Lecture 4: Animal Nutrition I
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Animal Nutrition I (Ch. 41) Keywords • • • • • • • • Heterotroph Autotroph Herbivore Carnivore Omnivore Intracellular digestion Food vacuole Extracellular digestion • Gastrovascular cavity • Alimentary canal • Basic parts of alimentary canal • Roles of mouth and stomach in digestion Some of the best known and fascinating adaptations of animals involve their feeding and digestion Examples: • Reptile swallowing prey • Baleen whales Python Starfish Chiasmodon niger Cryptopsaras couesi Eurypharynx pelecanoides Categories • I. Autotroph • II. Heterotroph – A. Herbivore – B. Carnivore – C. Omnivore Today we’ll focus on heterotrophs: Digestion • Basic principles • Invertebrates • Humans Why is digestion necessary? • Macromolecules cannot easily enter cell COO- NH3+ cytoplasm peptide Cell membrane Small molecules such as amino acids can cytoplasm Peptide being digested Cell membrane cytoplasm Peptide being digested Cell membrane cytoplasm Peptide being digested Cell membrane cytoplasm Peptide being digested Cell membrane cytoplasm Digested peptide Cell membrane Even if macromolecules are taken in… COO- NH3+ cytoplasm peptide Cell membrane Even if macromolecules are taken in… cytoplasm COO- peptide Cell membrane NH3+ They cannot be readily incorporated cytoplasm COO- Food peptide Cell membrane NH3+ New peptide Unless broken down first cytoplasm Food peptide Cell membrane New peptide Unless broken down first cytoplasm Food peptide Cell membrane New peptide Unless broken down first cytoplasm Food peptide Cell membrane New peptide This lecture will focus on how animals break down food • I. Intracellular digestion – A. food vacuoles • II. Extracellular digestion – A. outside organism – B. gastrovascular cavity – C. alimentary canal I. Intracellular digestion • A. food vacuoles Intracellular digestion without vacuoles Intracellular digestion without vacuoles Intracellular digestion with vacuoles Intracellular digestion with vacuoles Intracellular digestion with vacuoles Digestion in Paramecium Intracellular digestion vs. Extracellular digestion Extracellular digestion • A. outside organism • B. gastrovascular cavities • C. alimentary canal Extracellular digestion • A. outside organism • B. gastrovascular cavities • C. alimentary canal Gastrovascular cavity: Hydra Extracellular digestion • A. outside organism • B. gastrovascular cavities • C. alimentary canal Gastrovascular cavity vs. Alimentary Canal Alimentary canal: a simple view Basic parts of alimentary canal Mechanical digestion mouth storage absorption anus Alimentary canal: mammalian Mouth • Mechanical • enzymatic Stomach Digestive mechanisms in stomach • Mechanical • Chemical • enzymatic
