The Berkeley Evolution Site
The Berkeley site has resources that can help students and educators understand and teach evolution. The materials are organized in various learning paths that can be used in a variety of ways like "What does T. rex look like?"
news on natural selection describes how species who are better equipped to adapt to changes in their environment survive over time and those who do not become extinct. This process of biological evolution is the main focus of science.
What is Evolution?
The term "evolution" can have many nonscientific meanings, including "progress" or "descent with modification." It is scientifically based and refers to the process of changing characteristics over time in organisms or species. In biological terms this change is based on natural selection and genetic drift.
Evolution is a central tenet of modern biology. It is an established theory that has stood up to the tests of time and thousands of scientific tests. In contrast to other theories in science, such as the Copernican theory or the germ theory of disease, the evolution theory does not address issues of spiritual belief or God's existence.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical characteristics were predetermined to change, in a step-like manner, over time. This was known 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.
In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It claims that different species of organisms have a common ancestry, which can be traced through fossils and other evidence. This is the current perspective on evolution, which is supported by a variety of areas of science that include molecular biology.
Although scientists aren't able to determine the exact mechanism by which organisms evolved but they are certain that the evolution of life on earth is the result of natural selection and genetic drift. People with desirable traits are more likely to survive and reproduce. They pass on their genes on to the next generation. In time, this results in an accumulation of changes to the gene pool, which eventually lead to new species and forms.
Some scientists use the term"evolution" in reference to large-scale change, such as the development of one species from an ancestral one. Other scientists, such as population geneticists, define the term "evolution" more broadly by referring to the net change in the frequency of alleles across generations. Both definitions are valid and reliable, although some scientists argue that the allele-frequency definition is missing crucial aspects of the evolutionary process.
Origins of Life
The development of life is a key step in the process of evolution. The beginning of life takes place when living systems begin to evolve at a micro scale, for instance within cells.
The origin of life is an important issue in a variety of fields, including biology and chemistry. The question of how living things started is a major topic in science since it poses an enormous challenge to the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
Traditionally, the idea that life can emerge from nonliving things 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 development of life to be a result of a purely natural process.
Many scientists believe it is possible to go from nonliving to living substances. However, the conditions that are required are extremely difficult to reproduce in the laboratory. This is why researchers studying the nature of life are also interested in determining the physical properties of the 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 basic physical laws. These include the reading and re-reading of complex molecules, like DNA or RNA, to produce proteins that perform a particular function. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is required for the onset life. Although without life, the chemistry needed to enable it appears to be working.
Research in the area of abiogenesis requires cooperation among scientists from various disciplines. This includes prebiotic chemists the astrobiologists, the planet scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" is typically used to describe the cumulative changes in the genetic characteristics of populations over time. These changes may be the result of adapting to environmental pressures, as discussed in Darwinism.
This latter mechanism increases the number of genes that offer the advantage of survival for a species, resulting in an overall change in the appearance of the group. These evolutionary changes are caused by mutations, reshuffling of genes during sexual reproduction, and gene flow.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo changes and reshuffles of genes. As previously mentioned, those who have the advantageous trait have a higher reproductive rate than those who don't. This variation in the number of offspring that are produced over many generations can result in a gradual change in the average number advantageous traits in the group.
One good example is the growing beak size on different species of finches in the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new home. news in the shape and form of organisms could also help create new species.
Most of the changes that occur are the result of one mutation, however occasionally, multiple mutations occur simultaneously. Most of these changes are neutral or even harmful to the organism, but a small percentage can have an advantageous impact on the survival of the organism and its reproduction, thereby increasing the frequency of these changes in the population over time. Natural selection is a mechanism that can produce the accumulating change over time that leads to the creation of a new species.
Many people think that evolution is a form of soft inheritance, which is the idea that traits inherited from parents can be changed by conscious choice or by abuse. This is a misunderstanding of the biological processes that lead to the process of evolution. It is more accurate to say that the process of evolution is a two-step independent process, which involves the forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo Sapiens) evolved from primates, which is a group of mammal species which includes chimpanzees and gorillas. Our ancestors walked on two legs, as shown by the oldest fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In actual fact, our closest relatives are chimpanzees from the Pan genus. This includes pygmy and bonobos. The last common ancestor of modern humans and chimpanzees lived between 8 and 6 million years ago.
Humans have evolved a variety of traits over time, including bipedalism, the use of fire, and the development of advanced tools. But it's only in the last 100,000 years or so that most of the characteristics that differentiate us from other species have emerged. These include language, large brain, the ability to build and use complex tools, and the ability to adapt to cultural differences.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their environment. Natural selection is the process that triggers this adaptation. Certain characteristics are more desirable than others. The ones with the best adaptations are more likely to pass 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 that have a common ancestor, tend to develop similar traits over time. This is because the characteristics make it easier for them to survive and reproduce in their environment.
Every organism has DNA molecules, which contains the information needed to direct their growth and development. The DNA molecule consists of base pairs arranged spirally around sugar molecules and phosphate molecules. The sequence of bases within each string determines the phenotype or the appearance and behavior of an individual. The variations in a population are caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the first human species, Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. Although there are some differences the fossils all support the hypothesis that modern humans first came into existence in Africa. The genetic and fossil evidence suggests that the first humans left Africa and migrated to Asia and Europe.