Question

below is a food web from little rock lake, a freshwater lake ecosystem in wisconsin. which one of the following organisms eats a tertiary consumer in this food web? black crappie; green algae; golden algae; water flea

Explanation:

1. First, identify trophic levels:

• Producers: green algae, golden algae, water mold (make their own food)
• Primary consumers: water flea, copepod, rotifer (eat producers)
• Secondary consumers: backswimmer, whirligig beetle, water cricket (eat primary consumers)
• Tertiary consumers: shiner (eats secondary consumers like backswimmer)

1. Next, check which organism eats the tertiary consumer (shiner): the food web shows bacteria decomposes shiner, and black crappie preys on shiner. Among the options, only black crappie fits.
2. Eliminate other options: green algae and golden algae are producers; water flea is a primary consumer, none eat tertiary consumers.

Answer:

black crappie