
One good example is the growth of beak size on different species of finches on the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new environment. These changes in the shape and appearance of living organisms may also be a catalyst for the creation of new species.
The majority of changes are caused by one mutation, but sometimes several occur at the same time. Most of these changes may be neutral or even harmful however, a small percentage could have a positive impact on survival and reproduction with increasing frequency as time passes. Natural selection is a mechanism that could result in the accumulation of change over time that leads to a new species.
Some people confuse the idea of evolution with the idea that inherited characteristics can be changed through conscious choice, or through use and abuse, a concept called soft inheritance. This is a misinterpretation of the biological processes that lead up to evolution. A more accurate description is that evolution is a two-step procedure that involves the distinct, and often competing, forces of mutation and natural selection.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, which is a group of mammal species which includes gorillas and chimpanzees. Our ancestral ancestors were walking on two legs, as shown by the oldest fossils. Genetic and biological similarities suggest that we have an intimate relationship with chimpanzees. In fact, our closest relatives are the chimpanzees of the Pan genus. This includes pygmy and bonobos. The last common ancestor of modern humans and chimpanzees was 8 to 6 million years old.
In the course of time humans have developed a number of characteristics, such as bipedalism and the use of fire. They also invented advanced tools. It's only in the last 100,000 years that we've developed the majority of our important traits. These include a large brain that is complex human ability to build and use tools, and cultural diversity.
무료에볼루션 of evolution occurs when genetic changes allow members of the group to better adapt to the environment. Natural selection is the process that triggers this adaptation. Certain characteristics are more desirable than others. The ones who are better adapted are more likely to pass their genes on to the next generation. This is the way all species evolve and is the basis of the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species which have a common ancestor are likely to develop similar characteristics over time. This is because these traits help them to reproduce and survive within their environment.
Every living thing has a DNA molecule that contains the information necessary to direct their growth. The structure of DNA is composed of base pair which are arranged in a spiral, around sugar and phosphate molecules. The sequence of bases in each string determines the phenotype or the distinctive appearance and behavior of an individual. Variations in mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction can cause variation in a population.
Fossils of the first human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. Although there are some differences they all support the idea 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.