Which scenario describes a relationship of parasitism?
A. Oxpecker birds eat parasitic ticks off the backs of zebras
B. A polar bear catches a seal for dinner
C. Birds feed off the insects that are stirred up from the grasses as cattle move through
D. Birds feed off the insects that are stirred up from the grasses as cattle move through
The Correct Answer and Explanation is :
The scenario that describes a relationship of parasitism is B. A polar bear catches a seal for dinner.
However, while “B” involves a predator-prey interaction, none of the options actually depict parasitism. Let me clarify why none of the options fit parasitism and what parasitism truly is.
Definition of Parasitism:
Parasitism is a relationship between two organisms where one organism (the parasite) benefits at the expense of the other (the host), often causing harm but typically not immediate death to the host. The parasite relies on the host for resources such as food, shelter, or reproduction, while the host suffers negative consequences as a result.
Explanation of Each Scenario:
- A. Oxpecker birds eat parasitic ticks off the backs of zebras:
This is a mutualistic relationship. The oxpecker benefits by gaining food (ticks), while the zebra benefits because the ticks, which can cause irritation or transmit diseases, are removed. - B. A polar bear catches a seal for dinner:
This describes predation, not parasitism. Predation involves one organism (the predator) killing and consuming another organism (the prey). Unlike parasitism, predation results in the immediate death of the prey. - C and D. Birds feed off the insects stirred up from the grasses as cattle move through:
Both of these scenarios describe commensalism, a relationship in which one organism benefits while the other is neither helped nor harmed. The birds benefit from the easy access to food, while the cattle are unaffected.
Correct Example of Parasitism:
A correct example of parasitism would be a tapeworm in the intestine of a human or animal. The tapeworm absorbs nutrients from the host, depriving the host of essential nutrients and potentially causing malnutrition, while the host remains alive for the parasite to continue feeding.