Differences between Mutualism and Commensalism: Types & Facts

Introduction to Symbiotic Relationship

Symbiosis is the relationship between organisms of different species that show an intimate association with each other, usually concerning existence, development, and or reproduction. Symbiotic relationships provide at least one of the participating species with a nutritional advantage. The three types of symbiosis have been recognised depending on the nature of the relationship: parasitism, commensalism and mutualism. While parasitism and commensalism are generally considered non-reciprocal, and one species benefits at the other’s expense, mutualism is always reciprocal.

Mutualism and commensalism can be considered to be significant in ecology. Mutualism explains linkings between two organisms, whereby each enjoys improved fitness as a result of cooperation. However, commensalism refers to situations where one organism benefits, but the other is not influenced by the interaction.

What is Mutualism?

Mutualism is a kind of symbiotic relationship whereby there is the sharing of benefits between two species of organism. While this interaction is beneficial for the two partners, it increases the fitness, survival, or reproduction rate for both species. Mutualism is always reciprocal.

Examples of Mutualism Pollination, Mycorrhizae, Cleaning Symbiosis)

Mutualism is pervasive and can be observed across various ecosystems:

Pollination: It is mutualism in which bees benefit by getting their food and at the same time assisting the plant in pollination since the insect has brought pollen to the plant.

Mycorrhizal Associations: Mycorrhizal fungi are microbes that form beneficial associations with plants by penetrating plant root structures and in the process enhancing the plant’s ability to obtain nutrients from the soil in return for carbohydrates derived from plant photosynthesis.

Cleaning Symbiosis: For example, the cleaner fish like cleaner wrasses feed on the remains and feed on the parasites that may be present on the larger fish since they manage to feed on the fish as it is cleaning.

Types of Mutualism (Obligate, Facultative, Defensive, Trophic)

Mutualistic relationships can be categorized based on the nature of the benefits exchanged:

What is Commensalism?

Commensalism is one of the types of symbiotic relationships in which one of the organisms benefits while the other remains unaffected. As for commensal relationships, one participant receives profit in the form of shelter, food, or transportation, whereas the other participant is not affected at all.

Examples of Commensalism (Epiphytes, Remoras, Birds nesting)

Commensalism is prevalent in various ecosystems:

Epiphytic Plants: Some plants like the orchids and the ferns cling to the existing trees on which they get support and light without harming the trees. Orchids can be found growing on tree branches and trunks. They extract fluids from tree stems but do no assistance to the host. The only source of water for orchids is their hosts. Since they are able to prepare food for themselves, they do not need nutrients from trees.

Remoras and Sharks: This is because remoras use their clamp-like mouth that is found at the top of their head and attach themself to sharks, feeding on the leftover scraps of meat, without negatively affecting the shark.

Birds and Nesting: Birds create their nests in trees. They build their nests on the branches or in tree hollows and this does not harm the tree because it does not interfere with the tree's ability to live.

Types of Commensalism (Inquilinism, Phoresy, Microbiota)

Commensal relationships can be categorized based on the nature of benefits received:

Key Differences Between Mutualism and Commensalism

The mutualism and commensalism differences are given below.

Ecological Significance of Mutualism and Commensalism

Knowledge of these relations can go far in contributing to knowing the processes that take place in ecosystems in terms of species complexity and sustainability. Mutualism and commensalism show how organisms interact or reciprocate with each other in a certain environment that improve nutrient cycling, resource availability, and survival chances. Such interactions maintain ecological balance, promote coexistence of species, and contribute to the overall health of ecosystems.

Mutualism vs Commensalism NEET MCQs (With Answers & Explanations)

This topic carries a significant weightage in NEET exam. Following topics are important while preparing for the exam:

• Mutualism and its types with examples

• Mutualism (Mycorrhizae and nitrogen-fixing bacteria in legumes)

• Commensalism and its types with examples

• Factors Influencing Interactions

Practice Questions for NEET

Q1. Epiphytes that are growing on a mango branch are an example of which of the following?

1. Amensalism

2. Commensalism

3. Mutualism

4. Predation

Correct answer: 2) Commensalism

Explanation:

Epiphytes are plants that grow on the surface of other plants, such as mango trees, for physical support. They do not enter into the host tissues or withdraw water and nutrients from the host plant. They obtain moisture and nutrients from the air, rain, or debris around them. Such a relationship is an example of commensalism, a symbiotic relationship where one organism is affected, but the other one is not.

Hence, the correct answer is option 2) Commensalism.

Q2. Mycorrhizae are the example of :

1. Fungistasis

2. Ammensalism

3. Antibiosis

4. Mutualism

Correct answer: 4) Mutualism

Explanation:

Mutualism -

This interaction confers benefits on both the interacting species. Lichens represent an intimate mutualistic relationship between the fungus and photosynthesising algae or cyanobacteria. Similarly, the mycorrhizae are associations between fungi and the roots of the higher plants. The fungi help the plants in the absorption of essential nutrients from the soil while the plant, in turn, provides the fungi with energy-yielding carbohydrates.

Hence, the correct answer is option 4) Mutualism.

Q3. Predation, parasitism, and commensalism have the following things in common:

1. The interacting species coexist close together.

2. The interacting species suffer.

3. One of the interacting species gains.

4. One of the interacting species maintains its neutrality.

Correct answer: 1) The interacting species coexist close together

Explanation:

The interdependent species that engage in predation, parasitism, and commensalism coexist near one another.

The fact that interacting species coexist nearby is a frequent characteristic of predation, parasitism, and commensalism. Commensalism is a kind of interaction where one species benefits and the other is left unaffected.
The epiphyte benefits, while the host is unaffected. The two species continue to interact and associate closely with one another. Predation is a harmful relationship in which the predator gains an advantage over the prey. The two species continue to interact and associate closely with one another. The host is injured and the parasite benefits from parasitism, which is a negative relationship. The two species continue to interact and associate closely with one another.

Hence, the correct answer is option 1) The interacting species coexist close together.

Also Read:

• Practice MCQ on Mutualism

• Practice MCQ on Commensalism

• Population Interaction

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