'Barnacles' growing on the back of a whale is a classical example of:
Commensalism
Understanding Ecological Relationships
Ecological relationships describe the interactions between different species living in the same environment. These interactions can be beneficial, harmful, or neutral to the species involved. The question asks about the relationship between barnacles and whales, which is a classic example of a specific type of ecological interaction.
Analyzing the Barnacle-Whale Relationship
Let's consider how barnacles growing on the back of a whale affects both organisms:
- Barnacles: Barnacles are filter feeders that need a hard surface to attach to. By attaching to a whale's back, they gain a stable place to live, access to nutrient-rich water as the whale swims, and protection from predators that might target them if they were stationary on rocks. The barnacles clearly benefit from this relationship.
- Whale: For the most part, the whale is not significantly affected by the barnacles. While a very large number of barnacles might cause some minor irritation or drag, in typical situations, the whale neither benefits nor is harmed. Their presence is generally considered neutral to the whale.
Based on this analysis, we have a relationship where one species (the barnacle) benefits, and the other species (the whale) is neither significantly harmed nor helped (is neutral).
Exploring Types of Ecological Interactions
Let's look at the options provided and how they compare to the barnacle-whale interaction:
| Interaction Type | Effect on Species 1 | Effect on Species 2 | Description | Example |
|---|---|---|---|---|
| Mutualism | Benefited (+) | Benefited (+) | Both species benefit from the interaction. | Bees and flowers (bee gets nectar, flower gets pollinated) |
| Predation | Benefited (+) | Harmed (-) | One species (predator) hunts and kills the other (prey). | Lion and zebra |
| Ammensalism | Unaffected (0) | Harmed (-) | One species is harmed, and the other is unaffected. | Mold producing penicillin (harms bacteria, mold is unaffected) |
| Commensalism | Benefited (+) | Unaffected (0) | One species benefits, and the other is neither harmed nor helped. | Barnacles on whales, Egret birds following cattle (egrets eat insects disturbed by cattle, cattle are unaffected) |
Identifying Commensalism
Comparing the barnacle-whale relationship (barnacle benefits, whale is unaffected) with the definitions above, it perfectly matches the description of Commensalism.
Therefore, 'Barnacles' growing on the back of a whale is a classical example of Commensalism.
Revision Table: Key Ecological Terms
| Term | Meaning | Example |
|---|---|---|
| Mutualism | Both species benefit. | Clownfish and sea anemones. |
| Predation | One species hunts and kills another. | Wolf and deer. |
| Ammensalism | One is harmed, one is unaffected. | Certain plants releasing chemicals that inhibit other plants. |
| Commensalism | One benefits, one is unaffected. | Barnacles on whales. |
| Parasitism | One benefits (parasite), one is harmed (host). | Ticks on a dog. |
Additional Information on Commensalism Examples
Commensalism is a common interaction in nature. Besides barnacles on whales, other examples include:
- Epiphytic plants (like orchids or bromeliads) growing on trees. The epiphytes get support and access to sunlight, while the tree is usually unaffected.
- Remora fish attaching to sharks. Remoras get transportation, protection, and scraps of food, while the shark is generally not affected.
- Cattle egrets feeding on insects stirred up by grazing livestock. The egrets get food, and the livestock are unaffected.
These examples further illustrate the $+ / 0$ nature of the commensal relationship.
Important Questions from Organisms and Environment
Some of the fresh water fishes commonly found in India are: (A) Hilsa (B) Pomfrets (C) Catla (D) Rohu (E) Common carp
Which of the following does not show parthenogenesis?
The interaction between two species where one species benefits and the other is neither benefitted nor harmed is known as:
In a laboratory population of 80 fruit flies, 8 died in a week. What is the death rate of fruit flies?
Identify the mammals which live wholly in water:
A. Dolphins
B. Seals
C. Sea Horse
D. Sea Cow
Choose the correct answer from the options given below:
