Negative impact on the environment is unnatural, fake
When a stimulus is produced it signifies the production of sensation in the sensory organs. This sensation through the sensory organs (eyes, ears, nose, skin and tongue) is sent to the sensory nerve connected to these sense organs. These sensory nerves send nerve impulses through the nerve fiber to the spinal cord. From the spinal cord the nerve impulse is transferred to motor nerves.
The motor nerve then sends response to the stimulus though the same path to the region from which stimulus was received and thus the body responds through muscular activity. Such as removal of heat from the heated object if heated sensations were received.
They decrease because the zebra mussel were taking their resources. Leaving them nothing to eat.
Answer:
The Doctrine of Specific Nerve Energies has been and continues to be enormously influential in the physiology, psychology, and philosophy of perception. In simple terms, the Doctrine states that we directly perceive in the first instance the activity of our nerves, rather than properties in the external world.