Learning Objectives:

1.A.2:  Natural selection acts on phenotypic variations in populations.

2.E.2:  Timing and coordination of physiological events are regulated by multiple mechanisms.

3.D.1:  Cell communication processes share common features that reflect a shared evolutionary history.

3.D.2:  Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.

3.E.2:  Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses.