The Evolution Site
The theory of evolution by natural selection is the unifying force of modern biology. It ties together disciplines such as genetics, microbiology, and Palaeontology.
The study of evolution can be controversial and the misinformation that is generated can lead to confusion about its basic concepts. This Web site helps to clarify the fundamental concepts.
What is Evolution?
Modern evolutionary theory focuses on the gradual and cumulative changes that occur in populations over time. These changes are the result of natural selection. This is a process that increases the number organisms with beneficial traits, which enable them to survive and reproduce in specific environments. These organisms produce more offspring as a result of their positive characteristics. This can lead to a genetic mutation that could eventually lead to new species.
The term "evolution" is usually associated with "survival-of-the best" which means that those who are better adjusted to certain conditions will have an advantage over those less well-adapted. This is only one of the many ways in which evolution can occur.
Another way that the term "evolution" is used to suggest that a species will invariably progress from one state to the next one. This view of evolution can be described as anagenetic, or cladogenesis. This theory is not supported by the definition of evolution in science. Instead the theory of evolution that is scientifically based is based on the changes that take place within populations over time and these changes are the result of mutations that produce genomic variation and natural selection.
Some scientists, such as the great Charles Darwin, advocated this theory of evolution. Others, notably Alfred Russel Wallace, who created the macroevolution theory and believed that this was the only way the higher forms of life could be derived from lower forms.
A concept must be able stand up to rigorous tests and evidence to be considered as a theory. Evolution has stood the test of time and has been backed by numerous scientific disciplines ranging from geology to biology, the sciences of astronomy to chemistry. Evolution is a cornerstone of science and is believed by the majority of scientists across the world. Many people have misconceptions regarding the nature of the evolution theory and how it connects with religion.
What is the Theory of Evolution?
Evolution is the scientific explanation for how living things change over time. It is based upon a few well-established facts: that many more offspring are born than can survive as individuals differ in their physical traits and they can pass on traits to the next generation. These findings are backed by a growing body of evidence from molecular biology, palaeontology and climatology functional geology and morphology.
The theory of evolution through natural selection was conceived independently by Charles Darwin and Alfred Russel Wallace in the late 19th century as an explanation for the reason that organisms are adapted to their physical and biological environment. It is the most widely supported and validated theory in science. Its predictions were proved by the fact that for instance, more complex organisms have less genetic mutations. The more successful an organism is in terms of survival and reproducing, the more likely it will pass its genes on to future generations.
Some people oppose evolution because they believe it implies that there is no purpose to life. Many scientists who are religious believers such as the Cambridge palaeontologist Simon Conway Morris (BioLogos, 2014) believe that evolution is compatible with faith in God and is even enhanced by it.
In actual fact, a significant number of highly trained evolutionary biologists, including some who are revered evangelical Christian leaders have been involved in the creation and testing of the theory of evolution. Many of these researchers have contributed to the understanding of a wide variety of phenomena, such as phylogenetics, genomics, and the development and function of fossils.
The term "theory" is often used to refer to an assumption or speculation, when in fact it refers to a scientific idea that has been systematically tested and refined over time. Scientists test their theories by repeating the experiments or observations that led to them. Thus, the theory of evolution has been repeatedly tested out, as have the related theories of Copernican, germ and atomic theory.
What is the Process of Evolution?
The process of evolution is a gradual shift in the genetically different individuals within a species over time. This is the result of natural selection, which favors individuals who are better adapted to their environment. The more adapted individuals have a better chance of survival and reproduction. As more of these people survive and reproduce their genes, they become more common in the population. This process is sometimes described as "survival of the fittest."
According to the theory of evolution the mutations that cause genetic variation are the basic material for evolution. These mutations could occur at random, or under the influence of the environment. If mutations occur in a random manner, the allele frequencies can vary from generation-to-generation. If a mutation is beneficial, it will increase the allele frequency and cause the allele to be spread across the population.
Over time, these shifts in the frequencies of alleles can result in the creation of new species. The new species will evolve and develop into newer forms. This is a process known as macroevolution. The formation of an entirely new species is typically due to changes in the environment which provide certain types of resources available or create new environmental challenges. For instance, the rise of finches in the Galapagos Islands is a result of the abundance of food sources and the need to protect themselves from predators.
In a larger sense the term "evolution" can be described as any change in the nature of living organisms over time. The change could be subtle, like the development of a new color or a dramatic change, such as the development of an organ.
Scientists who accept the theory of evolution generally recognize the importance of genetic change in generating evolution. They also agree that evolution is a process that takes place over time, typically over millions of years. However, they differ on the role of various factors in speeding or slowing the process, like the role of environmental pressures, sexual selection, and mutation bias. Despite these differences most scientists still believe that evolution is real and the evidence to support this is overwhelming.
What is the Evidence of Evolution?
Throughout the years since Darwin's time, scientists have gathered evidence to support his theory of evolution. Some of this evidence comes from fossils, which demonstrate the changing features of living organisms over time. Similarities between living organisms as well as embryology, biogeography and genetics are further evidence.
The main proof of evolution is found in the evolutionary tree, which shows how different species are connected. Another source of evidence is homologous structures, which share a similar structure in different species, but have distinct functions such as the wings of birds and bats. The fact that different species develop and adapt to the same environment is also a sign of evolution. For example, arctic foxes and ptarmigans grow white fur coats that blend in with snow and ice. This is a form of convergent evolution, which suggests that the species have common ancestors.
Another evidence point is vestigial structures, which are unusable organs that could serve a purpose in a distant ancestor. The human appendix for instance is an odour from an organ that was once used to digest food. These structures tend to shrink in size once they are no longer utilized which is a process referred to as natural selection.
Scientists have also collected other evidence for evolution through observation and experimentation. The evidence for evolution can be grouped into six different categories: directly observable changes at a smaller scale, biogeographic distributions, comparative anatomies, the fossil record and genetics. Each of these provides convincing evidence that evolution of life took place.
Many people have misconceptions about the theory of evolution. But, it's a fact. It is not only a theory, it is a powerful collection of decades of observations and data that has been proven and tested. No matter what people believe or deny about the theory of evolution scientists continue to study and collect new data to better understand the history of life on Earth. This information will allow scientists to better understand how we can avoid future global catastrophes and how to best utilize the resources of our planet. This information will also help us better meet the needs and wants of all the people living on this planet.