Question

Answer all the questions please

Station 4: Tooth Proportions (Measure the Specimens from Stations 2 and 3) 1 The relative size of the anterior and posterior dentition has changed through time and is dependent upon dietary adaptations. Tooth proportions can be measured to track that change. Measure the width (side to side) of a central upper incisor and of an upper second molar (lingual side to buccal side). Then calculate an index to obtain a ratio of incisor-to-molar width Incisor width x 100 Molar width Incisor width M2 width Index Chimpanzee 3 5mm A, afarensis 3 mm 4mm (93 A. africanus 8 Robust australopith Modern human 4 Many of the fossil casts lack teeth, or are missing the teeth you were asked to measure. Just put "missing" in the box if this is the case. However, if you look at photos of the specimens in the book or review the information on the section for the species earlier in this chapter, you may get an idea about size of incisors and molars. In that case, you can put a descriptive term instead of a measurement. You could even measure the teeth in photos if necessary 2 What did this tell you about tooth proportions-the relative size of incisors and molars? Do any of these specimens group together with similar measurements (or similar descriptions)? 3 Given that the ape is presumably the most similar to the common ancestral condition, and A. afarensis is the oldest australopith, and humans obviously the most recent, can you say anything about trends in tooth proportion over time? 376 Exploring Physical Anthropology

Answer 1

2.

This tells us that A africanus had a large incisor width and which subsequently decreased after that.where as the molar width is greater for robust australopithecus and change in the molar width is seen in each group.

Yes the A. Afranensis and A. Africanus have similarly because of the index ratio is somewhat similar, and robust australopithecus and chimpanzee have the same incisor measurements.

3.

As the modern human have involved here shows the decrease in the tooth proportion as we can see the index decreases when we come down the table. Incisor width first increases and then decrease whereas the molar size increases until reches the modern humans where it is decreased.

Thank you.....