Testing the Generality of Macroevolutionary Patterns with Bellerophont Molluscs

这个项目的主要目标是测试宏观进化参数在更大的群体中可能相当普遍的观点。Bellerophontiform软体动物与同时期的腹足类动物具有许多相同的外壳特征，尽管bellerophonform是两侧对称的，而早期的腹足类是不对称的。研究人员认为，这些特征中有许多对舌虫和不对称腹足类动物具有相似的生物学意义。如果是这样，那么PI期望在这些角色中看到类似的变化率以及类似的驱动趋势（即，特定角色状态的有偏见的产品）。他将使用作者设计的可能性方法来评估其他假设，同时测试系统发育和特征进化参数。在这样做的过程中，测试将评估bellerophonts的特征参数是否与不对称腹足类动物有显著不同，如果有，以何种方式。这项研究的第二个目标是测试有关bellerophons关系的基本观点，比如它们是单系还是多系，以及bellerophons与不对称蜗牛的亲缘关系有多密切。

The primary goal of this project is to test the idea that macroevolutionary parameters might be fairly general among larger groups. Bellerophontiform molluscs share numerous shell characters with contemporaneous gastropods even though bellerophonts are bilaterally symmetrical whereas early gastropods are asymmetrical. Workers consider many of these features to have similar biological implications for both bellerophonts and asymmetrical gastropods. If so, then PI expects to see similar rates of change in those characters as well as similar driven trends (i.e., biased productions of particular character states). He will evaluate alternative hypotheses using likelihood approaches designed by the author to simultaneously test phylogenetic and character evolution parameters. In doing so, tests will assess whether character parameters for bellerophonts are significantly different than for asymmetrical gastropods and, if so, in what ways. A secondary goal of the study is to test basic ideas about bellerophont relationships, such as whether they are monophyletic or polyphyletic, and ideas about how closely related bellerophonts are to asymmetrical snails.