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Figure 10 (a) Water lilies have stomata on the upper surface of the leaves - Edexcel - GCSE Biology Combined Science - Question 5 - 2020 - Paper 1
Question 5
Figure 10 (a) Water lilies have stomata on the upper surface of the leaves. Explain why water lilies have no stomata on the lower surface of the leaves. (ii) Gluco... show full transcript
Worked Solution & Example Answer:Figure 10 (a) Water lilies have stomata on the upper surface of the leaves - Edexcel - GCSE Biology Combined Science - Question 5 - 2020 - Paper 1
Step 1
Explain why water lilies have no stomata on the lower surface of the leaves.
Answer
The lower surface of the water lily's leaves is submerged in water, which means it does not come into contact with air. This lack of exposure to air prevents gas exchange, as water cannot replace the gaseous exchange needed for processes such as transpiration. Thus, stomata are unnecessary on the lower surface.
Step 2
Step 3
Describe how this sugar is transported from the leaves to the flowers of the water lily.
Answer
Sucrose is transported from the leaves to the flowers through the phloem, a type of vascular tissue. This process occurs via active transport, where sucrose is loaded into the phloem at the source (leaves) and carried to the sink (flowers) through a pressure gradient, driving its movement.
Step 4
Explain why this non-indigenous plant now covers the whole surface of the lake.
Answer
The non-indigenous water lily likely proliferated due to favorable growth conditions, such as abundant sunlight, nutrients, and a lack of natural predators in the new environment. This allowed the plant to reproduce rapidly and spread across the lake surface, outcompeting local flora.
Step 5
Explain how the water lilies will affect the biodiversity of this lake.
Answer
The presence of water lilies can significantly impact biodiversity by dominating the aquatic environment, leading to reduced light penetration and altering the habitat for other species. As they spread, they may outcompete native plants, disrupt food chains, and reduce overall plant diversity, ultimately affecting fish and other wildlife that rely on native flora for habitat and food.