Question

Rotifers and water fleas are predatory omnivores, eating phytoplankton, bacteria, and other microorganisms. Two flasks are prepared. Both flasks contain rotifers and phytoplankton, but Flask Z also contains water fleas.This graph shows the populations.Line graph: Rotifer populations over 18 days. X axis: Day 0-18. Y axis: Number of rotifers, 0-4500. Showing rotifers alone and with water fleas.Analyze the graph and identify some factors that may contribute to the rotifer population leveling off in the absence of water fleas. Explain your answer in 1–2 sentences.

Answer 1

The rotifer population likely levels off because density-dependent limits (reduced phytoplankton/bacterial food and increased competition) lower birth rates and raise mortality as carrying capacity is reached. Additional factors like waste accumulation, limited space, or disease at higher densities could also contribute.