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Difficulty: MediumEcology and Environment

Ecological relationships define how different species interact and influence one another within a biological community. Match each ecological interaction type on the left with the real-world scenario on the right that best demonstrates it.

  • MutualismRhizobium bacteria convert atmospheric nitrogen into usable nitrates inside clover root nodules while receiving carbohydrates produced by the plant.
  • CommensalismBarnacles attach to the outer skin of a baleen whale to access nutrient-rich feeding currents without causing harm or providing benefit to the whale.
  • ParasitismMistletoe penetrates the vascular tissue of a host oak tree, extracting water and vital mineral nutrients while weakening the tree.
  • CompetitionTwo predatory bird species hunt the same small rodent population in an overlapping woodland habitat, reducing resource availability for both.

Answer

Mutualism matches with Rhizobium bacteria trading nitrogen for plant carbohydrates (+/+); Commensalism matches with barnacles gaining feeding access on whale skin without affecting the whale (+/0); Parasitism matches with mistletoe siphoning water and nutrients from a host tree (+/-); Competition matches with two predatory bird species vying for the same rodent prey (-/-).
Each ecological interaction is classified by the net outcome experienced by both interacting species: mutualism is (+/+), commensalism is (+/0), parasitism is (+/-), and competition is (-/-). Matching each term to its corresponding biological outcome correctly aligns with standard ecological definitions.

Step-by-Step Solution

1
Identify the net effect of the interaction between Rhizobium bacteria and clover.
Both organisms benefit (+/+): bacteria receive sugars while the plant receives usable nitrates.
An interaction where both species benefit is classified as mutualism.
2
Identify the net effect of the interaction between barnacles and the whale.
Barnacles benefit from transport to nutrient flows, while the whale experiences no harm or benefit (+/0).
An interaction where one species benefits and the other remains neutral is classified as commensalism.
3
Identify the net effect of the interaction between mistletoe and the host oak tree.
Mistletoe gains water and minerals while actively weakening the host (+/-).
An interaction where one organism lives on or inside a host and causes harm while extracting nourishment is classified as parasitism.
4
Identify the net effect of two bird species hunting the same rodent prey in an overlapping territory.
Both species face depleted prey availability and increased foraging effort (-/-).
A simultaneous demand by two species for a limited shared ecological resource is classified as interspecific competition.

Key Concept

Symbiotic and Community Interactions in Ecosystems
Estimated Time:1m 0s
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Topics

Ecology and Environment

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