Human Evolution: From Biology to Anthropology

Posted on Dec 14, 2024 in Philosophy and ethics

The Biological Nature of Man: Nature and Origin

19th Century Responses: Religious and Scientific

In the 19th century, responses to the question of human nature were primarily religious and scientific. Science eventually took over as the primary means of answering these questions. The scientific search for answers does not mean giving up the search for meaning in human nature.

1.2 Anthropology: Understanding Human Biological and Social Aspects

Anthropology is the science dealing with the biological aspects of humans and their behavior as members of society.

  • Biological Anthropology: Studies anatomical and physical changes that humans have undergone throughout their biological evolution.
  • Hominization: The physical process of becoming “Homo sapiens.”
  • Humanization: The cultural process of becoming human.
  • Sociocultural Anthropology: The study of humans as organic beings in relation to others. It involves comparative study between different social systems and forms of group behavior.
  • Philosophical Anthropology: Aims to understand human beings, recognizing and acknowledging their peers as people in terms of values, rights, equality, and freedom.

The study of the human biological dimension requires two aspects:

  • Evolution: A fact that affects the entire universe, not only living beings. We need to understand, at least, the development of the theory of evolution.
  • Morphological Changes: Changes in evolution that have been generated in different species until the appearance of human beings. This process is called hominization.

2. Theory of Evolution

2.1 Traditional Thinking: Creationism, Fixism, and Spontaneous Generation

The following theories were firmly established in society:

  1. Creationism: Living things were created by God. Genesis: Descent of Man (Bible). Aristocratic vision. Muslim influence.
  2. Fixism: Proposed by Linnaeus. Species do not evolve; they remain unchanged. Based on Aristotle. United science and religion (creationist fixism).
  3. Theory of Spontaneous Generation: Organisms originated from substrates.

2.2 Scientific Revolution and Development of the Theory of Evolution: Lamarck, Darwin, and Mendel

16th, 17th, and 18th Centuries: Physical reductionism was propelled by Copernicus, Galileo, Kepler, and Newton. The new appearance of science facilitated the investigation of the laws governing the universe. Society accepted the heliocentric theory, abandoning geocentrism in the 19th century.

Lamarck, Darwin, and Mendel: The biological revolution prompted:

  1. Biology became the science that contributed most to the change in mentality of our society.
  2. Lamarck developed the first scientific theory of evolution, which was the reason for violent controversies.

Since the late 19th century, the concept of evolution has acquired a much broader meaning. Today, it means that not only do organisms gradually evolve, but also the universe (cosmic evolution).

Lamarck’s Theory

Lamarck formulated his theory according to two principles:

  1. The Law of Use or Disuse of Organs: Organs develop or atrophy according to their use or lack of use.
  2. The Law of Inheritance of Acquired Characteristics: These changes are transmitted to offspring, which would explain why some species are transformed into others.

Darwin’s Theory of Natural Selection

  1. Living things tend to multiply in proportion to the food possibilities offered by the environment.
  2. Individuals of the same species have different traits or characteristics.
  3. Characteristics favorable to the demands of the environment are more likely to reproduce and survive than those with less favorable characteristics.
  4. Favorable characteristics become more frequent, and unfavorable ones become less frequent.

Result: Different species arise because of these attributes in individuals. Darwin’s ideas were applied to the economy, and he took ideas from it.

Mendel’s Laws of Inheritance

  • The Law of Uniformity: If two pure strains of plants that differ in one feature (e.g., flower color) are crossed, all their descendants will be hybrids. The color of one parent will manifest (e.g., purple), while the color of the other parent will remain latent (e.g., white).
  • The Law of Segregation: If these hybrids are crossed with each other, 25% will be white (pure) and 75% will be purple. Of these purple offspring, only 25% will be pure purple, while the remaining 50% will have a purple appearance but will be hybrids, carrying the white gene in a dormant state.
  • The Law of Independent Assortment: If two pure varieties of plants that differ in more than one characteristic are crossed, their genes are transmitted independently, so that the resulting characteristics are distributed in the proportions set out in the first law.