You simply want to describe things the way they are and then dynamics tells you how they changed and why they changed.

你只是单纯描述物体的实际状态,而动力学则是解释它们运动的方式和原因的

耶鲁公开课 - 基础物理课程节选

But if you throw off the environment, in this case, the animal's biology, it's drive for certain nutrients is in concert with the food it has access to.

如果让它们换个环境,这种情况下,这些动物的生理特性,即它们有多少动力去获取某些营养元素,是与其食物源状态有关的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选