SCI1186 Lecture Notes - Lecture 4: Cleaner Fish, Omega-3 Fatty Acid, Water Balance
16 Jun 2018
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Week 4 – Feeding and Digestion
TYPES OF FOOD
Food requirements:
• Animals require food to gain energy for vital processes
such as:
o Metabolic purposes
o Growth
o Reproduction
o Insulation (fat)
o Water balance
o Repair and maintenance
Types of animals:
• Animals eat a range of things, depending on their environment and body requirements
o Herbivores: eat only plants
o Carnivores: eat only meat
o Omnivores: eat both plants and meat
o Detrivores: lives in food sources (worms)
o Blood suckers
o Parasites
o Symbiotic relationships: two organisms living close
together in a mutually beneficial arrangement
(cleaner fish removing parasites from other fish)
Energy and essential nutrients in food:
• Animals require energy and essential nutrients from food
• Energy is used to drive metabolic processes and comes in the form of carbohydrates and lipids
• Main essential nutrients required are:
o Fatty acids (Omega 3 and 6)
o Amino acids, to make protein
o Water
o Vitamins
o Minerals
▪ 2 essential minerals:
1. Macroelements
o Cl and K (Nervous System)
o P (ATP processes)
o Ca and Na (bones)
2. Microelements
o Fe (red blood cells)
o Cu (protein and enzyme production)
o Co (thyroid)
o Mb
o Zn
o I
• Compared to plants, animals require organic nitrogen, more Na and Cl. Vertebrates also require I, Se and
Ca
Plant food:
• Mostly consist of carbohydrates with very low protein and sodium levels
• Plant carbohydrates are difficult to break down
• Glucose and fructose are easier to digest
• Cellulose, pectins, constitute fiber are difficult to digest and are used to move food throughout the plant as
they absorb water
Animal food:
• High in protein and low in carbohydrates
• The amount of food an animal eats depends on:
o Metabolic rate
o Stage of life cycle (juveniles require more energy than adults)
o How they feed (filter feeders need less energy)
o Environment (hibernating bear)
o Reproduction
• Small animals have a smaller metabolic rate compared to larger animals meaning they require less food
• The metabolic rate of a small animals compared to a big animal when looking at mass per kilogram shows
smaller animals have a faster metabolic rate
Document Summary
Food requirements: animals require food to gain energy for vital processes such as, metabolic purposes, growth, reproduction. Insulation (fat: water balance, repair and maintenance. 2 essential minerals: macroelements, cl and k (nervous system, p (atp processes, ca and na (bones, microelements, fe (red blood cells, cu (protein and enzyme production, co (thyroid, mb, zn. I: compared to plants, animals require organic nitrogen, more na and cl. Ingestion: is the first step in the digestion sequence. Digestion: the second step: digestion is the act of chemically breaking down food. Elimination: final step in digestion: pushes the waste from the small intestine into the large intestine, water is absorbed from the waste as it moves though the large intestine until it is excreted out of the anus. Extracellular digestive systems: found in multicellular organisms. Internal: found in most animals, requires either a gastrovascular cavity or an alimentary tract, occurs inside the body, external.
