Lecture 7 - Nutrition and the digestion system

Have mulpurpose set of teeth carnivores have greatly

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Unformatted text preview: , neuropathy and death 23 High food consump,on •  Overnourished –  Increase in nutrients are stored as increased body mass –  Needed for animals that go through hiberna,on –  In humans is a hazardous health problem (36% US popula,on is considered obese) •  High risk of diabetes, heart problems and stroke 24 How do animals acquire their nutri,on? •  Carnivorous –  Consume animal flesh or fluids •  Herbivores –  Eat only plants •  Omnivores –  Eat both plants and animals •  Saprobes –  Absorb nutrient from dead organic maaer (e.g. pro,sts and fungi) 25 How animals acquire their nutri,on? •  Fluid feeders –  e.g. mosquitoes, aphids, leeches and hummingbirds –  Do not need teeth •  Filter feeders –  e.g. clams and whales –  Prey on small organisms by filtering them from aqua,c environment 26 Adapta,ons for feeding •  Herbivores’ food is onen low in energy and hard to digest –  Diges,ve systems have evolved to increase the amount of nutrients intake –  Sedentary lives •  Carnivores must detect, capture and kill prey –  Stealth, speed, power, large jaws, sharp teeth, and strong gripping appendages –  Detec,on of prey 27 Adapta,ons for feeding •  Vertebrates teeth have adapted for the type of food they ingest –  Omnivores have mul,purpose set of teeth –  Carnivores have greatly enlarged canine teeth –  Herbivores use their incisors and canines to tear leaves of plants. Large molars for grinding 28 Adapta,ons for feeding •  We are what we eat and our bodies have been adapted for that 29 Diges,on and absorp,on • Intracellular diges,on –  Only in some very simple invertebrates (sponges and some single ­celled organisms) –  Uses phagocytosis to bring food par,cles directly into a cell –  Cannot meet metabolic demands of ac,ve animal for long –  No mechanism for storing food 30 Diges,on and absorp,on •  Extracellular diges,on –  Body cavity that is con,nuous with...
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This document was uploaded on 03/05/2014.

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