Invertebrate Zoology: Question Bank For Neet

<p>It is estimated that our planet is inhabited by around 1.7 million different organisms. To our surprise every year biologists record about 18000 new species of both plants and animals. Interestingly out of these 18000 species 13500 are novel invertebrates. Biologists have blessed the scientific world with the discovery of 1305250 invertebrates thus far and so many species are yet to be discovered and described.</p><p>These so-called invertebrates are useful in many ways. For instance butterflies beetles bees ants dragonflies snails etc are primary builders of a healthy environment. Similarly the coral reefs add beauty to the oceans with their colorful appearances. </p><p>The Animal Kingdom has categorized just over a million scientifically described species in thirty five phyla. Phylum Arthropoda (insects spiders crustaceans millipedes and centipedes among others) has an estimated 999059 identified species or 85% of the total identified animal species. </p><p>The invertebrates are named so because of the absence of back bone or vertebral column in their bodies. The animals without back bone make therefore a separate group called Invertebrata. At present time there are around thirty invertebrate phyla however we deal with only 9 invertebrate phyla in class 11. Those include phylum Porifera phylum Cnidaria phylum Ctenophora phylum Platyhelminthes phylum Aschelminthes phylum Annelida phylum Arthropoda phylum Mollusca and phylum Echinodermata. </p>