Bipedalism Is One of the Most Important Characteristics of Hominin

question 43

Multiple Choice

Bipedalism is one of the most important characteristics of hominin evolution. The appearance of bipedalism led to anatomical changes that are considered to be distinguishing characteristics of hominin fossils. The evidence for bipedalism is supported by fossil evidence from more than 4 million years ago and 3.6-million-year-old footprints in volcanic ash.
Recently, however, scientists have focused on the link between tooth structure and diet in the evolution of the early hominins, specifically in Australopithecus species. Detailed studies of hominin dental features have provided evidence of an important dietary shift that led to adaptive radiation within this genus. Most of the evidence comes from analyses of tooth size and shape, microscopic wear patterns on teeth, and jaw structure. The evidence suggests that fibrous plant materials became more important through the Pliocene, perhaps as critical components in the diet of some species.
-Evidence from fossil dentition suggests that Australopithecus species

• A) evolved specifically to eat meat.
• B) experienced a decrease in both tooth size and brain size.
• C) were direct ancestors of modern humans.
• D) were adapted to function successfully in a wide range of habitats.

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Definitions:

Spontaneous Recovery

The reappearance of a previously extinguished response after a period of non-exposure to the conditioned stimulus.

Classical Conditioning

A learning process that occurs through associations between an environmental stimulus and a naturally occurring stimulus, famously demonstrated by Ivan Pavlov.

Conditioned Response

A learned reaction to a formerly neutral stimulus that has become conditioned after being paired with an unconditioned stimulus that naturally produces a response.

Time Delay

Time Delay refers to the period between an action being initiated and its outcome or effect being observed.