Question

what is the fundamental role of producers, such as tiny algae and seaweed, in the rocky shore food web?
they make their own food using sunlight and are the start of the food web.
they eat smaller animals like snails, limpets, and sea urchins
they regulate the population of mussels to maintain balance in the ecosystem.
they act as scavengers, consuming dead and decaying matter.
question 34
1 pts
why is the sea star classified as a keystone species in the rocky shore ecosystem?
it eats mussels, which prevents them from dominating the shore and allows other animals to survive.
it is a primary consumer that only feeds on rockweed and tiny algae.
it is an ectothermic animal that is highly sensitive to temperature fluctuations.
it is an indicator of pollution because it cannot tolerate oil or chemicals in the water.

Explanation:

First Question (Role of Producers in Rocky Shore Food Web)

• Producers (like algae, seaweed) perform photosynthesis, making their own food using sunlight. They are the base (start) of the food web as other organisms depend on them.
• The second option is incorrect because producers don't eat animals (consumers eat them or other consumers).
• The third option is incorrect as regulating mussel populations is a role of a keystone species (like sea stars), not producers.
• The fourth option is incorrect as scavengers consume dead matter, while producers make their own food.

• Keystone species have a disproportionately large impact on their ecosystem. Sea stars eat mussels, preventing mussels from overpopulating and outcompeting other species, which allows biodiversity.
• The second option is incorrect: sea stars are not primary consumers (they eat animals like mussels, so they are secondary/tertiary consumers, not herbivores feeding on algae/rockweed).
• The third option is incorrect: being ectothermic and sensitive to temperature is not related to being a keystone species.
• The fourth option is incorrect: being a pollution indicator is not the reason for being a keystone species (keystone relates to ecosystem structure, not pollution tolerance).

Answer:

A. They make their own food using sunlight and are the start of the food web.

Question 34 (Why Sea Star is a Keystone Species)