The Berkeley Evolution Site
Teachers and students who visit the Berkeley site will find a wealth of resources to assist them in understanding and teaching evolution. The materials are arranged in various learning paths that can be used in a variety of ways like "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how creatures that are better equipped to adapt biologically to a changing environments survive longer and those that don't disappear. This process of biological evolution is what science is all about.
What is Evolution?
The word evolution can be used to refer to a variety of nonscientific meanings. For example it could refer to "progress" and "descent with modifications." Scientifically it refers to a changes in the traits of living things (or species) over time. This change is based in biological terms on natural selection and drift.
Evolution is the central tenet of modern biology. It is an established theory that has stood the test of time and a multitude of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, evolution is not a discussion of spiritual belief or the existence of God.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to change in a stepped-like manner over time. This was known 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 states that all species of organisms share common ancestors that can be traced by fossils and other evidence. This is the current understanding of evolution, and is supported by many research lines in science that include molecular genetics.
extra resources do not know how organisms evolved however they are certain that natural selection and genetic drift are responsible for the evolution of life. Individuals with advantageous traits are more likely to survive and reproduce, and these individuals transmit their genes to the next generation. As time passes this leads to a gradual accumulation of changes to the gene pool which gradually lead to new species and forms.
Some scientists also use the term"evolution" to refer to large-scale changes in evolutionary processes such as the creation of the new species from an ancestral species. Other scientists, such as population geneticists, define the term "evolution" more broadly by referring to a net change in the frequency of alleles across generations. Both definitions are acceptable and accurate, although some scientists argue that the allele-frequency definition is missing essential aspects of the evolution process.
Origins of Life
The birth of life is an essential stage in evolution. This occurs when living systems begin to evolve at the micro level - within individual cells, for example.
The origin of life is an important issue in a variety of fields that include biology and chemistry. The question of how living organisms began is of particular importance in science due to it being an enormous challenge to the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis."
The idea that life could arise from non-living things was called "spontaneous generation" or "spontaneous evolutionary". It was a popular belief prior to Louis Pasteur's experiments proved that the development of living organisms was not achievable through the natural process.
Many scientists believe that it is possible to go from nonliving substances to living. The conditions needed to make life are not easy to reproduce in a lab. Researchers studying the nature of life are also interested in determining the physical properties of early Earth and other planets.
Additionally, the evolution of life is dependent on a sequence of very complex chemical reactions that cannot be predicted from the fundamental physical laws on their own. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that carry out a function and the replication of these intricate molecules to generate new DNA or RNA sequences. These chemical reactions can be compared with the chicken-and-egg issue: the emergence and development of DNA/RNA, a protein-based cell machinery, is required for the onset life. But, without life, the chemistry that is required to make it possible is working.
Research in the area of abiogenesis requires collaboration among scientists from various fields. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
The word evolution is usually used today to refer to the accumulated changes in genetic characteristics of an entire population over time. These changes could be the result of adapting to environmental pressures, as explained in Darwinism.
The latter is a mechanism that increases the frequency of those genes in a species that confer a survival advantage over others, resulting in an ongoing change in the overall appearance of a group. These evolutionary changes are caused by mutations, reshuffling of genes in the process of sexual reproduction, and also by gene flow.
While reshuffling and mutation of genes are common in all living organisms, the process by which beneficial mutations are more frequent is referred to as natural selection. This is because, as noted above, those individuals with the beneficial trait tend to have a higher fertility rate than those who do not have it. Over many generations, this differential in the numbers of offspring born could result in an inclination towards a shift in the number of advantageous traits within a group of.
This is evident in the evolution of various beak shapes on finches from the Galapagos Islands. They have created these beaks to ensure that they can access food more quickly in their new home. These changes in form and shape can also help create new organisms.
Most of the changes that take place are the result of one mutation, however occasionally, multiple mutations occur simultaneously. Most of these changes can be neutral or even harmful however, a few may have a positive effect on survival and reproduction, increasing their frequency over time. Natural selection is a mechanism that can produce the accumulating change over time that leads to a new species.
Some people confuse the notion of evolution with the idea that inherited characteristics can be altered by conscious choice, or through use and abuse, a concept called soft inheritance. This is a misinterpretation of the nature of evolution and of the actual biological processes that cause it. It is more accurate to say that the process of evolution is a two-step, independent process, that is influenced by the forces of natural selection and mutation.
Origins of Humans
Humans today (Homo sapiens) evolved from primates - a group of mammals that also includes chimpanzees and gorillas and bonobos. The earliest human fossils prove that our ancestors were bipeds. They were walking on two legs. Biological and genetic similarities indicate that we have an intimate relationship with Chimpanzees. In fact, our closest relatives are chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. The last common ancestor shared between modern humans and chimpanzees was between 8 and 6 million years old.
As time has passed, humans have developed a variety of traits, including bipedalism and the use of fire. They also invented advanced tools. It is only within the last 100,000 years that we have developed the majority of our essential characteristics. These include language, a large brain, the ability to construct and use complex tools, and the diversity of our culture.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their surroundings. This adaptation is triggered by natural selection, which is a process by which certain traits are more desirable than others. People with better adaptations are more likely to pass their genes to the next generation. This is the way all species evolve, and the foundation for the theory of evolution.
Scientists refer to it as the "law of natural selection." The law states that species that have a common ancestor are more likely to develop similar traits over time. This is because these traits make it easier to survive and reproduce within their environment.
All organisms possess an molecule called DNA that holds the information needed to control their growth. The DNA molecule consists of base pairs that are arranged in a spiral around phosphate molecules and sugar molecules. Read More Listed here of bases within each strand determines the phenotype, the characteristic appearance and behavior of a person. Variations in changes and reshuffling of genetic material (known as alleles) during reproduction causes variation in a group.
Fossils from the earliest human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. Although there are some differences they all support the hypothesis 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.