More than 1.5 million species have been recorded in the world .

Answer

### Step-by-Step Text Solution:

1. **Understanding the Definition of a Species**:
- A species is defined as a group of organisms that can interbreed among themselves and produce fertile offspring. If two organisms cannot produce fertile offspring, they are classified as different species.

2. **Current Knowledge of Species**:
- As of now, scientists have identified and described approximately 1.3 million species on Earth.

3. **Dominance of Arthropods**:
- Out of the identified species, around 1.2 million belong to the Arthropoda group, which includes insects, crustaceans, and arachnids.

4. **Estimation of Total Species**:
- It is estimated that there could be around 8.7 million species on Earth, which includes both identified and unidentified species. Many of these undiscovered species are microorganisms, which are challenging to identify due to their minute size.

5. **Conclusion**:
- Therefore, the statement "More than 1.5 million species have been recorded in the world" is accurate, as it encompasses both the identified species and the estimated total number of species.