90 likes | 323 Views
Comparative Digestive Systems. Biology 11 G.Burgess 2006. Digestion. The breakdown of nutrient materials into smaller absorbable particles. There are two main forms of digestion Mechanical Digestion: breaking down of materials physically (ie. Chewing food)
E N D
Comparative Digestive Systems Biology 11 G.Burgess 2006
Digestion • The breakdown of nutrient materials into smaller absorbable particles. • There are two main forms of digestion • Mechanical Digestion: breaking down of materials physically (ie. Chewing food) • Chemical Digestion: breaking down of materials by adding acids, bases and enzymes (ie. Salivary amylase breaks down starch into maltose in your mouth)
Unicellular organisms • Most unicellular organisms do not require digestion because most of their nutrients are already small enough to be absorbed into the cell • However, some, like the paramecium are able to bring in solid particles as food vacuoles. These use lysosomes (packed with hydrolytic enzymes) to breakdown the contents of the food vacuoles.
Plants • Plants and other autotrophic organisms do not always require digestion. • As always, there are exceptions • Plants that cannot get nitrogen from the soil (ie. Venus fly trap or pitcher plant), get nitrogen by digesting insects in specialized leaf structures that secrete digestive enzymes.
Multicellular organisms • Multicellular organisms have a variety of specialized digestive organs. • Annelids (ie. earthworm) have a series of organs for digesting • Mouth, pharynx, esophagus, crop, gizzard, intestine • Orthopterans (grasshoppers) use the same type of digestive parts as the earthworm, however, they also have an organ called the gastric caeca. • Amphibians (frog) also have much the same type of digestive organs, however, they do not have a crop or gizzard. Instead, they have a stomach. • Each of these organisms also have specialized mouth parts so that they can eat their natural foods.
Earthworm Digestive System • Pharynx • Mouth • Esophagus • Crop • Gizzard • Intestine • Anus
Grasshopper Digestive System Mouth Crop Esophagus Gizzard Intestine Anus
Frog Digestive System • Esophagus • Stomach • Liver • Galbladder • Intestine • Cloaca • Anus
Human Digestive System • Mouth • Pharynx • Esophagus • Liver • Gallbladder • Stomach • Small intestine • Large intestine • Rectum • Anus