Digestive systems take many forms. There is a fundamental distinction between internal and external digestion. External digestion developed earlier in evolutionary history, and most fungi still rely on it. In this process, enzymes are secreted into the environment surrounding the organism, where they break down an organic material, and some of the products diffuse back to the organism. Animals have a tube (gastrointestinal tract) in which internal digestion occurs, which is more efficient because more of the broken down products can be captured, and the internal chemical environment can be more efficiently controlled. COUNT 5
QSN1 What are the two types of digestion? ANS1 internal and external digestion QSN2 When did external digestion develop? ANS2 earlier in evolutionary history QSN3 What still uses the external digestion system? ANS3 most fungi QSN4 What is the name of the tube that helps add in animal digestion? ANS4 gastrointestinal tract QSN5 Why is internal digection better than external? ANS5 more of the broken down products can be captured, and the internal chemical environment can be more efficiently controlled