AP Biology, Chapter 41
Animal Nutrition

SUMMARY
INTRODUCTION

NUTRITIONAL REQUIREMENTS
	Animals are heterotrophs that require food for fuel, carbon skeletons, and essential 
	nutrients: an overview
	Hoemostatic mechanisms manage an animal's fuel
		1. Compare the bioenergetics of animals when energy balance is positive and when it is 
		negative.
			a. Positive (more than enough nutrients)
				i. Allocate for growth and reproduction
				ii. Storage
					.Glycogen in the liver stimulated by insulin
					.Lipids in adipose
					.Excess carbohydrates converted to lipid
				iii. Increase leptin, decreasing appetite
			b. Negative
				i. Retrieval of stored material
					.Sugar from the liver stimulated by glucagon
					.Lipids from adipose
				ii. Recycling of muscle proteins
				iii. Decrease leptin, increasing appetite
	An animal's diet must supply essential nutrients and carbon skeletons for 
	biosynthesis
		2. Define essential nutrients and describe the four classes of essential nutrients.
			a. Essential
				i. Cannot be manufactured by the feeding organism
				ii. Vary widely: guinea pigs require C, mice do not
				iii. Also varies by age/development
			b. Classes
				i. Essential amino acids: 8/20 for humans
				ii. Essential fatty acids: linoleic for humans
				iii. Vitamins: 13 for humans
				iv. Minerals: Ca, Fe, K, P, Mg, etc.
FOOD TYPES AND FEEDING MECHANISMS
	Most animals are opportunistic feeders
	Diverse feeding adaptations have evolved among animals
		3. Compare the following types of feeders and note examples of each: suspension 
		feeders, substrate feeders, deposit feeders, fluid feeders, and bulk feeders.
			a. Suspension feeders: mainly aquatic, eat particles; bivalves, worms, baleen 
			whales
			b. Substrate feeders: live in or on their food; insects, earthworms
			c. Deposit feeders: substrate is soil/leaf litter; earthworms
			d. Fluid feeders: suck liquid nutrients; aphids, mosquitoes, vampire bats
			e. Bulk feeders: eat large pieces; you know who you are

OVERVIEW OF FOOD PROCESSING
	The four main stages of food processing are ingestion, digestion, absorption, and 
	Elimination
		4. Define and compare the four main stages of food processing.
			a. Ingestion: act of eating; teeth, lips, tongue
			b. Digestion
				i. Mechanical  smaller pieces
				ii. Chemical  break covalent bonds mostly using enzymes
			c. Absorption
				i. Small products of chemical digestion taken up by animal cells
				ii. By diffusion and/or active transport
			d. Elimination of undigested material from the digestive compartment
	Digestion occurs in specialized compartments
		5. Compare intracellular and extracellular digestion.
			a. Intracellular: in a membrane-bound space in the cytoplasm
			b. Extracellular
				i. In compartments that open to the environment
				ii. Gastrovascular cavity closes, enzymes/acid added
				iii. Alimentary canal
					.One direction
					.Specialized parts
					.Stepwise processing

THE MAMMALIAN DIGESTIVE SYSTEM
	Introduction
		6. Describe the common processes and structural components of the mammalian 
		digestive system.
			a. Muscle contraction
				i. Chewing
				ii. Peristalsis are waves of contraction that push food along
				iii. Segmentation involves alternating contractions of sections
				iv. Smooth muscle pumps vigorously
				v. Sphincters are circular muscles that close compartments
			b. Secretion
				i. From the walls of the organs
				ii. From accessory organs like salivary glands, pancreas, liver
			c. Absorption mainly in the small intestine
				i. Amino acids and sugars into capillaries
				ii. Fatty acids and glycerol into lacteals
				iii. Hepatic portal system carries blood to liver for filtering and 
				adjustment 
	The oral cavity, pharynx, and esophagus initiate food processing
		7. Compare the digestive processes of the major types of macromolecules.
			a. Complex carbohydrates
				i. Salivary and pancreatic amylases  disaccharides
				ii. Disaccharidases  monosaccharides
			b. Protein
				i. Pepsin in the stomach  small peptides
				ii. Trypsin, chymotrypsin  smaller polypeptides
				iii. Aminopeptidase, carboxypeptidase  amino acids
			c. Lipids
				i. Bile salts emulsify  fat droplets
				ii. Lipase  glycerol and fatty acids
			d. DNA and RNA
				i. Nucleases  nucleotides
				ii. Nucleotidases  nucleosides
				iii. Nucleosidases  bases, sugar, phosphate
	The stomach stores food and performs preliminary digestion
	The small intestine is the major organ of digestion and absorption
	Hormones help regulate digestion
		8. Explain how hormones influence the digestive process.
			a. Organ activities are coordinated by enteric nervous system and hormones
			b. Hormones
				i. Gastrin causes stomach to release acid
				ii. Enterogastrones made by the small intestine
					.Stimulate bicarbonate release from pancreas
					. Stimulate bile release from gallbladder
	Reclaiming water is a major function of the large intestine
		9. Describe the major functions of the large intestine.
			a. Absorb water
			b. House bacteria that process waste, produce vitamins, break down toxins
			c. Stores feces and controls its release

EVOLUTIONARY ADAPTATIONS OF VERTEBRATE DIGESTIVE SYSTEMS
	Structural adaptations of the digestive system are often associated with diet
		10. Relate variations in dentition and lengths of the digestive system to the feeding 
		strategies and diets of herbivores, carnivores, and omnivores.
			a. Dentition
				i. Incisors cut meat and vegetation
				ii. Canines pierce prey and rip meat
				iii. Premolars and molars grind plant material
			b. Length
				i. Carnivores have a shorter system with poorly developed large intestine 
				and much reduced cecum
				ii. Herbivores have a longer system with a long cecum and well-
				developed large intestine
				iii. Omnivores in between
	Symbiotic microorganisms help nourish many vertebrates