Category: Invertebrates
These marine invertebrates are known for the dazzling calcified colonies they create as they multiply and grow. Each colony is a collection of genetically identical coral organisms (polyps) that create their own calcium carbonate compartments which accumulate into the large skeletons we associate with coral reefs. Similar in structure to sea anemones, they capture tiny live prey with their tentacles as well as obtaining nutrients from symbiotic alga (zooxanthellae) that live within their tissues. Corals are very sensitive to pollution, blast-fishing, ocean-acidification, temperature change, and other disruptions to their environment.
The world’s first Animals
Invertebrates were the first animals to evolve. While their soft bodies left precious few records behind, there are fossils of sponge-like animals that are 665 million years old, as well as traces of tracks and burros from worm-like animals going back 1 billion years. By comparison, the earliest birds appeared only 150 million years ago! And not only were invertebrates first, they are the most plentiful of animals - it is estimated that 97% of all animals living on the Earth today are invertebrates, with several groups containing more species than all vertebrates combined!
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Discover Animals is a web-based educational resource offered by the NAIA
