Questions for Further Thought

1. In our discussion of Psilophyton and Pertica, we note that this evolutionary transformation led to an increase in reproductive output both because of overall increase in plant size and because Pertica produced more sporangia per axis terminus. Is this an evolutionary trend? How would you test your hypothesis? If the trend is real, what environmental conditions might favor this sort of evolutionary pattern?
2. Develop a phylogenetic hypothesis including the following taxa: Psilophyton, Pertica, Tetraxylopteris, Aneurophyton, Archaeopteris. How do you think this complex relates to the seed plants?
3. Why would Archaeopteryx never have used Archaeopteris as a roost?
4. How are the patterns of early seed plant evolution (morphological experimentation early in the history of the lineage) similar and different from those observed early in euphyllophyte evolution?

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