Theories of Evolution and the Origin of Man
Theories of Evolution
Fixism vs. Evolutionism
Humans have always been curious about their origins. Understanding our past helps us understand our present and future. One theory is fixism, proposed by Georges Cuvier, which posits that all species are independent and unchanging since their creation. In contrast, evolutionism, gaining prominence in the 19th century, proposes that the universe and life are products of gradual development. Evolutionism had precursors in 18th-century transformism, championed by Leclerc and Maupertuis, which suggested that new species arise from the transformation of existing ones.
Lamarckism
Lamarckism, detailed in Zoological Philosophy by Jean-Baptiste Lamarck, is considered the first comprehensive theory of biological evolution. It proposes:
- A gradual progression from simpler to more complex organisms.
- Adaptation to the environment through the use and disuse of organs drives change. Used organs develop, and disused organs atrophy.
- Acquired characteristics are inherited, leading to better adaptation.
While Lamarck lacked evidence for the inheritance of acquired traits, his work significantly contributed to evolutionary thought.
Darwinism
Following their observations during a voyage to the Galapagos Islands and South America, Charles Darwin and Alfred Russel Wallace presented a new theory of evolution based on natural selection. The struggle for survival due to limited resources leads to the survival and reproduction of the fittest individuals, who pass on their advantageous traits. Darwin’s theory, while superseding Lamarckism, lacked a complete explanation of heredity, which was later provided by Gregor Mendel’s work on genetics.
Mutationism
Following Mendel’s discoveries, mutationism emerged, proposing that evolutionary progress depends on mutations. Hugo de Vries distinguished between non-heritable variations caused by environmental changes and heritable mutations occurring in genes. However, the causes of mutations remained unclear.
Neo-Darwinism (Synthetic Theory)
The debate between natural selection and mutationism led to the synthetic theory of evolution, integrating Darwinian natural selection with Mendelian genetics. This theory incorporates data from zoology, paleontology, botany, and molecular biology to explain the evolutionary process. While the exact mechanisms are still debated, this theory posits that mutations create heritable variations, and natural selection guides evolution by favoring advantageous traits.
The Origin of Man
Thomas Huxley, Charles Darwin and Ernst Haeckel defended in the second mitas nineteenth century that human beings should be evolutionarily anthropoid animal species. Most humans are similar to those classified in the family and hommínidos pongids póngidos.Los belong to the superfamily of hominoids or arthropods, and the only hominids living species is the human being: Homo sapiens.
Although not determined which due the last ancestor of Homo, if you have found abundant Possibly, processes that allow the reconstruction of the evolutionary process to reach the present form of human being.
Australopithecine, lived in the jungle had a cranial capacity of about 500cm 3 and were bipedal. In the same time it was Homo habilis front is characterized by a wider, increased cranial capacity hastra about 700cm 3 and a change in living arrangements.
Homo Erectus, Homo habilis over Homo erectus, whose fossil is between one and half million to 300,000 years, were bipedal and walked upright, had between 900 and 1200cm 3 of cranial capacity, used fire, and practiced rituals associated built burial and stone tools. Homo erectus is believed that one hand evolved Homo neanderthalensis and Homo sapiens on the other. However, the latest findings appear to confirm the existence of other branches and missing links.
Homo sapiens, appeared about 100,000 years ago Áfricay Middle East 40,000 years ago in Europe. Was nomadic and lived by hunting but also began to practice agriculture and animal husbandry. Fabrice weapons and tools. used clothes stitched and adorned, and was buried the dead with reverence and drawing various works of art. He had a cranial capacity of men or greater.
In a new process that anthropologists call humanization. man gradually becomes independent of the natural pressure of the medium because it fits not only biologically but also through the cultural world he creates and makes him who he is.