BIOA02H3 Lecture Notes - Lecture 12: Arms Race, Herbivore, Kalahari Desert
BIOA02 Module 1 Lecture 12: Plant Defense
Plant Defense
• Plants feed the world but they do not really want to do so
• Plant defense mechanisms
• Arms race between plants and herbivores
Plants feed the world
• All non-plants depend directly or indirectly on plant food
• Every plant is under constant threat of attack
Herbivory
• Most widespread plant-animal interaction often least visible
• Insects: feeding on plants day and night
Mechanical defense: grows organs or tissues
• Slower to react
• Is grown from the start
Chemical defense: toxins around poisons are produced
• Can be fast to react
Primary vs Secondary Compounds
• Primary Compounds: products of photosynthesis, protein synthesis
o Carbohydrates, proteins, starches, cellulose
o Essential to normal cellular function and life in general
• Secondary Compounds: products have no known direct function in basic metabolism
Role of Secondary Compounds
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Document Summary
Plant defense: plants feed the world but they do not really want to do so, plant defense mechanisms, arms race between plants and herbivores. Plants feed the world: all non-plants depend directly or indirectly on plant food, every plant is under constant threat of attack. Herbivory: most widespread plant-animal interaction often least visible. Mechanical defense: grows organs or tissues: slower to react. Chemical defense: toxins around poisons are produced: can be fast to react. Primary vs secondary compounds: primary compounds: products of photosynthesis, protein synthesis, carbohydrates, proteins, starches, cellulose, essential to normal cellular function and life in general, secondary compounds: products have no known direct function in basic metabolism. Role of secondary compounds: huge complexity of compounds, strict control of synthesis, chemical weapons against herbivores. Plant defense against herbivory: defense can be always present = systemic. Induced by herbivore attacks: physical defense: mostly systemic, chemical defense: often induced. Passive hiding: lithops: pebble plants, kalahari desert, rarely if ever eaten.