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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) (ii) ... 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 have no stomata on the lower surface of the leaves because this area is submerged in water. As a result, the lower surface is not in contact with air, making gas exchange impossible. If stomata were present on the lower surface, it would not facilitate the exchange of gases like oxygen and carbon dioxide, which are essential for photosynthesis.
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 of the water lily through the phloem, a type of vascular tissue. The process occurs via a mechanism called translocation, which allows the movement of nutrients. Sucrose is loaded into the phloem at the source (the leaves) and flows to the sink (the flowers), utilizing pressure differences created by active transport and osmosis.
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 rate. Water lilies can reproduce vegetatively through rhizomes, spreading quickly and effectively. Furthermore, they may outcompete native species for sunlight, nutrients, and space, resulting in their domination over the lake's surface.
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. Their extensive coverage may reduce light penetration, impacting aquatic plants that require light for photosynthesis. This can lead to reduced populations of native species and alter the habitat structure. Additionally, water lilies can provide a habitat for certain species but may also displace others, leading to a decrease in overall biodiversity within the lake ecosystem.