Chapter 41: Animal Nutrition Katie Dulak and Jared Peyton A.P Biology – 5th period V. Vilardi
All animals eat other organisms! 3 Types of Heterotrophs (organisms that don’t create their own food) Herbivores (consume autotrophs) Cows Carnivores (consume other heterotrophs) Lions Omnivores (Consume both autotrophs and heterotrophs) People This exemplifies what animals USUALLY eat. All Animals are opportunistic, meaning they’ll eat what they can get. (ie: cows will eat worms along with their grass)
See this lion? When it consumes this zebra in its entirety, it will also be consuming the organic plant material in its stomach.
Animals have 3 basic nutritional needs for their diets: • Fuel (chemical energy) • Organic raw materials (biosynthesis) • Essential nutrients, like vitamins and minerals, that the body cannot make on its own.
Check for understanding • What kind of feeder are you? • Can you think of another substrate feeder? • What are leeches considered?
Staying within budget… • Animals come naturally equipped with certain mechanisms that control how much energy an animal spends and where its spent. • The highest source of income for that budget is the production of ATP, which comes the metabolism of ingested foods via cellular respiration. • These foods provide, in descending order, the energy needed to make the body work: Fats, Carbohydrates, and Proteins.
Redistribution of Calories • When an excess of calories is consumed, the extras can go towards biosynthesis (ever hear the “growing boys” adage?) • If the animal is done growing, the calories are stored in “depots” (like the spare tire). • The liver and muscles store energy as glycogen, a major fuel source for cells, and the metabolism of such is a great example of homeostasis!
Breaking into the surplus • When less calories are consumed than burned, the body dips into the depots for energy. (Exercise, starvation) • Order of energy consumption (oxidation): • Liver Glycogen->Muscle Glycogen/Fat • The average person can live off of .3 kilograms of fat per day (several weeks of starvation before the energy sources run dry.
A budget out of balance • Undernourishment – the body runs out of fat and glycogen to run off of, so it begins breaking down its own proteins. Muscles decrease, and the brain becomes protein deficient. • This can be caused by starvation (seen in war stricken or impoverished nations, and places that suffer from drought). • It can also be caused by anorexia nervosa. • The detrimental effects, even if they don’t cause death of the organism, can be irreversible
Overnourishment (obesity) is the problem more common in the United States. • When extreme excesses of the body stores it in the form of fat. • In the case of carbohydrates, excesses increase rate of oxidation. Fat cell
Obesity is proven to be a factor in diabetes, colon and breast cancer, and pulmonary (heart) problems. • The body has homeostatic mechanisms designed specifically to regulate body weight. • Among these mechanisms are hormones, which are excreted by different organs and tissues of the body, that control hunger. • These hormones travel through the bloodstream to the brain to flip the switch between on and off in the “satiety center”
Stimulants: Ghrelin Suppressants: PYY, Leptin, Insulin
One wrong chromosome… • Researchers found that in some individuals, genetic mutations that causes abnormal leptin (from fat) production impact weight regulation greatly. Which mouse’s genes are a little too tight? *Hint: it’s the fat one. Why? He is suffering from a genetic mutation in which his body doesn’t produce enough leptin to maintain his hunger levels to keep that beach body.
Time for confusion • Those deemed “obese” have very high levels of Leptin in their body. • Leptin comes from fat, so it makes sense that people with excess fat have excess leptin, even though its supposed to be an appetite suppresant. • Heres the deal: just like the case SHOULD be with people eating, the brain only accepts certain concentrations of Leptin before it just refuses. *Someone hands you a piece of cake and you eat happily. Someone tries to force-feed you the entire cake, you shut your mouth and become extremely displeased.
Why is it that everything delicious is terrible for you? • Hamburgers and Pizza: Foods we love that are bad for you. Why must this be so? • At one point in time it might have been beneficial to stock up in foods high in fat. • Back in the days when our ancestors ran around in loincloths and lived in caves, they were hunters and gatherers with limited access to high-fat foods. So when they were available, it was necessary for the body to store the fat so there was something to sustain them during the times when the only accessible foods were berries and nuts. • Following Darwin’s Survival of the Fittest theory, those who had the capacity to store more fat had a higher chance of surviving, since they had that to live off of during times of famine. • Today, however, the only hunting and gathering people do is in the grocery store
The difference between man and beast • For some animals, storing fat and becoming, by our standards, obese, can be beneficial. • Animals that go through hibernation during the winter survive on their fat storages when food is scarce and the conditions do not favor locating food sources. • Also, animals that bring food to their young need this privilege. Storing the energy as fat helps the young to survive when food is scarce, and it helps the parents by not requiring them to carry as much.
Check for understanding • What does your body use to control hunger? • No having enough fat/glycogen leads to a condition called…? • And the opposite of that, having WAY too much is…? • What can obesity lead to?
Carbon Skeletons and essential nutrients • Biosynthesis: Formation of a chemical compound by a living organism • The raw materials of biosynthesis come from organism’s diets. • An organism takes these materials, called carbon skeletons, and uses them to create the complex molecules needed for growth. • Carbohydrates, proteins, and lipids are formed from the combination of organic carbons (like sugar) and a source of nitrogen (usually amino acids derived from the digestion of proteins).
Essential nutrients: substances obtained from the diet that the body can’t make on its own that’s necessary for health and development. • Some that are essential for certain animals aren’t for others. • Human beings have to obtain their vitamin C from their body, while goats make it on their own. • An animal lacking an essential nutrient is said to be malnourished.
