“It is like confessing a murder” begins Charles Darwin, probably his most famous work. In fact, his theory of evolution revolutionized natural sciences. It also shook the prevailing worldview. In the mid-19th century, most people believed that God created the earth in 4004 BC. No species has evolved or been extinct since the birth of our planet according to this thesis.
- Theories of evolution
- Darwinism as a derogatory term
- Darwin’s Theory of evolution
- Evolution through natural selection
- Adaptation to the environment
- The long way to publication
- Basis of modern life sciences
- Evolution and genetics
Theories of evolution
In the 19th century scientists already accepted evolution as fact. Various theories explain the origin, development and diversity of living beings in a natural way. Basically, the term Darwinism is used to distinguish the content of Darwin’s theory from other theories. Such as Lamarckism, named after Jean-Baptiste Lamarck.
Darwin’s theory is based on inheritance, variability and natural selection. In this context, the term Darwinism is also used to emphasize the aspect of natural selection. This term was first described by Darwin and Wallace. It is used to draw a distinction Darwin’s theory of evolution and other discredited evolutionary theories. Theories such as Lamarckism or mutationism, which have only historical meaning.
Furthermore, the term Darwinism used by Wallace to emphasize the role of Charles Darwin as a pioneer of evolutionary research. Or, to differentiate between evolutionary mechanisms not mentioned by Darwin, such as gene drift and gene flow. These terms which are commonly used in modern synthetic theory of evolution were introduced later.
In this context it is important to mention Neo Darwinism. This is a theoretical system dating back to August Weismann, which represents a transitional stage between Darwinian and synthetic theory. This discipline was founded by Theodosius Dobzhansky and integrated into evolutionary biology.
Darwinism as a derogatory term
Opponents of evolutionary biology use the term Darwinism as a rather derogatory term for evolutionary sciences. They speak of evolution as a teaching or belief. The purpose of this is to demand the equal treatment of beliefs such as creationism or intelligent design. The derogatory term evolutionism is often used in the same context. This term has a different meaning in ethnology.
Darwin’s Theory of evolution
Charles Robert Darwin had another idea about the creation of life on Earth. In his book “On the Origin of Species” he published these ideas for the first time in 1859.
The book sold 1250 copies on the first day. The London Natural History Museum exhibits the book and numerous other related items.
Darwin’s theory consists of several assumptions:
- Reproduction: Individuals in a population always produce more offspring than would actually be necessary to preserve them.
- Variation: The individuals in a population are never the same. They differ in several traits.
- Selection (competition): Individuals who better adapt to the existing environmental conditions than others have a competitive advantage. As a result, they survive more often. And thus to they are able to pass their genes to the next generation.
- Inheritance: Individuals inherit variations in traits to a certain extent.
The term “evolution” does not appear in the first edition. Yet that is exactly what Darwin’s first main thesis is. It says that nature has developed gradually and God did not create it in 7 days.
Darwin supported this consideration with detailed scientific evidence he collected during his cruise with the HMS Beagle.
Evolution through natural selection
In his origin of species, Darwin claims that all life on earth has evolved from various primitive forms.
In this context, he presented two main theses:
- Species are constantly changing (evolving)
- Change is a result of natural selection
Darwin’s idea behind natural selection is simple. All life strives to multiply, but since resources are scarce in every habitat, not all organisms can do it. To increase the likelihood of survival, the individual species produce many offspring, not all of which can survive.
These offspring are all randomly endowed with different traits. Some individuals adapt to their environment better than others. These individuals manage to survive and reproduce.
In this way, the more adaptable features prevail automatically. Darwin called this “survival of the fittest”. By that he meant that the most adapted survives, not the strongest.
Adaptation to the environment
The adaptation to the respective living conditions can be different within one species. On the Galapagos Islands, Darwin observed that individual populations, develop independently of one another if they live far apart.
Certain types of finches and turtles, had adapted individually to the conditions on each island. For example, they developed characteristic beak and shell shapes.
During such adaptation process populations of a species develop so far apart that they eventually become different species. In other words, they can no longer reproduce with each other. Darwin also found examples of this in the Galapagos Islands.
The long way to publication
Darwin garthere overwhelming evidence over the course of his research life. Nevertheless, he was long uncertain whether he should publish his research results.
Finally, more than 20 years after returning from the expedition, he dared. After reading it, some celebrated Darwin as a revolutionary in natural sciences. However, as Darwin himself predicted in advance, most thought of him as a heretic and atheist.
Basis of modern life sciences
In fact, Darwin was not right in all of his assumptions about evolution. For example, the origin of life on Earth was not clear to him. Also, the so-called primordial soup did not occur in his theory.
In addition, Darwin did not trace all life on earth back to one origin. He believed that each large group of animals had its own starting point. That is, there are numerous archetypes.
In addition, scientists no longer accept his theory of heredity. However, no serious researcher doubts the principles of his work. Charles Darwin’s theory of the origin of species has long become the basis of modern life sciences.
Evolution and genetics
Genetics was a largely unexplored area in Darwin’s times. It was Ernst Mayr who brought Darwin’s concept of natural selection in line with modern genetics. Based on his research Mayr defined species as follows:
Groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups
That is to say that organisms of one species cannot produce offspring with organisms of another species. Otherwise, these offspring would not be fertile. For him, this isolation is the criterion to distinguish between two types.
Today, Richard Dawkins is the most radical representative of the evolution theory. Dawkins believes that genes are the central units of selection. They use the body only as a “propagation machine”. Dawkins campaigns against fundamentally Christian opponents of the theory. Because of this an Oxford theologian called him “Darwin’s Rottweiler”.
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