BIO130H1 Lecture Notes - Lecture 10: Sandpaper, Herbivore, Cyclopamine
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BIO130H1 Full Course Notes
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The world is green because carnivores keep herbivore pop down so they don"t limit plant growth. Trophic cascades, one level affecting the next and so on. Indirect effects can be as strong as direct effects. Monarch butterfly larva = specialist at eating milkweed. Cuts leaf midrib to reduce sap pressure before eating. They don"t detoxify the poison, they put it in their cuticle, making themselves poisonous. Eating animals is easy to digest since it"s animal material like you. Graminoids (grasses, sedges) have meristem below the plant so can still grow right back even when eaten e. g. lawn mowing. Also are defended by mechanical defense (silica in them since it"s abrasive/like eating sandpaper). They"re broad-leafed and have chemical defenses using alkaloids/poisons. Cattle = ruminants = highly developed mammals to break down leaf material. Cow eats brings back to mouth, grind and swallow again. Horses not the same, grind in mouth and lets microbial digestion in cecum (appendix in humans).
