Teachers and students who visit the Berkeley site will find resources to aid in understanding and teaching evolution. The resources 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 adaptable to changing environments survive and those that are not extinct. Science is all about this process of evolution.
What is Evolution?
The word evolution can be used to refer to a variety of nonscientific meanings. For example, it can mean "progress" and "descent with modifications." It is scientifically based and refers to the process of changing traits over time in organisms or species. The reason for this change is biological terms on natural selection and drift.
Evolution is a key principle in the field of biology today. It is an accepted theory that has stood the test of time and thousands of scientific studies. Unlike many other scientific theories such as the Copernican theory or the germ theory of disease, evolution does not address questions of religion or the existence of God.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to evolve in a gradual manner 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.
In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It asserts that different species of organisms have a common ancestry, which can be traced through fossils and other evidence. This is the modern view on evolution, which is supported in a wide range of scientific fields, including molecular biology.
Scientists do not know how organisms evolved, but they are confident that natural selection and genetic drift are the reason for the evolution of life. People with desirable traits are more likely to survive and reproduce, and these individuals transmit their genes to the next generation. Over time this leads to gradual changes to the gene pool, which eventually result in new species and forms.
Some scientists also use the term evolution to describe large-scale evolutionary changes like the creation of the new species from an ancestral species. Other scientists, like population geneticists, define evolution more broadly, referring to the net variation in the frequency of alleles over generations. Both definitions are accurate and acceptable, however some scientists believe that allele-frequency definitions do not include important aspects of evolutionary process.
Origins of Life
The birth of life is an essential step in the process of evolution. This happens when living systems begin to develop at a micro-level - within individual cells, for instance.
The origins of life are a topic in many disciplines such as biology, chemistry and geology. The question of how living organisms began is of particular importance in science because it is a major 에볼루션 바카라 challenge to the theory of evolution. It is often described as "the mystery of life" or "abiogenesis."
Traditionally, the idea that life can arise from nonliving objects is known as spontaneous generation or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the emergence of life to be a result of the natural process.
Many scientists still believe that it is possible to go from nonliving substances to living. However, the conditions that are required are extremely difficult to reproduce in labs. Researchers studying the beginnings of life are also interested in determining the physical properties of early Earth and other planets.
The growth of life is also dependent on a series of complex chemical reactions which are not predicted by basic physical laws. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that perform functions, and the replication of these intricate molecules to produce new DNA or RNA sequences. These chemical reactions are comparable to the chicken-and-egg issue: the emergence and development of DNA/RNA, protein-based cell machinery, is required for the beginning of life. However, without life, the chemistry required to enable it is working.
Research in the field of abiogenesis requires collaboration between scientists from a variety of disciplines. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
Today, the word evolution is used to describe the gradual changes in genetic traits over time. These changes could result from adaptation to environmental pressures as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This process increases the number of genes that confer an advantage for survival in the species, leading to an overall change in the appearance of the group. These evolutionary changes are caused by mutations, reshuffling genes during sexual reproduction, and gene flow.
While mutation and reshuffling of genes occur in all living organisms and the process by which beneficial mutations are more prevalent is referred to as natural selection. As noted above, individuals with the beneficial trait have a higher reproduction rate than those who don't. This variation in the number of offspring produced over many generations can result in a gradual shift in the average number advantageous traits in a group.
This can be seen in the evolution of different beak shapes for finches from the Galapagos Islands. They have developed these beaks so they can get food more quickly in their new home. These changes in shape and form can aid in the creation of new organisms.The majority of the changes that take place are the result of one mutation, but occasionally several will happen simultaneously. Most of these changes can be neutral or even harmful however, a small percentage may have a positive effect on the survival of the species and reproduce and increase their frequency over time. This is the mechanism of natural selection and it can, over time, produce the gradual 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 altered by deliberate choice or misuse. 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 involves the forces of natural selection and mutation.
Origins of Humans
Humans today (Homo sapiens) evolved from primates, a group of mammals that includes chimpanzees and gorillas and bonobos. Our ancestral ancestors were walking on two legs, as shown by the oldest fossils. Genetic and biological similarities suggest that we share a close relationship with the chimpanzees. In reality we are the most closely with chimpanzees in the Pan Genus which includes bonobos and pygmy-chimpanzees. The last common ancestor of modern humans and chimpanzees was born between 8 and 6 million years ago.
Humans have developed a range of traits throughout time including bipedalism, the use of fire, and the development of advanced tools. It is only in the last 100,000 years or so that the majority of the traits that distinguish us from other species have developed. These include a big brain that is complex, the ability of humans to build and use tools, and the diversity of our culture.
Evolution occurs when genetic changes allow members of a population to better adapt to their environment. Natural selection is the mechanism that triggers this adaptation. Certain traits are preferred over others. People with better adaptations are more likely to pass their genes to the next generation. This is how all species evolve, and the basis of the theory of evolution.
Scientists call it the "law of Natural Selection." The law says that species that share a common ancestor tend to develop similar traits over time. This is because the characteristics make it easier for them to live and reproduce in their natural environment.Every living thing has the DNA molecule, which contains the information needed to guide their growth. The DNA molecule consists of base pairs arranged spirally around sugar molecules and phosphate molecules. The sequence of bases in each string determines the phenotype or the distinctive appearance and behavior of a person. A variety of changes and reshuffling of genetic material (known as alleles) during sexual reproduction cause variations in a population.
Fossils from the earliest human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. Although there are some differences the fossils all support the notion that modern humans first came into existence in Africa. The evidence from fossils and genetics suggests that the first humans left Africa and moved to Asia and Europe.
