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 organized 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 changing environment survive over time and those who do not end up becoming extinct. Science is all about this process of biological evolution.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings. For instance "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 one of the fundamental tenets of modern biology. It is a concept that has been tested and confirmed by thousands of scientific tests. In contrast to other theories in science, such as the Copernican theory or the germ theory of disease, evolution does not address questions of religious belief or God's existence.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change in a step-like manner, as time passes. 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 revealed his theory of evolution in his book On the Origin of Species published in the early 1800s. It asserts that different species of organisms have an ancestry that can be proven through fossils and other evidence. This is the modern view of evolution, which is supported by numerous research lines in science which includes molecular genetics.
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 advantages are more likely than others to survive and reproduce. They pass on their genes on to the next generation. As time passes the gene pool gradually changes and evolves into new species.
Some scientists use the term"evolution" in reference to large-scale changes, such the evolution of one species from an ancestral one. Certain scientists, such as population geneticists, define the term "evolution" in a broad sense, using the term "net change" to refer to the change in the frequency of alleles across generations. Both definitions are correct and palatable, but some scientists argue that allele-frequency definitions miss important aspects of the evolutionary process.
Origins of Life
The development of life is a key step in evolution. The beginning of life takes place when living systems begin to develop at a micro level, like within individual cells.
The origins of life are a topic in many disciplines such as biology, chemistry and geology. The question of how living organisms began has a special place in science since it poses an enormous challenge to the theory of evolution. It is sometimes referred to as "the mystery" of life or "abiogenesis."
The idea that life could be born from non-living things was called "spontaneous generation" or "spontaneous evolutionary". This was a popular belief before Louis Pasteur's tests showed that the development of living organisms was not possible by a natural process.
Many scientists believe that it is possible to transition from nonliving materials to living. The conditions needed to make life are not easy to replicate in a laboratory. Researchers investigating the beginnings of life are also interested in determining the physical properties of early Earth and other planets.
In addition, the development of life is a sequence of very complex chemical reactions that cannot be predicted based on basic physical laws alone. 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 create new DNA or sequences of RNA. These chemical reactions are often compared to the chicken-and-egg problem of how life came into existence in the first place. The development of DNA/RNA as well as proteins-based cell machinery is vital to the birth of life, however, without the emergence of life, the chemistry that makes it possible does not appear to work.
Research in the field 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 word evolution is usually used to refer to the accumulated changes in genetic characteristics of a 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 genes that confer an advantage in survival over other species and causes gradual changes in the overall appearance of a population. The specific mechanisms behind these evolutionary changes are mutation or reshuffling genes during sexual reproduction, and gene flow between populations.
While reshuffling and mutations of genes happen in all living things and the process by which beneficial mutations become more common is referred to as natural selection. As noted above, individuals with the beneficial trait have a higher reproductive rate than those who don't. This variation in the number of offspring produced over a long period of time can result in a gradual change in the number of advantageous characteristics in a group.
An excellent example is the growth of beak size on different species of finches in the Galapagos Islands, which have developed different beak shapes that allow them to easily access food in their new habitat. These changes in the shape and form of living organisms may also be a catalyst for the creation of new species.
Most of the changes that occur are caused by a single mutation, but occasionally several will happen at the same time. Most of these changes are not harmful or even detrimental to the organism, however, a small proportion of them can have a positive impact on the survival of the organism and its reproduction, thereby increasing their frequency in the population over time. This is the process of natural selection, and it could eventually result in the cumulative changes that ultimately lead to a new species.
Some people mistakenly associate evolution with the concept of soft inheritance that is the belief that traits inherited from parents can be changed by deliberate choice or misuse. 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 evolution is a two-step independent process, which involves the forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, which is a group of mammal species that includes gorillas and chimpanzees. Our predecessors walked on two legs, as shown by the earliest fossils. Biological and genetic similarities indicate that we have an intimate relationship with Chimpanzees. In actual fact our closest relatives are the chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. extra resources of humans and chimpanzees was between 8 and 6 million years old.
As time has passed humans have developed a variety of characteristics, including bipedalism as well as the use of fire. They also created advanced tools. It is only in the last 100,000 years or so that the majority of the essential characteristics that differentiate us from other species have emerged. These include language, large brain, the ability to create and utilize complex tools, and cultural diversity.
The process of evolution occurs when genetic changes allow individuals in a group to better adapt to their surroundings. Natural selection is the process that drives this change. Certain traits are preferred over others. The better adapted are more likely to pass on their genes to the next generation. This is the way that all species evolve and is the foundation of the theory of evolution.
Scientists call it the "law of natural selection." The law says that species that have a common ancestor, tend to develop similar traits over time. This is because these traits allow them to live and reproduce in their environments.
All organisms have DNA molecules, which is the source of information that helps control their growth and development. The DNA molecule is made up of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases within each strand determines phenotype, or the individual's characteristic appearance and behavior. Variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the earliest human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. These fossils, despite a few variations in their appearance, all support the theory that modern humans' ancestors originated in Africa. The fossil evidence and genetic evidence suggest that early humans migrated out of Africa into Asia and then Europe.