Question

population models
models can be many things. the four graphs you see here are population models. all four graphs have something in common. what is it?
a. the graphs show exponential population growth.
b. each graph shows the birth and death rates over time.
c. each graph shows the change in population(s) over time.
d. all four graphs show how species compete for resources.
population growth or population dynamics? consider graph d. what type of relationship is indicated by this population model?
a. competition
b. mutualism
c. parasitism
d. predator - prey

Explanation:

• First question:
• Analyze each option:
• Option A: Graphs like C (which shows oscillations) and D (shows a relationship between two species) do not show exponential growth. So A is wrong.
• Option B: The graphs do not show birth and death rates separately. They show population - related changes. So B is wrong.
• Option C: Graph A shows human population over time, B shows bald - eagle population over time, C shows some population (maybe of a species with oscillating population) over time, and D shows the relationship between two species' populations over time. So C is correct.
• Option D: Only graph D (if it's about two species) might hint at some interaction, but not all graphs show species competing for resources. So D is wrong.
• Second question:
• Analyze each option:
• Option A: Competition usually has a more symmetric negative impact on both species (if it's inter - specific competition). But graph D (assuming it's a predator - prey graph) is not competition.
• Option B: Mutualism would show both species benefiting and their populations increasing together. Graph D does not show this.
• Option C: Parasitism is a one - sided relationship where one benefits (parasite) and the other is harmed (host). Graph D is more of a predator - prey.
• Option D: In a predator - prey relationship, when the prey population increases, the predator population has more food and can increase. Then, as the predator population increases, it preys on more prey, causing the prey population to decrease. This leads to a decrease in the predator population (due to lack of food). Graph D (assuming the typical predator - prey graph shape) shows this relationship.

Answer:

• First question: C. Each graph shows the change in population(s) over time.
• Second question: D. predator - prey.