The answer to the first unknown is "Sensation" while in the second unknown is "Perception". These two words are very different such that the "sensation" is when the sense organ detected external physical stimuli but the "perception" is the processing, organizing and interpreting of those stimuli captured by sensation in the brain.
Basically when you got a drinking problem
It will screw the food web up because invasive species can take over and kill other species therefore eliminating one or more food sources that that environment had.
This is really open ended
but here is a possible answer
logical thinking and adequate assessment of the situation