The Berkeley Evolution Site
The Berkeley site has resources that can assist students and teachers learn about and teach evolution. The materials are arranged in different learning paths for example "What does T. rex look like?"
Charles Darwin's theory on natural selection explains how animals who are better equipped to adapt to changes in their environments over time, and those that don't disappear. 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." Scientifically, it is a term used to describe a change in the characteristics of living things (or species) over time. The reason for this change is biological terms on natural drift and selection.
Evolution is an important tenet in the field of biology today. It is a theory that has been tested and confirmed by a myriad of scientific tests. Evolution doesn't deal with the existence of God or religious beliefs like other theories in science, like the Copernican or germ theory of disease.
Early evolutionists, such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to evolve in a stepped-like manner over time. They called this 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.
Darwin published his theory of evolution in his book On the Origin of Species published in the early 1800s. It asserts that all species of organisms share an ancestry that can be traced through fossils and other evidence. This is the current view on evolution, which is supported in a wide range of disciplines that include molecular biology.
Scientists don't know the evolution of organisms but they are sure that natural selection and genetic drift is responsible for the evolution of life. People with traits that are advantageous are more likely to survive and reproduce, and they transmit their genes to the next generation. As time passes, the gene pool gradually changes and evolves into new species.
Some scientists also employ the term evolution to describe large-scale evolutionary changes, such as the formation of a new species from an ancestral species. Some scientists, like population geneticists define evolution in a more broad sense by talking about the net change in allele frequency over generations. Both definitions are valid and acceptable, however certain scientists argue that allele frequency definitions miss important aspects of the evolutionary process.
Origins of Life
One of the most crucial steps in evolution is the emergence of life. This happens when living systems begin to develop at the micro level - within cells, for instance.
The origin of life is an important issue in many disciplines, including biology and chemistry. The question of how living things got their start is a major topic in science because it is a major challenge to the theory of evolution. It is often described as "the mystery of life" or "abiogenesis."
Traditionally, the notion that life could emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a common belief before Louis Pasteur's research 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 move from nonliving substances to living ones. The conditions necessary to make life are not easy to reproduce in a lab. This is why scientists studying the nature of life are also keen to understand the physical properties of early Earth and other planets.
The life-cycle of a living organism is dependent on a number of complex chemical reactions, which are not predicted by the basic physical laws. These include the transformation of long information-rich molecules (DNA or RNA) into proteins that perform functions as well as the replication of these complex molecules to produce new DNA or RNA sequences. These chemical reactions can be compared to a chicken-and egg problem that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is required to begin the process of becoming a living organism. But, without life, the chemistry that is required to enable it is working.
Abiogenesis research requires collaboration with scientists from different fields. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
Today, the word evolution is used to describe the general changes in genetic traits over time. 에볼루션 바카라 무료 can be the result of adapting to environmental pressures, as explained in Darwinism.
This latter mechanism increases the frequency of genes that confer an advantage for survival in an animal, resulting in an overall change in the appearance of a group. The specific mechanisms responsible for these changes in evolutionary process include mutation or reshuffling genes during sexual reproduction, and also gene flow between populations.
While reshuffling and mutations of genes happen in all living things, 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 do not. This difference in the number of offspring produced over a number of generations could cause a gradual change in the average number advantageous traits in a group.
A good example of this is the growth of beak size on various species of finches found on the Galapagos Islands, which have developed beaks with different shapes to enable them to more easily access food in their new home. These changes in form and shape can aid in the creation of new organisms.
Most of the changes that take place are the result of one mutation, however sometimes, several changes occur at once. The majority of these changes are neutral or even detrimental to the organism, however, a small proportion of them can be beneficial to survival and reproduction, thus increasing the frequency of these changes in the population over time. This is the way of natural selection, and it can eventually result in the cumulative changes that eventually lead to the creation of a new species.
Some people confuse the idea of evolution with the idea that traits inherited can be altered through conscious choice or by use and abuse, a notion known as soft inheritance. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that trigger it. A more accurate description is that evolution involves a two-step process, which involves the separate and often antagonistic forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species that includes chimpanzees and gorillas. 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 the chimpanzees belonging to the Pan genus. This includes pygmy as well as bonobos. The last common ancestor between modern humans and chimpanzees was 8 to 6 million years old.
In the course of time humans have developed a number of characteristics, including bipedalism and the use of fire. They also invented advanced tools. It's only in the last 100,000 years that we have developed the majority of our essential traits. They include a huge brain that is complex and the capacity of humans to build and use tools, as well as cultural variety.
Evolution occurs when genetic changes allow individuals of a population to better adapt to their environment. Natural selection is the process that drives this change. Certain traits are preferred over others. People with 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 foundation of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species that have an ancestor in common will tend to acquire similar traits in the course of time. This is because these traits help them to live and reproduce in their environment.
All organisms have a DNA molecule that contains the information needed to control their growth and development. The DNA molecule is made up of base pairs that are arranged in a spiral around phosphate molecules and sugar molecules. The sequence of bases found in each string determines the phenotype or the characteristic appearance and behavior of an individual. Different mutations and reshuffling of the genetic material (known as alleles) during sexual reproduction cause variation in a group.
Fossils of the earliest human species, Homo erectus and Homo neanderthalensis were discovered in Africa, Asia, and Europe. Despite some differences, these fossils all support the idea 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.