Which of the following is not an example of commensalism ?

Options

A. Orchid on mango branch
B. Cuckoo and crow
C. Egret and grazing cattle
D. Sea anemone and clown fish

Answer

To solve the question "Which of the following is not an example of commensalism?", we will follow these steps:

### Step 1: Understand Commensalism
Commensalism is a type of symbiotic relationship between two organisms where one organism benefits and the other is neither helped nor harmed.

**Hint:** Remember that in commensalism, one organism gains benefits while the other remains unaffected.

### Step 2: Analyze the Options
We will analyze each of the provided options to determine if they represent commensalism or not.

1. **Orchid on Mango Branch**: This is an example of commensalism. The orchid benefits by getting a place to grow, while the mango tree is neither harmed nor benefited.

**Hint:** Think about how epiphytes (like orchids) grow on other plants without harming them.

2. **Cuckoo and Crow**: This is not an example of commensalism; it represents brood parasitism. The cuckoo lays its eggs in the crow's nest, relying on the crow to raise its young.

**Hint:** Consider how brood parasitism involves one organism benefiting at the expense of another.

3. **Egret and Grazing Cattle**: This is an example of commensalism. The egret benefits by eating ticks off the cattle, while the cattle are not harmed or benefited by the presence of the egret.

**Hint:** Think about how some birds benefit from the presence of large herbivores without affecting them.

4. **Sea Anemone and Clownfish**: This is also an example of commensalism. The clownfish gets protection from the sea anemone, while the anemone is not harmed.

**Hint:** Remember how clownfish live among the tentacles of sea anemones without causing them harm.

### Step 3: Identify the Correct Answer
After analyzing all the options, we find that the **Cuckoo and Crow** is the correct answer, as it is not an example of commensalism but rather an example of brood parasitism.

**Final Answer:** Cuckoo and Crow