Question

1) In general, is the dentition of Australopithecus afarensis more human-like, ape-like or in-between? List two examples (traits) to support your answer. Be specific about the condition of this trait. Make sure the you will provide a reasonable explanation and examples.

2 )List three special morphological (physical) adaptations of the robust Paranthropus associated with heavy chewing.

.In general, is the dentition of Australopithecus afarensis more human-like, ape-like or in-between? List two examples (traits) to support your answer. Be specific about the condition of this trait.

Answer 1

Answer 1: Austalopithecus afarensis is the best known human ancestors found around 3.9 to 2.9 billion years ago. Fossil studies showed that this species had many ape-like and human-like features.

One such key physical feature is their jaw and teeth arrangements which was found to be in-between human and apes.

• The most prominent evidence was canine teeth which was found much longer and pointed than other teeth, and its size was intermediate between humans and apes.
• The diastema (gap between teeth) were found between canine and the neighbouring teeth, which is an ape like feature who have these gaps between canine and incissor in upper jaw whereas between canine and premolar in lower jaw.
• The front premolar teeth were found to have one large cusps like apes.
• Whereas the back molar teeth have five cusps on their chewing surface of the teeth (also called ‘Y-5’ pattern just like humans.
• Also the front incissors were found to be wide and large.
• the teeth in the lower jaw are arranged wide apart at back than in front, whereas in the upper jaw the arrangement of the last molar causes a curve at the back.

Answer 2:

• Paranthropus robustus had very large megadont teeth with thick layer of enamel that helped in chewing at the back of the jaw.
• The large chhek bones also called zygomatic arch causes the progression of chewing muscles to the jaws taht helped in chewing and gave this species disc-spaed face.
• the sagittal crest (a ridge of bone on the top of the skull) that helps connect the chewing muscles of the jaw to the skull. The prescence of well-built sagittal crest indicates strong chewing jaw muscles.