Unit 04: Animal Nutrition Flashcards
What is nutrition?
The balance between nutrient intake and the needs of the body.
What must diet provide?
1 - Chemical energy
2 - Organic molecules
Why do we need chemical energy from diet?
Food stores chemical energy which is then broken down, generating ATP which fuels cellular processes.
What are organic molecules and why do we need them?
“Raw” material like carbon or nitrogen which allows for biosynthesis of macromolecules (proteins, carbs lipids).
What are essential nutrients?
Nutrients that animals cannot make, must be obtained from diet.
What are the 4 classes of essential nutrients?
- Amino acids (complete vs incomplete proteins)
- Fatty acids ex. omega 3, 6, 9
- Vitamins (organic molecules) ex. B, C, D
- Minerals (inorganic molecules) ex. B C D
How many amino acids can we not synthesize?
8/20
What are some examples of complete and incomplete proteins?
Complete - meat, cheese
Incomplete - plants (variety is needed)
What are the four stages of food processing?
- Ingestion
- Digestion
- Absorption
- Elimination
What is the difference between elimination and excretion?
Elimination = pooping
Excretion = peeing
What are the four feeding mechanisms used by animals?
- Suspension/filter feeding
- Substrate feeding
- Fluid feeding
- Bulk feeding
Describe suspension feeding and list some animals that use this method of ingestion.
Sifting small food from water
Clams, baleen whales
Describe substrate feeding and list some animals that use this method of ingestion.
Living in/on food source
Maggots, caterpillars
Describe fluid feeding and list some animals that use this method of ingestion.
Sucking nutrient rich fluid from living host.
Mosquitos, bees, aphids
Describe bulk feeding and list some animals that use this method of ingestion.
Eating large chunks.
2 types:
Whole (swallow whole, modified jaws) - rock python
Pieces (tear food w claws, teeth, pincers, etc.) - humans
What is mechanical digestion?
Breaking food into smaller pieces, increasing surface area, allowing for a higher rate of digestion.
What is an adaptation in mammals allowing for more effective mechanical digestion?
Teeth.
What are the 4 types of teeth and what are they used for?
Incisors (front) - thin and flat for biting and cutting
Canines (fangs) - sharp and pointy to kill
Premolars - sharp to shred
Molars - flat surface for grinding
Describe the distribution of each tooth type in different diets.
Omnivore - equal distribution
Carnivore - large incisors and canines, many premolars, reduced molars
Herbivore - Reduced incisor and canines, premolars and molars used for grinding
Define chemical digestion.
Enzymes splitting food into smaller molecules for absorption.
What are the 2 types of chemical digestion? Define them.
Intracellular (atypical) - cells engulf food particles which are broken down by enzymes in vacuole
Extracellular (typical) - food broken down by enzymes inside of cells in chambers continuous with outside of body (alimentary canal)
What is a digestive cavity and which animals have them?
A digestive tract with one opening, mouth and anus are the same hole, so food moves one way then back. Able to digest and distribute nutrients.
In simple body plans, platyhelminths, cnidarians
What is a digestive canal and which animals have them?
Digestive tube with 2 openings (mouth AND anus).
Food moves in one direction with ordered, specialized regions for digestion and absorption.
Found in more complex body plans.
What are the 2 main components of a mammalian digestive system?
An alimentary canal and accessory glands that secrete digestive juices through ducts.
What are the mammalian digestive accessory glands?
Salivary gland, pancreas, liver, gall bladder.
What enzyme breaks down carbohydrates and in what part of the digestive tract is it found?
Amylase - found in mouth, pancreas, small intestine
What enzyme breaks down protein and in what part of the digestive tract is it found?
Proteases (mix of pepsin and acids) - found in stomach, pancreas and small intestine.
What enzyme breaks down lipids and in what part of the digestive tract is it found?
Lipases (in bile) - found in pancreas, which release enzyme into small intestine
How many bacterial species are there in the human digestive tract?
> 400
Describe an adaptation in the human digestive system which has increased surface area, allowing for higher absorption efficiency.
Small intestine!
Small intestine is 6 feet long, projections of folds called villi on small intestine increase SA x 10.
On the villi there are epithelial cells which have microvilli on them increasing SA x 50
What is the approximate surface area of the human small intestine?
300m^2
What is mutualistic symbiosis?
Mutually beneficial interaction between species
What do animals have a hard time digesting (think plants)
Cellulose (plant tissue)
How do animals digest cellulose?
Fermentation chambers which allow for food storage and digestion of cellulose by bacteria and protists.
What is the fermentation chamber to break down cellulose in bids called and where is it located?
Crop - located right before stomach
What is the fermentation chamber to break down cellulose in mammals called and where is it located?
Cecum - at the base of the ascending part of the colon (start of the colon, right beside appendix)
Describe the correlation between digestive tract length and diet for herbivores.
Plant tissue is harder to digest, herbivores eat smaller amounts at a time, so stomach is smaller
Large intestine is longer with higher SA and larger cecum.
Describe the correlation between digestive tract length and diet for carnivores.
Animal tissue easier to digest, so carnivores eat larger meals, therefore stomach is larger and able to expand.
Large intestine is shorter and smaller cecum.
Explain how ruminants eat food.
- Chew food which goes into stomach chambers 1 and 2 where cellulose is digested by microorganisms.
- Cud regurgitated and chewed
- Cud is swallowed going into chamber 3 where water is absorbed.
- further digestion in chamber 4
What morphological trait do all ruminants have in common.
4-chambered stomach
What animals are ruminants.
Deer, cow, sheep
What is coprophagy and name an animal that does it.
When animals eat feces to recover unabsorbed nutrients.
Rabbits
What harmful byproduct of digestion is specifically due to protein breakdown.
Ammonia
What are the different forms of ammonia that an animal may excrete and which animals excrete it.
- Ammonia - most toxic, high water loss, little energy required. Aquatic species.
- Urea - medium toxicity, medium water loss, medium energy loss. Land species.
- Uric acid - low toxicity and water loss, higher energy costs. Land reptiles, birds.
Describe the first step in the process of excretion and where it occurs.
Filtration.
Excretory tubule collects a filtrate (small molecules like water, NH3, salts) from blood.
Passive
Describe the second step in the process of excretion and where it occurs.
Reabsorption.
Transport epithelium selectively reclaims valuable solutes (water, sugar, a^2) and returns to bodily fluids.
Describe the third step in the process of excretion and where it occurs.
Secretion.
Toxins and non-essential solutes are added to filtrate from blood.
Describe the fourth step in the process of excretion and where it occurs.
Excretion.
Filtrate (urine) leaves body.
Describe a simple system network of tubules.
Network of dead-end tubules found in connected to external openings (ex. flatworms)
Describe a complex system network of tubules.
Open ended tubules that collect fluid from coelom and produce urine. There is a pair/segment.
Ex. annelids
Describe the second most complex system network of tubules.
Malpighian tubules (tubules w dead end tips) that collect molecules from hemolymph which then go to digestive tract where solutes are reabsorbed.
This produced a dry paste in the hindgut (uric acid)
Ex. insects (grasshoppers)
Describe the most complex system network of tubules.
Nephrons - long tubules that are very close in proximity to capillaries that span inner and outer kidney.
Carry and process filtrate produced by blood entering kidney.
