7) Plant Defense

What does the idea 'Plants feed the world' imply?

All non-plants rely on plant food.

What is herbivory?

A widespread plant-animal interaction where insects feed on plants.

What are primary compounds?

Products of photosynthesis and protein synthesis that are essential for normal cellular function.

Give examples of primary compounds.

Carbohydrates, proteins, starches, cellulose, lignin.

What are secondary compounds?

Compounds with no known direct function in basic metabolism, often serving as chemical defenses.

Name some examples of secondary compounds.

Cyanide, strychnine, caffeine, mustard oil, morphine, and THC.

What is systemic defense?

A type of defense that is always present in a plant.

What is induced defense?

A type of defense that is triggered by an attack on the plant.

What are the two types of defenses plants can have?

Physical and chemical defenses.

What are examples of systemic physical defenses?

Thorns, spines, and visual deception or mimicry.

What is meant by 'visual deception' in plant defense?

Mimicry techniques such as fake insect eggs or fake damage spots to deter herbivores.

What are 'pebble plants' also known as?

Lithops, a plant that passively hides and is rarely eaten.

What is a 'sensitive plant' and how does it defend itself?

A plant that folds its leaves quickly to hide from herbivores.

Name a systemic chemical defense example mentioned in the lecture.

Poison ivy.

What is stinging nettle classified as?

A plant that exhibits both systemic physical and chemical defenses.

What is an example of induced physical defense?

Grass that defends against grazing pressure.

What is the role of induced chemical defenses in plants?

To make enzymes that reduce nutrient utilization and growth of herbivores after feeding.

What helps Cecropia trees in protecting themselves from herbivores?

Ant-bodyguard mutualism where ants are attracted to the tree by emitted gases.

What illustrates the arms race between plants and herbivores?

Herbivores evolving to bypass plant defenses in a co-evolutionary process.

How do monarch butterflies use milkweed toxins?

They are immune to the toxins and use them for their own protection against birds.

Why don't plants always maximize their defenses?

Defense is costly for the plant.

What compound do plants use as a warning signal for herbivore attacks?

Jasmonic acid.

What is the significance of plants having chemical complexity in their defenses?

It allows strict control over the synthesis of secondary compounds as defenses.

What is the relationship between herbivores and plant defenses in co-evolution?

Herbivores adapt to overcome plant defenses leading to an evolutionary arms race.

How does an induced defense differ from systemic defense?

Induced defenses are activated in response to an attack; systemic defenses are always present.

What is a common trait of induced chemical defenses?

They are often triggered by the physical damage caused by herbivores.

What is the function of trichomes in plant defense?

They serve as a physical barrier to deter herbivores.

What does 'active hiding' in plants refer to?

Defensive mechanisms like folding leaves quickly in response to threats.

What kind of mutualism involves Cecropia trees and ants?

Ant-bodyguard mutualism where ants protect the tree in exchange for food.

What is the purpose of secondary compounds in plants?

To act as chemical weapons against herbivores.

Can you name a chemical that serves as a defense mechanism in plants?

Quinine is one example of a secondary compound serving as a defense.