An Introduction to Anthropology and Human Evolution
Anthropology
Anthropology is the science that deals with the biological aspects of humans and their behavior as members of a society. Its area of activity covers three dimensions: the biological dimension, the cultural dimension, and the philosophical dimension of the human being:
Biological Anthropology
Biological anthropology studies the anatomical and physical transformations experienced by humans throughout their biological evolution, as well as their origin and differentiation as a species in the animal world. Biological anthropology is focused on reconstructing the process of humanization to find out the origin of humans from other animal species.
Sociocultural Anthropology
Sociocultural anthropology studies human beings from their relationships with other living beings. Its research deals with the comparative study between different social systems and different types of group behavior. It also investigates the techniques and resources that humans have developed to adapt natural and social media to their needs and the way to preserve and transmit these techniques and resources throughout history.
Philosophical Anthropology
Philosophical anthropology tries to establish, in line with science, the place of human beings in the world, their origin and nature, but focusing on understanding the human being as a person in terms of values, rights, freedoms, and equality.
Theories of Human Origin
Non-Evolutionist Theories
Before the nineteenth century, three theories shaped the knowledge about the origin of all living things in the European mentality. These theories rejected any idea opposed to the assertions of Aristotle or the Bible.
Creationism
This theory asserts that the world and all living things were created by God from nothingness. It is the basis of many religious doctrines, not only of Christianity. In Judeo-Christian culture, it is presented in the Bible. Based on a literal interpretation of the book of Genesis where it is said that:
- All living species were created separately by God from nothingness at the beginning of time.
- God created mankind in his own image. So the human being plays a special role in the divine creation.
Fixism
Carl Linnaeus stated that species, both plant and animal, do not evolve but remain unchanged over time. In fact, until the nineteenth century, it was widely believed that God had created all species, plants and animals, at the beginning of the world as they are now. To explain the fact, as evidenced by the fossils, of the disappearance of certain species and the emergence of new ones, fixism was complemented with the catastrophist explanation. According to this theory, some species disappeared as a result of some natural disasters such as the Great Flood.
The Theory of Spontaneous Generation
This theory asserts that some microorganisms appear from inert substrates by spontaneous generation. The origin of this theory is in the Aristotelian claim that certain inferior living beings are generated spontaneously from mud and decaying organic matter.
Lamarck and the Inheritance of Acquired Characteristics
Although Lamarck recognized divine participation and spontaneous generation in the emergence of species, he established a hierarchy among species. The novelty of Lamarck’s theory was a successive transformation of the characteristics of the species to adapt to the environment. These transformations led to the emergence and evolution of new species up to now.
His theory is based on two principles:
- The Law of the Use or Disuse of the Organs. In every animal that has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens it, while the permanent disuse of any organ imperceptibly weakens and deteriorates it and progressively diminishes its functional capacity until it finally disappears. Thus, this first law relied on the belief that “exercise develops an organ.”
- The Law of the Inheritance of Acquired Characteristics. The characteristics acquired by the predominant use or permanent disuse of any organ are preserved by reproduction to the new individuals that arise.
Darwin and the Theory of Natural Selection
The principal merit of Darwin’s theory is the discovery of the mechanism that governs the entire evolutionary process of species: natural selection. Darwin’s natural selection theory can be summarized in the following steps:
- Firstly, life is characterized by the capacity for reproduction, so living beings tend to multiply because of food possibilities. But when environmental resources become scarce, competition occurs and, consequently, the struggle for survival begins.
- Secondly, individuals of the same species have different characteristics that appear randomly.
- Third, those whose characteristics are favorable to the demands of the environment are more likely to reproduce. Only the fittest individuals survive. The concept of the “fittest” does not mean to be stronger, more intelligent, or of a superior culture.
- Finally, the favorable characteristics are increasingly widespread, while unfavorable ones are becoming rare until they finally disappear. The result will be a new, different species.
Mendel and the Laws of Genetic Inheritance
Mendel is considered the father of genetics because of his research on the mechanisms of heredity. His work was to observe the crossing of thousands of peas with distinct characteristics of color and texture, demonstrating that the common opinion that affirmed that characteristics were transmitted from parents to offspring mixed was false. Heredity occurs in three laws:
- Law of Segregation. During gamete formation, the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene.
- Law of Independent Assortment. Genes for different traits can segregate independently during the formation of gametes.
- Law of Dominance. Some alleles are dominant while others are recessive.
The Modern Evolutionary Synthesis
provides an explanation of evolution, accepted as the current paradigm in evolutionary biology, and how evolution works. This synthesis tries to explain how the Mendelian genetics can be reconciled with gradual evolution by means of Darwinian natural selection. Genetic variability is caused by mutations and genetic recombination. Natural selection works by choosing those characteristics that are useful to adapt those organisms to the environment.
a) Social Darwinism extrapolation of the concepts used in the theory of Darwinian evolution from Biology to other aspects of the human reality as economy, society or politics, establishing the false idea that nature legitimises. Only the fittest will adapt to the market and to society, while other individuals would be gradually eliminated. Social Darwinism represented one of the ideological pillars of the colonialist expansion carried out by European nations during the second half of the nineteenth century and early twentieth century. The pseudoscientific assertion about the existence of a race which is called to dominate and subdue the other races spread between the common ideology of that time.
culture as the set of knowledge, beliefs, customs and human inventions. The notion of culture includes:
• The tools, and techniques and technological works that human being has invented. From the primitive tools to hunt and grow to the most sophisticated computers
• Knowledge, beliefs and opinions which are products of human creativity. Language, literary and artistic works, religious beliefs or myths are some clear examples of this creativity.
• Social customs, different ways of greeting, dance, play, and punishments.