When a neuron sends information down the axon, is called an ___ ___ (two words) also known as a spike or impulse.

2. Darwin also named some factors that affect the process of natural selection. Among these were overproduction, competition, and variations. Overproduction happens when species reproduce many more offspring than can possibly survive. ... Those who are better able to survive then pass on their genes to their offspring.

3. Evolutionary change can occur through mutation and natural selection. Mutations are genetic changes in an organism. ... Even though outside factors can cause mutation to occur, what kind of genetic change will occur is random. Mutations can be harmful, beneficial, or neutral.