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较大群体中可能相当普遍的想法。 Bellerophontiform软体动物与同时代的腹足动物共享许多外壳特征，尽管Bellerophonts是双侧对称的，而早期腹足动物是不对称的。 工作人员认为这些特征中的许多特征对bellerophonts和不对称的腹足动物都有类似的生物学意义。 如果是这样，那么PI期望看到这些字符的相似变化率以及相似的驱动趋势（即，特定字符状态的有偏产生）。 他将使用作者设计的可能性方法来评估替代假设，以同时测试系统发育和特征进化参数。 在这样做的时候，测试将评估是否bellerophonts的字符参数是显着不同的不对称腹足类动物，如果是这样，在什么方式。 这项研究的第二个目标是测试关于bellerophont关系的基本观点，例如它们是单系还是多系，以及bellerophont与不对称蜗牛的关系有多密切。

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.