Human Evolution: From Creationism to Bipedalism

Basic Thesis of Creationist Theory

The basic thesis of the creationist theory is the creation of separate and final species and the creation of man by God in His image and likeness.

Fixist Course

It defends the unchanging character of all species over time.

Linnaeus and Cuvier

They considered that the adaptability of individuals to the environment is the result or product of intelligent design.

Lamarck's Theory

The environment changes, causing changes in the life systems and needs of living organisms. Changing needs cause changes in behavior to meet new needs. This leads to changes in the anatomical structure and/or physiology of living organisms. The acquired characteristics are inherited by descendants.

Paleontology

Paleontology is the science that studies extinct plant and animal species whose remains are found as fossils.

Mendel's Theory

Mendel's theory of inheritance assured that hereditary traits are determined by specific factors.

Mutations

Mutations explain changes in the characteristics of species from alterations or mutations in the genetic material.

Neo-Darwinian or Synthetic Theory

Neo-Darwinian or Synthetic Theory combines the theory of natural selection and mutations as its basic doctrines.

Theories on the Origin of Modern Humans

Multiregional Hypothesis (Candelabra Theory)

The Multiregional Hypothesis states that the origin of modern humans is multiregional, meaning that different evolutionary processes occurred in different places of the prehistoric world. There was a genetic exchange among the many existing populations. Therefore, the origin of humans could have occurred in any of these genetic enclaves. Each exchange would have contributed to creating the human species as we know it now.

Out of Africa Theory (Noah's Ark Theory)

The Out of Africa Theory states that current humans have a unique origin located in Africa. Modern humans migrated exclusively from Africa and gradually occupied other parts of the world, completely replacing the oldest populations that had lived there until then.

Bipedalism

What is Bipedal Gait?

Bipedal gait is walking on two feet without using hands for support. It provoked a series of changes in the curvature of the spine, strengthening of the neck, and, above all, it permitted observation of larger natural areas and the release of the upper limbs while walking.

What Allowed Upright Walking?

Upright walking allowed hands to specialize in functions distinct from locomotion: the manipulation of objects, hunting, defense, and construction. It also allowed the utilization and invention of all kinds of tools.

Hand Release

The greater the expertise in handling and manufacturing objects, the greater the ability to ideate and conceive them. Conversely, a higher cerebral capacity leads to greater dexterity.

Technical Capacity

Technical capacity is the ability to manufacture and use tools to change the environment and thus meet our needs.

Symbolic Capacity

Symbolic capacity is the ability humans have to create and express themselves through symbols.

What are Symbols?

Symbols are the ability humans have to create and express themselves through symbols. They are conventional, meaning they bear no causal or resemblance to the reality they represent, but the connection has been established by people.

Professor André Leroi-Gourhan's Proposal

Professor André Leroi-Gourhan proposed that the emerging use of instruments forced hominids to free their hands and take an upright stance. This would have enabled them to expand their cranium and, with it, the size and complexity of the brain.

Why do Many Thinkers Believe Language is a Human-Specific Trait?

Although animals can emit and understand basic emotions through signs, they cannot express more complex realities, like instructions, theories, rules, or values. Humans, however, can do so through language. For many thinkers, language is a qualitative difference, a human-specific trait.

Hypotheses Underlying Language Theory

It is assumed that articulate language has been derived from a first sign language. How, when, and why did gestures lead to articulated communication? There are various scenarios:

• A genetic mutation
• The gradual increase of general intelligence
• The generalization of hand signals

It is possible that the three previous theories are complementary.