The term invertebrate refers to an informal collection of a very large number of animals. Inverterbrate means without a backbone. Amongst invertebrates are sponges, flatworms, molluscs, arthropods, insects and various worms. It is estimated that 97% of all species alive today are invertebrates. Insects are by far the most numerous. There are so many species of insects that scientists have yet to discover them all, let alone name or count them. Estimates of the total number of insect fall in the range of 1 to 30 million!
In this quiz, we have chosen 10 invertebrates that live in or around freshwater rivers, streams, lakes and ponds. If you wish to get a closer look at the creatures, just click on the photo to enlarge it.