Here are some important vocabulary words mentioned in the video above:
- respiration: the intake of oxygen and the ejection of carbon dioxide
- countercurrent exchange: the exchange of a substance between 2 fluids flowing in opposite directions
- tracheal system: an internal respiratory organ composed of air tubes that branch throughout the body
- ventilation: when a substance (water or air) moves over the respiratory organ to help gas exchange
- alveoli: moist air sacs at the tips of the smallest tubes in the lungs
- positive pressure breathing: air is pushed into the lungs
- negative pressure breathing: air is pulled into the lungs
Below is a comparison of the three main types of respiratory mechanisms. The commonalities between the types indicate that aquatic and terrestrial animals likely evolved from a common ancestor.