BIOL 1902 Lecture : wk 7.doc
Document Summary
Live plants as food: all parts of plants are food for animals. Physical problems to overcome: tough tissues due to structural components. Adaptations to break off and then break up: snails and slugs: have radula, insects: caterpillars, grasshoppers have mandibles that slice, A) incisors to cut off pieces of plants. Beavers and other rodents - constantly grow and self- Sharpen by: rubbing against each other, structure: dentine and enamel - wear differentially. B) cheek teeth = molars, premolars grind and crush. Muscles: huge masseters to power grinding: birds: spruce grouse eats spruce needles - really tough. Ground in gizzard = muscular stomach compartment with. Birds add grit (small stones) to gizzard by eating them. Analogous structures = same function but a different origin. Gizzard, radula, mandibles, cheek teeth all grind and break up plant. Material but all are different parts of the body = analogous. Digestion = breakdown of the structural elements like cellulose.