Category: Invertebrates
These water dwelling, carnivorous animals are named for a type of flower, no doubt owing to their often colorful flower-like appearances and generally stationary lifestyle. They attach to the substrate with an adhesive foot called their “basal disc,” above which is their body column topped by an “oral disc” surrounded by stinging tentacles. Their diet consists mainly of small fish, shrimp, and other tiny aquatic organisms. With a few highly toxic exceptions, most anemones are harmless to humans. Many sea anemones form a facultative symbiotic relationship with certain single-celled algae species, benefitting from the byproducts of the alga’s photosynthetic processes.
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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