Chapter 16, Problem 1SA

Describe three types of symbiotic relationships.

Summary Introduction

To review:

The types of symbiotic relationships.

Introduction:

Symbiosis or symbiotic relationship is a short or long-term biological interaction between different kinds of organisms. It can be obligatory or facultative. In obligatory relationships, one or both the organisms are completely dependent on each other, whereas in facultative symbiosis, the two organisms are partially dependent on each other and can generally live independently also. The organisms interacting in symbiotic relationships are known as symbionts.

Explanation of Solution

Symbiosis is the type of interaction in which the two or more organism are dependent on each other completely or partially and either beneficial or harmful for each other. Symbiotic relationships are of mainly threetypes: mutualism, commensalism, and parasitism.

Mutualism: It is a symbiotic association between the two organisms that are beneficial to each other, it is mostly a long-term association. The symbionts mainly belong to the different species of organisms. For example, the microflora living in the gut of humans are in a mutualistic relationship with the humans. Bacteria synthesize vitamins, which are required by the human host and bacteria takes nourishment from the gut of the humans, therefore, benefiting each other.

Commensalism: It is a relationship between two organisms where one is benefitted by the other, while the other one is neither benefitted nor harmed. For example, many bacteria living on the human skin are neither helpful nor harmful for them, but they derive food and nutrition from the humans thus, are benefiting.

Parasitism: It is a relationship in which one organism is benefitted while the other is harmed. The organism that gets the benefit is known as a parasiteatthe expense of the other organism known as the host. Parasites are of two types, endoparasites that live inside the body of the host, and ectoparasites that live on the body surface of the host.

Conclusion

Therefore, the three main types of symbiotic relationships are mutualism, commensalism, and parasitism that are defined on the basis of their beneficiary or harmful interaction between the organisms involved.