Over the centuries, many scientific discoveries have emerged, but few ideas have had a more deep and lasting impact on our understanding of life on Earth than Charles Darwin’s theory of evolution. Born from careful observations, thoughtful reflections, and precise ideas, Darwin’s theory revolutionized biology and forever changed the way we view the world.
More than a century and a half after publishing his theory, Darwin’s ideas continue to form the foundations of modern science, in fields far beyond biology. keep reading to learn more about Darwin’s theory.
Darwin’s Theory – The Theory of Evolution
Charles Darwin, the 19th – century English naturalist, extensively studied nature for more than 20 years. He collected notes about the distribution of animals and the relationship between living and extinct animals. It was finally found that current living animals share similarities to some extent not only between themselves but also with other species that existed millions of years ago, including those that became extinct!
Charles Darwin is known as the “Father of Evolution” due to his contribution to building the theory of evolution. His theory helped refute all traditional ancient beliefs that the formation of different species was a supernatural phenomenon. Rather, Darwin’s evolutionary theory of natural selection gave a more rational explanation for the formation of new species. According to natural selection, different species have arisen from a single species as a result of coping with a changing environment.
Darwin’s Theory – Natural Selection
Darwin had the following ideas regarding the theory of natural selection:
- Species continue to evolve or change over time. As the environment changes, the organism’s requirements also change and it adapts to the new environment. The phenomenon of change over a period of time according to natural requirements is known as coping.
- According to Darwin’s theory, only superior changes are obtained naturally, and inferior changes are eliminated. Therefore, not all Copings contribute to gradual evolution. For example, people who live in tropical countries have more melanin in their bodies to protect them from the sun’s rays.
- Almost all living organisms share a common ancestry with some organisms. According to Darwin, all living organisms had one common ancestor at one time and have continued to diverge ever since.
- Darwin also said that Galapagos Island birds (Darwin’s finches) evolved different beaks depending on the availability of food. Likewise, he also observed Australian marsupials that showed a number of ancestral marsupials.
- According to Charles Darwin, evolution is a slow and gradual process. He concluded that evolution occurred over a very long period of time. When we talk about the period of time in evolution we usually refer to billions of years. It takes a long period of time to generate one species from another. It is a constant process where changes and Coping take a long time to stabilize and lead to the appearance of new species.
Natural selection takes place in four different ways as follows:
- Variation: Changes accumulated over a period of time in an organism usually give rise to a new species.
- Inheritance: is the transmission of differences across generations, which ultimately leads to the occurrence of a new species.
- High rate of population growth: This causes more organisms to be reproduced by a species than the environment can support.
- Differential survival and reproduction: Superior differences lead to the survival of a given organism, and inferior or negative differences lead to extinction. Superior differences are those inherited during reproduction.
How True is Darwin’s Theory?
Darwin’s classic theory was first published in On the Origin of Species in 1859. After more than a century of technological change and discovery, how precise was Darwin’s theory in describing how life evolved on Earth? Let us share with you some of Darwin’s direct and correct ideas and some of his mistakes.
Correct concepts according to scientists’ belief
How natural selection works within species
Epigenesis is the process of evolutionary change within a group in which one species replaces another without branching off into separate species. Through natural selection, the traits of individuals un suitable for survival within a species diminish, leading to clear changes in size, color, or other traits. While these Copings change a species over many generations, they do not create new branches in its evolutionary path.
The role of natural selection in creating new species
Speciation, the formation of distinguished species during evolution, extends from the ontogeny stage but allows for branching. Isolated populations (organisms of a single species) that reproduce with each other over generations adapt to unique environmental conditions, resulting in differences in traits and behaviors. Over time, these differences may become so pronounced that they hinder successful hybridization between different species, leading to the formation of new species.
Darwin’s evidence to support the theory
Darwin supports his theory of natural selection with evidence from biogeography, paleontology, embryology, and anatomy. He noted that closely related species live in the same areas, which means they have a common origin. Similar species often appear together in the fossil record, reinforcing the concept of evolution. Embryonic development also showed early structures in higher vertebrates. Also, Darwin used anatomy and taxonomy to explain evolutionary relationships between life forms.
Misconceptions according to scientists’ belief
Earth’s age
In Darwin’s time, the Bible was the main source for the age of the Earth, which was estimated at 6,000 years. However, scientists such as Lord Kelvin have suggested that the minimum age should be less than 100 million years due to thermal conduction. Although Darwin’s estimate was more reasonable, modern tools reveal that the Earth is 4.5 billion years old.
Mechanism of variation between individuals
Darwin’s theory of “homogeneity” aims to explain variation among individuals by invoking cytogenetic seeds, which are the seeds of cells provided by parents. This theory was later disproved, as Gregor Mendel’s work in genes revealed that traits are determined by genes, not by cellular seeds.
Conclusion
Although Darwin’s contributions to the theory of evolution were enormous, his ideas developed alongside scientific discoveries and understanding, leading to subtle ideas and mistakes on the journey to reveal life’s secrets.