The Berkeley Evolution Site
The Berkeley site has resources that can help students and teachers understand and teach evolution. The resources are organized into different learning paths for example "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how over time, animals that are better able to adapt biologically to changing environments do better than those that are not extinct. This process of evolution is what science is all about.
What is Evolution?
The word evolution can have many nonscientific meanings. For instance it could refer to "progress" and "descent with modifications." It is a scientific term that refers to the process of change of characteristics over time in organisms or species. This change is based in biological terms on natural selection and drift.
Evolution is an important concept in modern biology. It is a theory that has been verified by a myriad of scientific tests. Contrary to other theories of science, such as the Copernican theory or the germ theory of disease, evolution does not address issues of religion or God's existence.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical characteristics were predetermined to change, in a gradual manner, as time passes. This was referred to as 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 states that all species of organisms have a common ancestry which can be traced through fossils and other evidence. This is the modern view of evolution, which is supported by a variety of areas of science, including molecular biology.
Scientists aren't sure the evolution of organisms but they are sure that natural selection and genetic drift is responsible for the evolution of life. Individuals with advantageous characteristics are more likely to survive and reproduce. They then pass their genes on to the next generation. In time this leads to gradual changes in the gene pool that gradually result in new species and types.
Some scientists also employ the term"evolution" to describe large-scale evolutionary changes such as the creation of the new species from an ancestral species. Certain scientists, such as population geneticists, define evolution in a more broad sense by using the term "net change" to refer to the change in the frequency of alleles across generations. Both definitions are acceptable and precise however, some scientists claim that the allele-frequency definition is missing essential aspects of the evolution process.
Origins of Life
The birth of life is an essential step in the process of evolution. This occurs when living systems begin to develop at the micro level, within cells, for example.
The origin of life is a topic in many disciplines that include biology, chemistry, and geology. The origin of life is an area of great interest in science because it challenges the theory of evolution. It is often called "the mystery of life" or "abiogenesis."
Traditionally, the belief that life could emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a popular view before Louis Pasteur's experiments proved that it was impossible for the development of life to be a result of a purely natural process.
Many scientists still believe that it is possible to go from nonliving substances to living. The conditions required for the creation of life are difficult to replicate in a laboratory. Researchers who are interested in the origins and development of life are also eager to know the physical properties of the early Earth as well as other planets.
The life-cycle of a living organism is also dependent on a series of complex chemical reactions, which cannot be predicted by basic physical laws. These include the reading and the replication of complex molecules, like DNA or RNA, to produce proteins that perform a specific function. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is necessary for the onset life. Although, without life, the chemistry needed to make it possible does appear to work.
Research in the area of abiogenesis requires collaboration among scientists from a variety of disciplines. This includes prebiotic scientists, astrobiologists, and planet scientists.
Evolutionary Changes
The term "evolution" is used to describe the general changes in genetic traits over time. These changes could be the result of the adaptation to environmental pressures as explained in Darwinism.
This is a process that increases the frequency of genes in a species that confer an advantage in survival over others and causes an ongoing change in the overall appearance of a group. These changes in evolutionary patterns are caused by mutations, reshuffling of genes during sexual reproduction, and gene flow.
Natural selection is the process that allows beneficial mutations to become more common. 에볼루션바카라 undergo mutations and reshuffles of genes. As previously mentioned, those who have the advantageous trait have a higher reproductive rate than those that do not. This difference in the number of offspring produced over a long period of time can result in a gradual change in the number of advantageous traits within the group.
This is evident in the evolution of various beak shapes on finches from the Galapagos Islands. They have developed these beaks so they can get food more quickly in their new home. These changes in the shape and appearance of organisms can also help create new species.
The majority of the changes that occur are caused by one mutation, but sometimes, several changes occur at once. The majority of these changes are not harmful or even detrimental to the organism, however a small portion of them could have a positive impact on survival and reproduction, thus increasing the frequency of these changes in the population over time. This is the mechanism of natural selection and it could, over time, produce the gradual changes that ultimately lead to the creation of a new species.
Many people confuse the concept of evolution with the notion that inherited characteristics can be altered through conscious choice, or through use and abuse, a concept known as soft inheritance. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that cause it. It is more precise to say that evolution is a two-step independent process that involves the forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates - a group of mammals that also includes gorillas, chimpanzees, and bonobos. Our ancestors walked on two legs, as evidenced by the oldest fossils. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In reality our closest relatives are chimpanzees from the Pan genus. This includes pygmy as well as bonobos. The last common ancestor of modern humans and chimpanzees dated 8 to 6 million years old.
In the course of time, humans have developed a number of characteristics, such as bipedalism as well as the use of fire. They also developed advanced tools. However, it is only in the past 100,000 years or so that the majority of the important characteristics that differentiate us from other species have developed. They include a huge brain that is complex and the capacity of humans to create and use tools, and cultural diversity.
The process of evolution is when genetic changes allow members of a group to better adapt to their environment. Natural selection is the process that triggers this adaptation. Certain traits are preferred over others. The better adjusted are more likely to pass on their genes to the next generation. This is how all species evolve, and the foundation for the theory of evolution.
Scientists call it the "law of Natural Selection." The law states that species which share a common ancestor tend to develop similar traits over time. This is because these characteristics make it easier for them to survive and reproduce in their environment.
Every organism has a DNA molecule that contains the information needed to control their growth. The structure of DNA is composed of base pairs which are arranged in a spiral, around phosphate and sugar molecules. The sequence of bases within each strand determines the phenotype - the characteristic appearance and behavior of an individual. Variations in a population can be caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the first human species, Homo erectus, and Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite some variations in their appearance, all support the hypothesis of modern humans' origins in Africa. The genetic and fossil evidence suggests that early humans left Africa and moved to Asia and Europe.