Echinoderms are ocean-dwelling invertebrates in Phylum Echinodermata. They include such animals as sea stars and sand dollars. Echinoderms have a unique water vascular system with tube feet. This allows slow but powerful movement. Chordates include vertebrates and invertebrates that have a notochord. Chordates also have a post-anal tail, dorsal hollow nerve cord, and pharyngeal slits. The term echinoderm means “spiny skin.” An echinoderm's spines aren't actually made of skin. They are part of the animal's endoskeleton and just covered with a thin layer of skin. Most adult echinoderms have... Show more Echinoderms are ocean-dwelling invertebrates in Phylum Echinodermata. They include such animals as sea stars and sand dollars. Echinoderms have a unique water vascular system with tube feet. This allows slow but powerful movement. Chordates include vertebrates and invertebrates that have a notochord. Chordates also have a post-anal tail, dorsal hollow nerve cord, and pharyngeal slits. The term echinoderm means “spiny skin.” An echinoderm's spines aren't actually made of skin. They are part of the animal's endoskeleton and just covered with a thin layer of skin. Most adult echinoderms have radial symmetry. However, echinoderms evolved from an ancestor with bilateral symmetry. You can tell because echinoderm larvae have bilateral symmetry and only develop radial symmetry as adults. Another unique trait of echinoderms is a network of internal canals. Most of the canals have projections called tube feet. The end of each tube foot has a sucker. The suckers can stick to surfaces and help the animal crawl. The suckers can also be used to pry open the shells of prey. Although echinoderms have a well-developed coelom and complete digestive system, they lack a centralized nervous system and do not have a heart. Some echinoderms have simple eyes that can sense light. Like annelids, echinoderms can regrow a missing body part. In fact, a complete starfish can regrow from a single “arm.” Show less
Echinoderms are ocean-dwelling invertebrates in Phylum Echinodermata. They include such animals as sea stars and sand dollars. Echinoderms have a unique water vascular system with tube feet. This allows slow but powerful movement. Chordates include vertebrates and invertebrates that have a notochord. Chordates also have a post-anal tail, dorsal hollow nerve cord, and pharyngeal slits.
The term echinoderm means “spiny skin.” An echinoderm's spines aren't actually made of skin. They are part of the animal's endoskeleton and just covered with a thin layer of skin. Most adult echinoderms have radial symmetry. However, echinoderms evolved from an ancestor with bilateral symmetry. You can tell because echinoderm larvae have bilateral symmetry and only develop radial symmetry as adults. Another unique trait of echinoderms is a network of internal canals. Most of the canals have projections called tube feet. The end of each tube foot has a sucker. The suckers can stick to surfaces and help the animal crawl. The suckers can also be used to pry open the shells of prey. Although echinoderms have a well-developed coelom and complete digestive system, they lack a centralized nervous system and do not have a heart. Some echinoderms have simple eyes that can sense light. Like annelids, echinoderms can regrow a missing body part. In fact, a complete starfish can regrow from a single “arm.”
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