Describe some of the effects that dilated blood vessels will have on blood pressure.

describe some of the effects that expanded blood vessels will have on blood pressure.

Since pressure is force per unit area, blood pressure could be thought as the force exerted by the blood to the surface area of your blood vessels. When your blood vessels dilate, it means that they expanded. The result would be faster flow of blood. When this happens, the force of the blood is not any more concentrated on your blood vessels because there is more room available. 

Think of a faucet where tap water flows. When you stopper the faucet with your finger, you feel the force of the water. The pressure builds up as manifested by the sound your faucet makes. But when you release your finger, the water rushes through and flows faster. The pressure is released. Therefore, when your blood vessels are dilated, your blood pressure decreases.

Cladistics is concerned with entire branchings. This way groups all the descendants from a common radiation into a clade as a related group and no others. The clades are monophyletic. This is a narrower definition of an older, less precise concept.

Phylogeny is a way of tracking evolutionary relationships based on shared characters. Originally this used Linnaeus' artificially defined levels of taxonomy. This method allows convergent characters to be grouped despite their having followed a separate evolutionary path. Taxonomy is the rank levels while phylogeny is the path through the ranks.

Cladistics is a way of grouping the related branches based on sharing derived characters within the group. However these characters are not found in other species except by convergence.