In an field experiment, all the star fishes were removed from an enclosed intertidal area, more than 10 species of invertebrates became extinct within a year, because of

Options

A. Increased intra-specific competition
B. Increased inter-specific competition
C. Decreased inter-specific competition
D. Decreased intra-specific competition

Answer

**Step-by-Step Solution:**

1. **Understanding the Experiment**: The experiment involved the removal of all starfish (Pisaster ochraceus) from an enclosed intertidal area. Starfish are known to be important predators in their ecosystem.

2. **Observing the Effects**: After the removal of the starfish, the researchers observed that more than 10 species of invertebrates became extinct within a year.

3. **Analyzing the Role of Starfish**: Starfish play a crucial role in maintaining the balance of the ecosystem by preying on certain invertebrate species. Their removal leads to an increase in the population of their prey.

4. **Understanding Competition**: With the absence of starfish, the invertebrate species that were previously kept in check by predation began to compete more intensely for resources such as food and space. This situation leads to increased inter-specific competition, where different species compete for the same resources.

5. **Conclusion**: The extinction of more than 10 species of invertebrates can be attributed to increased inter-specific competition due to the absence of starfish. The removal of a key predator disrupted the ecological balance, leading to the decline of various invertebrate species.

6. **Final Answer**: The extinction of more than 10 species of invertebrates within a year is primarily due to increased inter-specific competition resulting from the removal of starfish.

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