The descent of humans and the Darwinian unification of all life

Abstract

The biological revolution that Darwin initiated has given us a view of an earth that was once devoid of life and where life originated and evolved from simpler pre-existing forms over immense periods of time. Darwin saw human beings as an integral part of this evolutionary history. How, when and where life originated remains an inscrutable challenge to science. However, discoveries in every branch of biology since the time of Darwin have affirmed the essential unity of life, including the 30 million or more extant species and more than 600 million extinct species. Darwin’s graphic representation of relationships between organisms is now employed to construct phylogenetic trees at all levels of biological organization. A Neanderthal fossil was the only hominin remain known at the time of Darwin. Today paleoanthropologists work with more than 20 species of hominins. The study of these fossil ancestors combined with the molecular dating techniques based on the analysis of mutations in mitochondrial and Y-chromosomal DNA have vindicated Darwin’s worldview of the origin of humans in Africa, as well as his suggestion that the great apes are the closest living ancestors of Homo sapiens. The discovery that all human beings on earth are descendants of one woman, the African ‘Eve’ who lived not more than 200,000 years ago has extended the Darwinian biological worldview into a unifying philosophical perspective. It is now possible to determine the mitochondrial and Y-chromosomal branch (haplogroup) of any human being with comparative ease. This helps in tracing the possible time and route of migration of our ancestors. The emerging consensus that our ancestors left Africa as recently as 70,000 years ago has profound implications for history, culture, linguistics, psychology and human predicament. The unification of all life, including human life is perhaps the most enduring contribution of Darwin’s evolutionary theory. Human beings are yet to fully comprehend the significance of this unification. Perhaps there is a lesson in Darwinism for how we humans should deal with each other and treat other life and nature with which we have an organic and primeval connection.