Aerobic vs anaerobic
Technically speaking, the term ‘aerobic’ is an adjective that pertains to ‘requiring air’, particularly oxygen. Its counterpart, ‘anaerobic’ means ‘without air’ or not needing oxygen.  Evidently, these two terms are exact opposites. Their differences become more apparent as they are used in reference to cellular respiration, exercise and types of organisms.
In plants and animals, aerobic respiration is the chief process by which they utilize energy in the form of ATP or adenosine triphosphate. The key player in the generation of ATP would be oxygen, which also acts as the terminal electron acceptor. Aerobic metabolism is about 19 times more efficient than anaerobic metabolism. Conversely, anaerobic respiration is undergone by some microorganisms. Instead of oxygen, an inorganic acceptor such as sulfur is used as the final electron acceptor.
Moreover, aerobic organisms or aerobes are those that can live and grow in an environment where there is oxygen. There are four types of aerobic organisms. Obligate aerobes are those that require oxygen for cellular respiration in order to process energy. Facultative are those that partly utilize oxygen and partly rely on anaerobic methods. Microaerophiles may use minimal levels of oxygen. And lastly, aerotolerant can tolerate oxygen but don’t essentially need it. In contrast, anaerobic organisms or anaerobes are those not requiring oxygen for survival and growth. There are three types. Obligate anaerobes are those that don’t need oxygen at all and are even harmed by its presence. Aerotolerants are those which don’t use oxygen but can nonetheless stand it. Facultative aerobes would be those that can survive with or without oxygen.
As far as physical fitness and health are concerned, both aerobic and anaerobic types of exercises are essential to the body. Aerobic exercises hold close connection with how aerobic respiration works. They necessitate the use of oxygen to produce energy. On the contrary, anaerobic exercises make the body to produce energy without the help of oxygen. Aerobic exercises are relatively simple routines that can be performed for an extended period of time at moderate speed and intensity, thus requiring endurance above anything else. An aerobic exercise can be performed continuously for up to 20 minutes. They focus on strengthening the muscles, while helping improve blood circulation and pressure. They also help burn fat. During aerobic exercises, the energy is usually provided by carbohydrates and fats stored in the body.   On the other hand, anaerobic exercises are composed of more intense movements usually performed for shorter periods, probably 2 minutes. They put stress on muscle mass building, increasing muscle and bone strength, power, speed, as well as the metabolic rate. They help burn calories even when the body is in rest. In anaerobic exercises, energy comes from ATP and creatine phosphate.
Aerobic exercises include swimming, skiing, ‘aerobics’ dancing, rowing, skiing, brisk walking, jogging, and cycling. Heavier workouts such as weightlifting, boxing, and jumping are considered anaerobic exercises.

Summary

1. Aerobic and anaerobic are adjectives used in reference to organisms, cellular respiration and physical exercises. Aerobic pertains to ‘requiring air’, while anaerobic means ‘without air’.
2. Aerobic organisms can live and grow in the presence of oxygen, while anaerobic ones don’t necessarily require it to survive.
3. Aerobic respiration uses oxygen as the final electron acceptor in the generation of energy in the form of ATP. In anaerobic respiration, an inorganic acceptor such as sulfur is utilized. Aerobic metabolism is 19 times more efficient than anaerobic.
4. Aerobic exercises are simple routines that can be performed for an extended period of time. Brisk walking, swimming, cycling, and jogging fall in this category. Anaerobic exercises are intense workouts done in a shorter period. Examples are jumping, weightlifting and boxing.