Title: 9 Major Groups of Invertebrate Animals - Owlcation
Headings: 9 Major Groups of Invertebrate Animals
9 Major Groups of Invertebrate Animals
What Are Invertebrates?
Photos of Some Common Invertebrates
The 9 Main Phyla of Invertebrates
1. Phylum Porifera (Sponges)
2. Phylum Cnidaria (Coelenterates)
Examples of Cnidarians (Coelenterates)
3. Phylum Platyhelminthes (Flatworms)
Examples of Platyhelminthes (Flatworms)
4. Phylum Echinodermata (Echinoderms)
Examples of Echinodermata (Echinoderms)
5. Phylum Mollusca (Mollusks)
Examples of Mollusca (Mollusks)
6. Phylum Nematoda (Nematodes)
Examples of Nematoda (Nematodes)
7. Phylum Arthropoda (Arthropods)
8. Phylum Annelida (Annelids)
Examples of Annelida (Annelids)
9. Phylum Chordata (Chordates)
Examples of Invertebrate Chordates
References
Other Science Articles
Questions & Answers
Comments

Content: Mathilda Khoo via Unsplash
What Are Invertebrates? In contrast to bony vertebrates, invertebrates are animals with no vertebral column or backbone. Invertebrates comprise approximately 97% of the animal kingdom. Most of them are soft-bodied and do not develop rigid internal skeletons. Many invertebrates do, however, possess hard exoskeletons to protect their bodies from their environments. Some common examples of invertebrates are snails, sponges, earthworms, squids, sea-stars, centipedes, butterflies, spiders, and jellyfish. Photos of Some Common Invertebrates
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Unidentified crab from Pexels
Pexels
Unidentified grasshopper from Pixabay
Pixabay
Unidentified butterfly from Pexels
Pexels
Unidentified wasp from Pexels
Pexels
Unidentified jellyfish from Pexels
Pexels
Unidentified inchworm from Pexels
Pexels
Unidentified starfish from Pexels
Pixabay
Unidentified anemone from Pexels
Pexels
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The 9 Main Phyla of Invertebrates
Groups of Invertebrate Animals
Examples
Estimated Number of Species
Phylum Porifera
Sponges
3,000
Phylum Cnidarians
Jellyfish, corals, anemones, hydra
9,200
Phylum Platyhelminthes
Flatworms, flukes, tapeworms
15,000
Phylum Echinodermata
Sea stars, brittle stars, sea urchins, sea cucumbers
5,000
Phylum Mollusca
Snails, clams, squids, octopi, other mollusks
70,000
Phylum Nematoda
Ascaris, vinegar eels, hookworms, nematodes, pinworms
500,000
Phylum Arthropoda
Crabs, scorpions, insects, spiders, millipedes, centipedes, barnacles
750,000
Phylum Annelida
Earthworms, leeches, lugworms
22,000
Phylum Chordata
Sea squirts, lancelets
2,000
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Polymastia boletiformis
Bernard Picton, B165841, CC BY-SA 4.0
Unidentified Porifera photo from Wikipedia
Albert Kok at Dutch Wikipedia, Spons, marked as public domain, more details on Wikimedia Commons
Clathrina clathrus
The original uploader was Elapied at French Wikipedia., Clathrina clathrus, CC BY-SA 2.0 FR
A variety of Porifera
Van Soest R, Boury-Esnault N, Vacelet J, Dohrmann M, Erpenbeck D, De Voogd N, Santodomingo N, Vanhoo
Unidentified Porifera photo from Wikipedia
Johnmartindavies, A colourful Sponge on the Fathom, CC BY-SA 3.0
"Pipe organ" sponges
icelight, Purple Cup Sponges, CC BY 2.0
Unidentified Porifera photo from Wikipedia
matthew lee, Layang-Layang diving47, CC BY 2.0
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1. Phylum Porifera (Sponges)
Sponges, or phylum Porifera, are one of the most common types of invertebrate animals. Currently, there are about 3,000 documented sponge species.