Macroevolution and Human Evolution: From Hominids to Modern Humans

Introduction

Humans are among the most curious animals on the globe. Over the years, they have formulated biological concepts in an attempt to understand themselves and their surroundings. Their desire to understand their origin has led to the development of evolution theories, and they continue to work on establishing their exact lineage and projecting what may come next. Theologians, philosophers, and psychologists alike have engaged in debate about the origin of humans. While the concept is difficult to explain, it can be understood through the explicit study of evolution.

Macroevolution

The study of humans as biological creatures is referred to as biological anthropology. Macroevolution, distinct from microevolution, examines the specific phenomenon of changes that occurred in species during evolution (Stanford et al., 2009, p. 137). By examining the human hand, we notice very distinct features that can be attributed to phenotypic variations and polygenic inheritance. These variations range from skin color to hair color and texture.

Most human variations can be attributed to environmental diversity. Variation in the quantity of ultraviolet ray exposure brought about variations in skin color (Barsh, 2003, p. 21). Skin color variation is explained by the presence of melanin, which absorbs light into the body. Dark-skinned individuals possess many melanin-containing organelles, while light-skinned individuals possess very few of these organelles (Toda et al., 1972, p. 144). Variation in finger lengths also demonstrates macroevolution concepts; there exists a great difference between the distances of the index and ring fingers in females and males. In females, both the index and ring fingers are approximately the same size, whereas in males, the index finger is smaller than the ring finger (Peters, Mackenzie & Bryden, 2002).

Macroevolution originates from Darwin's theory of evolution. The theory has evolved over the years, and currently, evolution is defined using biological principles. Now, biologists can compare biological similarities to establish the possible lineage of organisms.

Data from fossil analysis indicate that many organisms and traits are lost during the evolution process. These losses are attributed to the concept of "survival of the fittest," where changes in environmental conditions affected many different taxa. The hominids from which humans descended survived geological time by mutating to survive environmental changes. Geological data collected from fossils indicate that hominids existed during different environmental conditions, with different organisms present during different geological periods (Menz, 2005). Organisms that failed to adapt or mutate to survive environmental changes became extinct, such as dinosaurs.

It is also evident that testosterone levels are higher in males from early stages of development. This is perhaps the major reason why there are significant variations in hand sizes between males and females. The hands of modern humans are different from those of early hominids, though resemblances in hand structure are thought to connect humans to hominids. Through successive evolution, humans achieved their present posture (Peters, Mackenzie & Bryden, 2002).

Furthermore, with modern technology, the human hand is affected by activities such as short messaging service writing and typing. When evolution takes its course, the human hand is expected to stiffen in response to its applications. The hand is endangered and might become immobilized or evolve into a weaker limb, having undergone almost all the observable development seen in the world (Menz, 2005).

Creation Theory and Scientific Debate

Creation theory is borrowed from biblical history, where a supernatural being, God, supposedly created humans in their present form. In recent years, analysts have sought to identify the most probable source of human life. Analysis by Philip Johnson indicates that the source of human life must be natural. He argues that evolution theory lacks a base and attempts to relate human life to primitive ancestors that cannot be verified. He concludes that evolution theory is based on theoretical assumptions and should be left as assumption, never taken as fact. In his work, Johnson argues that human life must have been created by an intelligent being, but humans are not simply the results of random events in the past (Menton, 2002).

Critics of creation theory assert that creation exists only through faith, with no evidence or indicators supporting it. Numerous fossils and carbon dating results have verified that life existed on Earth long before the supposed creation event of six thousand years ago. Critics argue that students should be taught realistic sources of human life rather than beliefs. They contend that carbon dating of fossils found across the globe, which show proximate resemblance to humans, indicates that human life has undergone progressive evolution to achieve the upright posture humans possess today (Menz, 2005).

Humans have been social animals since time immemorial. Over four million years ago, the first erect ancestor of humans appeared, developing into what humans are today. Bipedal beings were naturally disadvantaged compared to other animals because they could not outpower, outrun, or outclimb them. The only thing that could help these weak creatures was their ability to form communities, which they used against enemies during hunting and to protect themselves against dangerous animals (Menz, 2005).

Human Evolution

The social aspects of humans—such as love, curiosity, and compassion—developed ages ago, even before humans fully developed intellectually. These instincts were vital during primitive evolutionary times. Most of the social attributes of humans can be attributed to instincts rather than intelligence, as observed in some animals that can be gradually trained to behave in certain ways (Fleagle, 1998, p. 172).

Intelligence quotient (IQ) is the main difference between humans and other animals. The human brain has been developing for over four million years. The combination of larger brains, the ability to communicate, and the capacity to operate in different environments makes humans superior to other intelligent animals (Rantala, 2007, p. 17). Human intelligence has enabled the adoption of social behaviors that further widen the gap between humans and other animals. Through adoption, humans learned that being naked was primitive and worked hard to clothe themselves and develop systems that make them superior to their peers.

Self-discipline and self-control have been instrumental in human modernization. Human sexuality is respected, and human conduct is not based on strength or fighting ability but on more developed systems. Discipline is an important part of human development and, in fact, separates humans from other animals (Hopkins & Leavens, 1998, p. 97).

Various stages of evolution took varying durations. The duration of each hominid stage was recorded after carbon dating of fossils found across the globe. Results were compiled to establish the current understanding of hominid development. However, conflicting ideas have emerged about the order of evolution between Homo erectus and Homo habilis, and between Homo sapiens sapiens and Homo sapiens archaic. The most widely accepted arrangement of these hominids shows progressive development over millions of years (Rantala, 2007, p. 17).

Humans have undergone a series of evolutionary changes from the most primitive hominids to modern humans. The development in hominid structure was gradual, with some creatures being upright and others remaining bent. Evolution is expected to continue, with humans potentially evolving into different creatures depending on the use and disuse of their limbs.

Conclusion

Macroevolution provides detailed information about human origins and substantive evidence from carbon dating, indicating that humans are indeed a product of continuous evolution and not the final product of that process. However, evolution theory has faced considerable criticism, especially from theologians whose views about human origin contradict those of macroevolution. The theory has been rejected by many educational institutions that teach creation doctrine. Nevertheless, evolution remains the most scientifically supported theory regarding human origin.