Interactions Affect Survival Practice Test

Two bird species (Bird M and Bird N) eat the same type of insects in a woodland ecosystem. A model tracked nesting success (a reproduction outcome) when the species nested in separate areas versus the same area. Interactions between organisms can affect survival and reproduction. Use the evidence to answer: Which explanation best links the interaction to the reproduction outcome?

Data (same weather and same number of nesting sites):

• Separate areas: Bird M successful nests = $18/30$; Bird N successful nests = $20/30$
• Same area: Bird M successful nests = $9/30$; Bird N successful nests = $10/30$

In a forest ecosystem, a fungus lives on tree roots and helps trees take in nutrients. The model measured tree seedling survival with and without the fungus. Interactions between organisms can affect survival and reproduction. Use the evidence to answer: What evidence shows the effect of this interaction on survival?

Data (same rainfall and light):

• 100 seedlings with fungus: 78 survived after 6 months
• 100 seedlings without fungus: 41 survived after 6 months