16.3 Plant responses to herbivory

Question 1

what is herbivory

Answer 1

• herbivores eat plants
• plants produce chemicals which act as a repellent to animals (sometimes poisonous)
• sometimes the chemicals are always present and other times, they get produced in response to stress

Question 2

describe tannins

Answer 2

• water soluble flavonoids
• stored in vacuoles, fatal to insects as they are toxic when broken down
• bitter taste

Question 3

describe alkaloids

Answer 3

• nitrogenous compounds from amino acids
• bitter taste
• can be toxic
• e.g. caffeine and nicotine
• e.g. capsaicin in chillies

Question 4

describe pheromones

Answer 4

• chemicals released by a species to affect another organism in the same species
• ethene released by plants causes ripening of fruit in nearby plants and/or leaf loss
• oxides of ethene are toxic to insects
• controls other chemical defences in plants (switches on genes that produce chemicals to deter insects and therefore is a hormone)