Evolutionary Theories and the Rise of Homo Sapiens

From Fixism to Biological Evolution

Fixism was proposed by Georges Cuvier. This theory considers all species to be independent and remain unchanged throughout time since their creation.

Lamarckism: The First Evolutionary Theory

Lamarckism is the first theory of biological evolution, developed by Jean-Baptiste Lamarck. This theory defends the following claims:

• There is a transformation of bodies from simple to more complex forms.
• The exercise of an organ produces development and perfection.
• Acquired characters are inherited to ensure better adaptation.

Darwinism and Natural Selection

In London, Charles Darwin presented a new theory of evolution based on these principles:

• Evolution is a struggle for survival because there are more living beings than available resources.
• This leads to a process of Natural Selection.
• Darwin lacked an adequate theory to explain how variations are inherited.

Mutationism and Genetic Change

The theory of Mutationism states that evolutionary progress depends on mutations. Mutations are changes occurring in the genes of living organisms that are subsequently inherited.

The Synthetic or Neo-Darwinian Theory

This theory attempts to integrate the Darwinist principle of natural selection with the principles of genetics and mutations. According to this theory:

• Random mutations in organisms are inherited.
• Natural selection ensures that the best-adapted individuals survive.

The Origin and Development of Man

The human species, Homo sapiens, developed from anthropoid ancestors. They appeared in Africa approximately 100,000 years ago and in Europe 40,000 years ago. Early humans were nomadic hunters who eventually began practicing agriculture and livestock farming, manufacturing tools such as knives, axes, and stone implements.

The Process of Humanization

Humanization is the process by which man becomes independent of the surrounding natural environment. Humans adapt not only biologically but also through a world of culture that they create, which defines their unique nature.

Differences from Animal Ancestors

While there are no large biochemical or genetic differences between humans and anthropoids, significant anatomical differences exist:

• The size of the teeth and mandible.
• The size and dexterity of the hands.
• Bipedalism and upright posture.
• Advanced brain development.

Behavioral Distinctions

• The capacity for symbolization: Communication through symbols.
• Opening to the world: Humans are able to understand things beyond immediate space and time; they are not locked in their environment but open to the world.
• Free will: Humans are the only animals able to say "no" and choose their own future.
• Incompleteness: The human being is never finished and always feels a desire for more.
• The ability to think and reason: Imagination allows us to create projects and ideals, while reason is the ability to ordain those projects.