SSCE VCE Biology Genetic Diversity and Adaptations: Question 3
Herbivores can cause

Question

Question 3
Herbivores can cause damage to the leaves, flowers and fruits of plants. In response, a plant may drop the affected part. This process of 'dropping off' parts by a plant is called abscission.

a. Name the plant hormone responsible for plant abscission.

1 mark

Some Physalis plants abscise fruit containing larvae of a moth predator, Heliothis subflecta. To complete development, H. subflecta larvae need to feed off more than one fruit. For this to occur, larvae from dropped fruit must relocate and climb onto a new host plant.

An experiment was performed to determine the effectiveness of the abscission strategy for plants.

Two different species of Physalis were used.

Species 1: P. pubescens - a low shrub with drooping, spreading branches
Species 2: P. angulata - a tall shrub with upright stem and branches

Different sized larvae were used:
- larvae at early stage development - 15 mm long
- larvae at late stage development - 30 mm long

Each species of plant was tested with two different sized larvae.
The results obtained are summarised in the following graph.

b. 
i. Which species of Physalis is more susceptible to relocation by H. subflecta larvae?

ii. From the information given suggest a reason why.

Question 3 Herbivores can cause damage to the leaves, flowers and fruits of plants - VCE - SSCE Biology - Question 3 - 2011 - Paper 1

Worked Solution & Example Answer:Question 3 Herbivores can cause damage to the leaves, flowers and fruits of plants - VCE - SSCE Biology - Question 3 - 2011 - Paper 1

a. Name the plant hormone responsible for plant abscission.

b. i. Which species of Physalis is more susceptible to relocation by H. subflecta larvae?

b. ii. From the information given suggest a reason why.

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