Landmarks in the History of Evolutionary Thinking

When discussing history, we often refer to a timeline of events that culminated in changes, clarifications or understandings. When talking about human beings or other life forms, a sequence of events led to contemporary times. Jean Baptiste Pierre Antoine de Monet Chevalier de Lamarck was the earliest expert to employ the term "biologie," acknowledging the science of life as a separate discipline. He held that two main factors lead to taxonomic transformation: a species' innate propensity to evolve into a higher dimension and, second, the passing down of acquired traits.

Landmarks in the History of Evolutionary Thinking

Baron Georges Léopold Chrétien Frédérick Dagobert Cuvier created a different hypothesis of how biological forms originate. Per the catastrophism idea he postulated, species are routinely wiped out by unexpected disasters like comets and replaced by new ones. Other scientists had also noted the astounding range of organisms, some of which shared a startling resemblance. For instance, each pair of hands and feet have precisely five fingers on humans, chimps, and orangutans.

The similarities between bird wings and seal waders could mean one has been amended by the other. In contrast to what some researchers and theologians had said, parallels between different species revealed that creation was not stagnant.

Before Darwin, other evolutionists had noted another crucial fact: Many animals have traits that appear to serve a purpose. The quills of the porcupine aid it in warding off predators. The turtle's carapace assists in defending its delicate organs from the corrosive effects of nature. The abundance of this apparent usefulness in nature necessitated an interpretation.

However, a theory that clarifies how modification may occur through time and how intentional architecture could have come about was absent from the evolutionists' explanations before Darwin. Charles Darwin established the causality or procedure necessary to describe these biological occurrences.

The Era of Charles Darwin

Darwin has studied two theirs as theory of natural selection and theory of sexual selection.

Theory of Natural Selection

Darwin wanted to clarify not just why change happens over time in living things but also speak for the specific ways it happens. He was interested in how life forms appear and how others disappear. Darwin sought to elucidate various issues, including animal components in those specific forms.

These problems' solutions can be linked to a trip he took across the globe on a ship and brought back from the Galápagos islands in the Pacific scores of specimens of birds and other species. Upon his return, he learned that the Galápagos finch, which he had previously assumed to be all members of a single taxon, apparently differed to the point of being distinct species.

He discovered that while having a similar ancestor, these various finches separated from one another due to the unique biological circumstances of each territory. His finding that animals are not eternal but can evolve critically depended on this spatial variation. Darwin sought to explain the change and why species seemed well-suited to their immediate environments.

Formally speaking, Darwin's solution to all of these biological conundrums was the idea of natural selection, which has three key components: variability, heredity, and choice. Organisms differ in various ways, including wing extent, trunk power, bone density, cytoskeleton, combat and lateral agility, and social cleverness. Variety is the "raw resource" for evolution, which is necessary to proceed. Second, just sure of these variants are acquired.

Some changes brought on by a natural disaster are not passed down to kids. The only variants that contribute to creation are the ones that are transmitted. Selection is the third essential component of Darwin's theory. Because these traits aid in survivability or procreation, creatures with some genetic variations generate additional offspring. An organism may endure a lifetime without passing on its hereditary traits to its descendants. It must breed to pass on its hereditary traits to subsequent generations.

Theory of Sexual Selection

Darwin had an excellent scientific tendency to observe data that contradicted his beliefs. He noticed several things that appeared to go against his notion of natural selection. He began by observing strange structures that appeared to be unrelated to surviving, such as the dazzling peacocks' plumes. Darwin also noted some species' significant size and structural differences between the genders.

He devised a second evolutionary science, the idea of sexual selection, to respond to these apparent setbacks. The doctrine emphasized modifications that emerged as a result of practical breeding. Darwin proposed two main ways that sexual selection might work. The initial is intrasexual rivalry, which occurs between individuals of the same sex and results in accessibility to the other sex during mating.

Two stags engaged in conflict is the archetype of intrasexual struggle. The winner has entree to a female, perhaps straightforwardly or by dominating the area or assets that the female desires. By way of the winners' accomplishment in mating, whatever traits contribute to victory in same-sex competitions, such as increased size, power, or athletic skill, will be handed to the following generation.

Therefore, intrasexual rivalry can result in evolution—change through time—by itself. Intersexual selection, often known as selective mate choice, is the second-way sexual selection might be at work. People of the opposite gender will be given preference when choosing partners if individuals of one sex agree on the attributes they seek in partners of the other sex. Individuals who do not possess the desired traits do not find partners.

The Contemporary Synthesis: Particulate Transmission and Genetics

Mendel's research demonstrated that heredity was "particulate" rather than integrated. In other words, the traits of the guardians are not mixed together but are instead transmitted to their progeny in separate packets known as genes. Additionally, genes cannot be gained by experiences; instead, they must be present at birth in the parents.

For around 30 years, most scientists were unaware of Mendel's findings, which he showed by breeding various pea plants. Mendel had copied his papers and sent them to Darwin, but either they were never read, or their importance was not understood. The "Modern Synthesis" paradigm of the 1930s and 1940s resulted from integrating Darwin's evolutionary theory based on natural selection with the finding of granular gene heredity.

The Modern Synthesis disproved many biological myths, notably Lamarck's notion of acquired character transmission and the mixing concept of inheritance. A clear grasp of the nature of heredity strengthened Darwin's natural selection theory and reaffirmed its significance.

Other Important Milestones

These are −

The Ethology Movement

The area of ethology was the first essential facet to emerge around the behaviourist approach from an evolutionary standpoint, and imprinting was among the initial occurrences they recorded. Ducklings attach during a crucial developmental stage when they stamp the initial movement item they see. This item is typically the mother duck.

Imprinting is unmistakably a type of learning since it creates a connection between the duck and the parent that did not exist before it was exposed to her movement. Nonetheless, this learning process is "preconfigured" and a component of the biologically evolved architecture of the duckling. "The investigation of the immediate mechanics and functional significance of animal behaviour" is the definition of ethology. To define what they thought to be the inherent qualities of animals, ethologists created various categories. The aetiology movement significantly influenced biologists' perspectives on the value of adaptability.

The Transformation in Inclusive Fitness

Hamilton put out "inclusive fitness theory," a bold new reworking of evolutionary theory. He believed that the term "traditional viability" was too limited to adequately characterise the evolution process via selection. This term refers to an individual's actual reproductive potential in transmitting genes through the generation of offspring. He postulated that irrespective of whether an organism produces kids, natural selection favours traits that cause its genes to be passed on.

By assisting siblings, cousins, or other family members in surviving and procreating, an organism can also promote the replication of its genes. There is a chance that each of these relatives carries a few of the organism's genes. Hamilton's insight that the notion of classical fitness should be widened to include all types of fitness was what made him so brilliant. A new era known as "gene's eye vision" may have been ushered in by the inclusive fitness revolution.

The essential idea is that the gene, which is passed on the whole during reproduction, is the basic unit of heredity. Throughout time, other genes will be replaced by those that produce effects that boost their ability to reproduce, leading to evolution. The inclusive fitness argument has significant ramifications for how we perceive violence, social dynamics, altruism, and family psychology, among other concepts.


Some people find it easiest to visualise evolution when it pertains to tangible buildings. The adaptations of a turtle's shell for defence and a bird's feathers for flight are both clear to see. Most folks consider it rather simple to assume that humans and chimpanzees share a shared ancestry since we see parallels between ourselves and chimpanzees.

But it is critical for comprehending the sequence of events that led to the concepts we use today to gain insight into both other animals and ourselves.

Updated on: 11-Apr-2023


Kickstart Your Career

Get certified by completing the course

Get Started