WEEK 12 - SAMPLE LAB EXAM QUESTION
- QUESTION:
The figure compares the growth of skulls of chimpanzees and humans. Both adult skulls are plotted on transformed co-ordinates, showing the relative displacement of each part during development. The chimpanzee and human skulls are very similar as fetuses. The human skull undergoes little alteration during development, while the adult chimpanzee skull departs considerably from the fetal form. Human ancestors showed skull development similar to that shown for the chimpanzee.
- Name the type of modification of timing of developmental events described for human evolution.
- How is neoteny important in vertebrate evolution?
- ANSWER:
- Heterochrony or, more specifically, neoteny.
- In chordate evolution, ancestral tunicate-like form lost adult sessile stage and produced a sexually mature free-swimming 'larva'. This neotenous line lead to vertebrates.
(See Demonstration 4, Week 3)
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