From Whence Do We Come? Part 2 (of 2)

From Whence Do We Come? Part 2 (of 2)

Recent Fossil Find and Human Evolution

 Many people regard the hominid fossil record as compelling evidence for human evolution. These remarkable creatures presumably represent evolutionary intermediates between an ape-like creature and modern humans.

Most evolutionary models for human origins place Homo erectus as part of the lineage that leads to modern humans. H. erectus is often viewed as intermediate in morphology and behavior between the great apes and modern humans.

The recent analysis of an H. erectus skull recovered near Lake Turkana, Kenya, in 2000 suggests a different relationship between H. erectus and modern humans.

To the surprise of paleoanthropologists, this fossil is far smaller than expected for an H. erectus specimen. With this find, the size variability for H. erectus widens to that observed for the great apes.

Large size disparity in primates is diagnostic for sexual dimorphism. (Sexual dimorphism refers to a systematic size difference between males and females within a given species.) The great apes (and the australopithecines that preceded H. erectus in the fossil record) display sexual dimorphism. In contrast, males and females in modern humans are relatively close in size.

The size inequality of males and females in primates gives anthropologists important insight into the behavior and lifestyle of H. erectus. Primates that exhibit sexual dimorphism have a social structure that centers around a dominant male that reproduces with a harem of females. On the other hand, primates that are characterized by limited sexual dimorphism form monogamous pairs.

Anthropologists have long thought that H. erectus was progressively becoming human-like in its behavior. This new find, however, means that the behavior and lifestyle of H. erectus was ape-like. This recognition confirms the results of earlier studies which indicate that the growth and maturation of H. erectus was ape-like, not intermediate between apes and humans.

The sexual dimorphism of H. erectus increases the separation between this hominid and modern humans, diminishing its status as a transitional form. However, the ape-like behavior of H. erectus comports well with the RTB explanation for the hominids.

RTB’s biblical creation model views the hominids found in the fossil record as animals created by God’s direct intervention. These creatures existed for a time and then went extinct. RTB’s model considers the hominids to be remarkable creatures that walked erect and possessed some level of limited intelligence and emotional capacity. This ability allowed these animals to employ crude tools and even adopt some level of “culture” much like baboons, gorillas, and chimpanzees. While the RTB creation model posits that the hominids were created by God’s divine fiat, they were not spiritual beings made in His image. The RTB model reserves this status exclusively for modern humans.

The model treats the hominids as analogous to, but distinct from, the great apes. Because of this, the RTB model predicts that anatomical, physiological, biochemical, and genetic similarities will exist among the hominids and modern humans to varying degrees. But since the hominids were not made in God’s image, they are expected to be clearly distinct from modern humans, particularly in their cognitive capacity, behavior, “technology,” and “culture.”

RTB’s creation model makes sense of the latest insight into the lifestyle of H. erectus. On the other hand, the close alignment of H. erectus with the great apes and the widening separation between this hominid and modern humans leaves an uncomfortable gap to explain for human evolutionary models.

For more information on the relationship between H. erectus and modern humans see Who Was Adam?

Part 1 | Part 2