The fantastic four • There are four classifications of essential nutrients: • Essential amino acids • Essential fatty acids • Vitamins • Minerals
Amino Acids • Animals require 20 amino acids to synthesize proteins, but only make about half on their own. • There are 8 essential amino acids for human beings, and the same is the case for most animals. • These are obtained through the diet. • A diet proividing an insufficient amount of any of these 8 amino acids leads to a form of malnutrition called protein deficiency. • The side effects of which include mental and physical retardation. • Effects of protein deficiency!
Kwashiorkor Due to protein deficiency, this little boy’s blood lacks the capacity to absorb water from the body properly.
Where to get it • The best sources of essential amino acids are meats, eggs, and cheese. • Animal proteins contain the perfect balance of pretty much all of the essential amino acids. • Plants individually have some amino acids, so the best way to make sure to get a sufficient amount of each is to figure out which plan has each amino acid, and arrange the diet accordingly
Meeting high demands • Some animals have adaptations that help them in times of great need. • Penguins, for instance, use muscle protein as amino acids to replace the proteins used during molting.
Fatty acids • Animals can produce MOST of the fatty acids they need, but not ALL. • (Those with double bonds) • Linoleic acid, for instance, is required for the production of some of the body’s phospholipids found in membranes, and is obtained through the diet. • Human and animal diets are usually overstocked in essential fatty acids, so deficiencies are rare.
Vitamins • Compared to essential amino and fatty acids, the required amount of vitamins for the body is fairly small. • These, however, follow by the rule of “speak softly but carry a big stick” • Vitamin deficiencies can cause HUGE problems. • 13 Essential vitamins have been identified and categorized as either “water-soluble” or “fat-soluble”. • An overdose in water-soluble vitamins is generally harmless, but overdosing in fat-soluble vitamins can lead to a build-up of toxic proportions.
Minerals • Minerals are inorganic materials needed in the animal diet. • Like vitamins, small amounts are needed, with exceptions like calcium* and phosphorous** (for bone development). *also necessary for the normal functioning of nerves and muscles, **also an ingredient of ATP and nucleic acids.
Warning!: Consuming minerals in excess can be potentially harmful! • The average human being consumes over 20 times the amount of salt required by the human body. • This much salt can upset the homeostatic balance and lead to bad side effects, like high blood pressure. • Iron too can be harmful, causing liver damage when overdosed on.
Check for understanding: • What are the 4 classifications of essential nutrients? • What is caused by insufficient amounts of essential amino acids? • What is the creation of internal chemical compounds from raw organic material called?
Food Processing: 4 easy steps • Ingestion: put food in your mouth. Chew it. Swallow it. You have ingested food.
Digestion: • In digestion, hydrolytic enzymes break down the food molecules small enough to be absorbed by the body. • The material in the foods are sorted out and shipped to their appropriate division: • Polysaccharides and disaccharides are split into simple sugars, • fats are digested to glycerol and fatty acids • proteins are split into amino acids • nucleic acids are cleaved into nucleotides
Absorption and Excretion • During absorption the materials sorted from digestion are sent to where they need to go. • It is during this stage that the body receives its daily dose of vitamin C (and all the other essential vitamins, minerals, and acids) • Excretion is the process by which the body eliminates the leftovers and waste through the digestive compartment.
Important Vocabulary: • Peristalsis: contraction and relaxation of muscles that push food through the digestion process. • Pepsinogen: Inactive enzyme • Hydrochloric acid: Gastric juice • Pepsin: Active enzyme created by the combination of pepsinogen and hydrochloric acid
If we eat organic materials…and the digestion process is primarily involuntary…how do we not eat ourselves? • Digestive compartments is the answer to that. • These specialized compartments safely house the food processing and ship the end result to where it needs to go.
Intracellular digestion • Food vacuoles engulf food materials through either phagocytosis or pinocytosis, and fuse with lysosomes to break it down without digesting the cell’s own cytoplasm. • This is the sponge’s only form of digestion, which is unusual in the animal kingdom.
Extracellular digestion • Digestion that occurs outside of the cells, which occurs in he gastrovascular cavity. • This functions in breaking down foods AND distributing the materials throughout the body (hence the vascular part).
Hydra digestion: Hydras sting their prey with nematocysts. Then they stuff the victim straight into their gastrovascular cavity. Specialized gland cells of the gastrodermis, the tissue layer that lines the cavity, then secrete digestive enzymes that break the soft tissues of the prey into tiny pieces. Other gastrodermal cells, called nutritive muscular cells, engulf these food particles. After a hydra has digested its meal, undigested materials remaining in the gastrovascularcavity are eliminated through the single opening, which functions as both mouth and anus.
The Digestive System • Digestive systems in most mammals are very similar. • Most have a digestive tube that extends from the mouth to the anus. This tube is called a complete digestive tract or an alimentary canal.
Movement of food in the canal • Peristalsis is the contractions of smooth muscles in the canal to move food • Ring-like valves called sphincters act like a draw string to enable this function.
Glands in the digestive system • Salivary Glands- secrete saliva into the oral cavity and help with swallowing food and other functions • Pancreas • Liver- produces bile and stores it in the gallbladder • Gallbladder- stores digestive juices
How we eat food • When food enters the mouth, or oral cavity, salivary glands secrete saliva into the oral cavity • Saliva helps protect the mouth from abrasions and makes food easier to swallow. • Saliva also neutralizes acid, and kills many of the bacteria that is in the food. • Actual digestion of carbohydrates begins in the oral cavity by the saliva
The tongue • The tongue plays a major role in eating food • It manipulates the food to chew it and helps you to swallow by pushing the food into the back of your throat into the pharynx
Pharynx • The Pharynx is space between the oral cavity and esophagus • It opens to the esophagus and windpipe • The epiglottis is a flap that prevents food from going into the windpipe