* Vastness and Diversity: The invertebrate world is incredibly vast and diverse. New species are constantly being discovered, and many remain unidentified.
* Difficult to Count: Many invertebrates are tiny and live in hidden environments. It's impossible to count every single one.
* Population Fluctuations: Invertebrate populations fluctuate naturally, making an exact number fleeting.
Instead of an exact number, here are some relevant facts:
* Over 95% of all animal species are invertebrates: This makes them the dominant animal group on Earth.
* Millions of known species: Scientists have described millions of invertebrate species, and new ones are discovered regularly.
* Estimated total: Some estimates suggest there may be tens of millions or even hundreds of millions of invertebrate species.
While we can't know the exact number, it's safe to say that invertebrates vastly outnumber vertebrates and play critical roles in ecosystems worldwide.