The First Bipeds Key Terms

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Chapter 6

• The First BipedsKey Terms

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• AustralopithecusThe first well-known hominine
  lived between 4.2 and 1 m.y.a. Characterized by
  bipedal locomotion when on the ground, but with
  an apelike brain includes at least five species
  afarensis, africanus, anamensis, boisei, and
  robustus.

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• savannahArid plains environment of eastern
  Africa.
• Ardipithecus ramidusOne of the earliest hominins
  that lived in eastern Africa about 5.8 to 4.4
  million years ago.

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• diastema A space between the canines and other
  teeth allowing large projecting canines space
  within the jaw.
• Kenyanthropus platyopsA new proposed hominin
  contemporary with early australopithecines may
  not be separate genus.

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• gracile australopithecinesMembers of the genus
  Australopithecus possessing a more lightly built
  chewing apparatus.
• robust australopithecinesSlightly larger and
  more robust than gracile members of genus
  Australopithecus, with larger, more powerful jaws
  and teeth.

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• sagittal crestA crest running from front to back
  on the top of the skull in the midline to provide
  a surface of bone 0for the attachment of the
  large chewing muscles. 
• law of competitive exclusionWhen two closely
  related species compete for the same niche, one
  will out-compete the other, bringing about the
  latters extinction.