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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. (2) (i... 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
Water lilies do not have stomata on the lower surface of their leaves because this surface is submerged in water. Since the lower surface is not exposed to air, gas exchange cannot occur. Water and gases, like oxygen and carbon dioxide, enter through the upper surface where the stomata are located.
Step 3
Describe how this sugar is transported from the leaves to the flowers of the water lily.
Answer
The sugar, sucrose, is transported from the leaves to the flowers through the phloem tissue. Phloem transports sugars produced in the leaves during photosynthesis to other parts of the plant, including flowers, using a process called translocation. Sucrose is actively transported into the phloem, creating a concentration gradient that drives the flow of the sugar solution.
Step 4
Explain why this non-indigenous plant now covers the whole surface of the lake.
Answer
The non-indigenous water lily plant likely covers the whole surface of the lake due to its rapid growth and reproductive capability. As an introduced species, it may not have natural predators or competitors in this new environment. Consequently, the water lily can spread quickly, utilizing available resources effectively, leading to dominance over native species.
Step 5
Explain how the water lilies will affect the biodiversity of this lake.
Answer
The presence of water lilies can significantly affect the biodiversity of the lake by dominating the surface area. This can reduce light penetration into the water, impacting aquatic plants and altering habitats for fish and other organisms. Furthermore, the expansion of water lilies could lead to decreased oxygen levels in the water, detrimental to the survival of various species, thereby reducing overall biodiversity.