The Berkeley Evolution Site
The Berkeley site has resources that can help students and teachers learn about and teach evolution. The materials are arranged into different learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains how animals that are better equipped to adapt biologically to changing environment survive over time and those that do not disappear. Science is all about this process of evolutionary change.
What is Evolution?
The term "evolution" can have many nonscientific meanings, including "progress" or "descent with modification." It is scientifically based and is used to describe the process of change of characteristics over time in organisms or species. The reason for this change is biological terms on natural drift and selection.
Evolution is a central tenet of modern biology. It is a well-supported theory that has stood up to the test of time and a multitude of scientific tests. Contrary to other theories of science such as the Copernican theory or the germ theory of disease, the evolution theory is not a discussion of spiritual belief or God's existence.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics 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 idea in his Principles of Geology, first published in 1833.
Darwin presented his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It states that all species of organisms share an ancestry that can be traced by fossils and other evidence. This is the modern view of evolution, which is supported in a wide range of areas of science that include molecular biology.
While scientists do not know exactly how organisms evolved but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. People with desirable traits are more likely to survive and reproduce, and these individuals transmit their genes to the next generation. In time this leads to a gradual accumulation of changes to the gene pool that gradually result in new species and forms.
Some scientists employ the term evolution in reference to large-scale change, such as the development of a species from an ancestral one. Other scientists, such as population geneticists, define it more broadly by referring the net change in allele frequencies over generations. Both definitions are accurate and acceptable, however some scientists believe that allele-frequency definitions miss important aspects of the evolutionary process.
Origins of Life
The development of life is an essential step in evolution. This occurs when living systems begin to develop at the micro level, within individual cells, for instance.
The origin of life is an important topic in a variety of disciplines, including biology and chemistry. The question of how living organisms began is a major topic in science due to it being an enormous challenge to the theory of evolution. It is often called "the mystery of life" or "abiogenesis."
The notion that life could be born from non-living matter was known as "spontaneous generation" or "spontaneous evolutionary". It was a popular belief before Louis Pasteur's experiments proved that the creation of living organisms was not possible by the natural process.
Many scientists still believe that it is possible to make the transition from nonliving substances to life. The conditions necessary for the creation of life are difficult to reproduce in a lab. Researchers studying the beginnings of life are also keen to understand the physical properties of the early Earth and other planets.
The growth of life is also dependent on a series of complex chemical reactions which are not predicted by simple physical laws. This includes the conversion of long, information-rich molecules (DNA or RNA) into proteins that carry out a function and the replication of these intricate molecules to produce new DNA or RNA sequences. These chemical reactions can be compared with a chicken-and egg problem that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is essential for the onset life. But without life, the chemistry that is required to create it is working.
에볼루션 바카라 무료체험 requires collaboration with scientists from various fields. This includes prebiotic chemists the astrobiologists, the planet scientists geophysicists and geologists.
Evolutionary Changes
Today, the word evolution is used to describe gradual changes in genetic traits over time. These changes can result from adaptation to environmental pressures, as discussed in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
에볼루션 코리아 increases the number of genes that confer an advantage for survival in an animal, resulting in an overall change in the appearance of an entire group. 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 mutations of genes happen in all living organisms and the process by which beneficial mutations are more frequent is called natural selection. As mentioned above, those who possess the desirable trait have a higher reproductive rate than those who do not. Over the course of many generations, this difference in the number of offspring born can result in gradual changes in the amount of desirable traits within a group of.
This is evident in the evolution of different beak shapes on finches from the Galapagos Islands. They have developed these beaks in order that they can access food more quickly in their new home. These changes in the shape and appearance of living organisms may also aid in the creation of new species.
The majority of changes are caused by a single mutation, although sometimes multiple occur at the same time. Most of these changes may be negative or even harmful, but a small number could have a positive impact on survival and reproduce and increase their frequency over time. This is the mechanism of natural selection, and it is able to, over time, produce the cumulative changes that eventually lead to the creation of a new species.
Some people confuse the notion of evolution with the notion that inherited characteristics can be altered by conscious choice or by use and abuse, a notion known as soft inheritance. This is a misunderstanding of the biological processes that lead to evolution. It is more precise to say that evolution is a two-step, separate process, that is influenced by the forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates - a species of mammals that includes gorillas, chimpanzees, and bonobos. The earliest human fossils show that our ancestors were bipeds - walking on two legs. Genetic and biological similarities suggest that we are closely related to chimpanzees. In fact, our closest relatives are chimpanzees from the Pan genus. This includes pygmy and bonobos. The last common ancestor shared between modern humans and chimpanzees was 8 to 6 million years old.
As time has passed humans have developed a number of characteristics, such as bipedalism and the use of fire. They also developed advanced tools. It is only within the last 100,000 years that we've developed the majority of our important traits. They include language, a large brain, the ability to construct and use complex tools, as well as the ability to adapt to cultural differences.
Evolution occurs when genetic changes enable members of a group to better adapt to the environment. Natural selection is the mechanism that triggers this adaptation. Certain traits are preferred over others. The ones who are better adaptable are more likely to pass on their genes to the next generation. This is the process that evolves all species and forms the basis of the theory of evolution.
Scientists call it the "law of natural selection." The law states that species which have a common ancestor are more likely to develop similar traits over time. This is because the characteristics make it easier for them to survive and reproduce in their natural environment.
All organisms possess a DNA molecule that contains the information needed to guide their growth. The structure of DNA is made of base pairs which are 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 mutations and reshuffling of the genetic material (known as alleles) during reproduction causes variation in a group.
Fossils from the first human species, Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. Despite some differences the fossils all support the hypothesis that modern humans first came into existence in Africa. Genetic and fossil evidence also suggest that early humans came from Africa into Asia and then Europe.