Responses to the Environment: Practice Questions

Which of the following scenarios best illustrates the concept of kin selection in an ecological context?

Two species of seed-eating finches inhabit the same island. Over time, Species A evolves a larger beak to crack tough seeds, while Species B evolves a smaller beak to forage for tiny seeds. This divergence in morphology and resource use is best described as:

In an aquatic ecosystem, the biomass of the primary producers (phytoplankton) is often less than the biomass of the primary consumers (zooplankton) at any given moment. Which of the following explains this "inverted" biomass pyramid?

The graph of a population's size over time shows an initial lag phase, followed by a rapid exponential growth phase, and finally levels off as it approaches a horizontal asymptote. What does this horizontal asymptote represent in ecological terms?

In a specific forest ecosystem, the net primary productivity (NPP) is measured at \(2000\text{ g/m}^2\text{/yr}\). If the respiration by autotrophs (Ra) is \(1500\text{ g/m}^2\text{/yr}\), what is the gross primary productivity (GPP) of this ecosystem?

A researcher measures the primary productivity of a lake ecosystem. If the Gross Primary Productivity (GPP) is measured as \( 4.5 \text{ mg O}_2/\text{L}/\text{day} \) and the respiration rate of the producers is \( 1.8 \text{ mg O}_2/\text{L}/\text{day} \), calculate the Net Primary Productivity (NPP) and describe how this value limits the number of trophic levels in the food web.