The Berkeley Evolution Site
The Berkeley site has resources that can assist students and teachers understand and teach evolution. The materials are organized in different learning paths, such as "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how over time creatures that are better able to adapt biologically to changing environments do better than those that don't become extinct. Science is all about this process of biological evolutionary change.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings, including "progress" or "descent with modification." It is a scientific 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 a key tenet in the field of biology today. It is an established theory that has stood the test of time and thousands of scientific tests. It does not address God's presence or spiritual beliefs in the same way as other theories in science, like the Copernican or germ theory of diseases.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change, in a gradual way, 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 asserts that all species of organisms have an ancestry that can be traced through fossils and other evidence. This is the current view on evolution, which is supported in many scientific fields which include molecular biology.
Scientists aren't sure how organisms evolved however they are certain that natural selection and genetic drift are the primary reason for the evolution of life. Individuals with advantageous characteristics are more likely than others to live and reproduce. They transmit their genes to the next generation. As time passes, this results in a gradual accumulation of changes to the gene pool that gradually result in new species and forms.
Certain scientists use the term"evolution" to refer to large-scale change, such as the development of an animal from an ancestral one. Some scientists, like population geneticists, define evolution in a broad sense, referring to the net variation in the frequency of alleles over generations. Both definitions are valid and reliable however, some scientists claim that the definition of allele frequency is lacking crucial aspects of the evolutionary process.
Origins of Life
The birth of life is a key step in evolution. The beginning of life takes place when living systems start to evolve at a micro scale, for instance within individual cells.
The origin of life is an important issue in many fields such as biology and the field of chemistry. The question of how living things started is a major topic in science because it is an important challenge to the theory of evolution. 에볼루션코리아 is sometimes referred to "the mystery" of life or "abiogenesis."
Traditionally, the belief 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 creation of life to be a result of a purely natural process.
Many scientists still think it is possible to go from nonliving to living substances. However, the conditions needed are extremely difficult to reproduce in a laboratory. Researchers investigating the beginnings of life are also interested in determining the physical properties of the early Earth and other planets.
The growth of life is dependent on a number of complex chemical reactions that are not predicted by simple physical laws. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that perform some function, and the replication of these complex molecules to create new DNA or sequences of RNA. These chemical reactions are comparable to a chicken-and egg problem: the emergence and development of DNA/RNA, protein-based cell machinery, is essential for the beginning of life. However, without life, the chemistry that is required to create it does appear to work.
Research in the area of abiogenesis requires cooperation among scientists from a variety of disciplines. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
The term "evolution" is commonly used to describe the cumulative changes in the genetic traits of a population over time. These changes can result from adaptation to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background) or natural selection.
This is a method that increases the frequency of genes that confer an advantage in survival over other species which results in an ongoing change in the overall appearance of a group. These evolutionary changes are triggered by mutations, reshuffling genes during sexual reproduction and the flow of genes.
While reshuffling and mutations of genes happen in all living things, the process by which beneficial mutations are more prevalent is known as natural selection. visit website happens because, as mentioned above, those individuals with the beneficial trait tend to have a higher reproductive rate than those who do not have it. This variation in the number of offspring that are produced over a number of generations could result in a gradual shift in the average number advantageous traits within the group.
This is evident in the evolution of various beak designs on finches that are found in the Galapagos Islands. They have developed these beaks so they can get food more easily in their new habitat. These changes in the shape and appearance of organisms can also aid in the creation of new species.
Most of the changes that occur are caused by one mutation, but occasionally several will happen simultaneously. Most of these changes can be negative or even harmful however, a small percentage may have a positive effect on survival and reproduction and increase their frequency over time. This is the way of natural selection and it can be a time-consuming process that produces the gradual changes that eventually lead to the creation of a new species.
Many people confuse the concept of evolution with the idea that the traits inherited from parents can be altered by conscious choice or use and abuse, which is known as soft inheritance. This is a misinterpretation of the biological processes that lead to the process of evolution. A more accurate description is that evolution is a two-step process involving the independent and often conflicting forces of mutation and natural selection.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates - a group of mammals that also includes chimpanzees, gorillas, and bonobos. Info walked on two legs, as evidenced by the first fossils. Genetic and biological similarities suggest that we are closely related to chimpanzees. In reality we are the most closely related to the chimpanzees within the Pan genus that includes pygmy and bonobos and pygmy chimpanzees. The last common ancestor shared between humans and chimpanzees was 8 to 6 million years old.
As time has passed humans have developed a variety of traits, including bipedalism and the use of fire. They also developed advanced tools. It's only within the last 100,000 years that we've developed the majority of our important traits. These include language, large brain, the ability to build and use complex tools, and cultural diversity.
The process of evolution occurs when genetic changes allow members of an organization to better adapt to their environment. This adaptation is triggered by natural selection, a process whereby certain traits are more desirable than other traits. The ones who are better adjusted are more likely to pass on their genes to the next generation. This is how all species evolve and is the basis for 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 traits over time. This is because these characteristics make it easier for them to survive and reproduce in their environment.
All organisms possess a DNA molecule that contains the information needed to control their growth. The DNA structure is composed of base pairs arranged in a spiral around phosphate and sugar molecules. The sequence of bases found in each strand determines the phenotype - the appearance and behavior of a person. Variations in changes and reshuffling of genetic material (known as alleles) during sexual reproduction cause variation in a population.
Fossils from the early human species Homo erectus, as well as Homo neanderthalensis have been found in Africa, Asia and Europe. Despite some differences they all support the notion that modern humans first came into existence in Africa. The genetic and fossil evidence suggests that early humans left Africa and migrated to Asia and Europe.