Fig. 1 shows a food web from a lake beside farmland. Algae use carbon dioxide, water and light to make food. Snails and water fleas eat algae. Perch eat wat...
Question 1 Report
Fig. 1 shows a food web from a lake beside farmland. Algae use carbon dioxide, water and light to make food. Snails and water fleas eat algae. Perch eat water fleas, and herons eat perch. The farmer plans to remove reeds from the lake edge to make space for a path. Reeds provide shelter for young perch.
(a) Name the producer in this food web. [1]
(b) Use Fig. 1 to write one food chain containing four organisms. [2]
(c) Suggest how removing reeds could affect the heron population. [2]
(d) Describe the role of decomposers after a perch dies. [1]
Answer Details
Labelled answer diagram:
(a) Algae are the producer [1]. Producers make their own biomass by photosynthesis, and the stem states that algae use carbon dioxide, water and light to make food.
(b) A four-organism food chain is algae → water fleas → perch → heron [2]. The arrows show energy transfer from the organism being eaten to the consumer.
(c) Removing reeds gives young perch less shelter, so more young perch may be eaten [1]. This can reduce the perch population; herons would then have less perch available as food, so heron numbers may decrease [1].
(d) Decomposers break down the dead perch and release mineral ions, recycling nutrients in the ecosystem [1].
Download The App On Google Playstore
Everything you need to excel in your exams
