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Echinoderms | Groups, Features & Reproduction

Pat Mccaw, Heather Pier
  • Author
    Pat Mccaw

    Pat McCaw MD is a family physician and author. She earned her BS in Biology and MD in Medicine from the University of Iowa in 1998. She subsequently received her MFA in Creative Writing from Hamline University in 2016. She works part-time in family medicine while pursuing her love of writing. She has over 20 years of medical experience with an excellent grasp of the sciences, sociology, behavior, and emotional health. She writes middle grade and young adult fiction, and has experience with professional blog content from GILI Sports. She also maintains her own blog, Pat's Chat, and teaches online classes to educators on inventive ways to use picture books in the classroom to augment their curriculum, and fun exercises to teach creative writing.

  • Instructor
    Heather Pier

    Heather has taught high school and college science courses, and has a master's degree in geography-climatology.

Explore Echinodermata reproduction. Learn the definition of the phylum Echinodermata, find how echinoderms reproduce, and understand how their larvae develop. Updated: 07/23/2022

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Phylum Echinodermata: Overview

The phylum Echinodermata consists of invertebrate marine animals such as starfish, sea urchins, and sea cucumbers. The term echinoderm comes from the Latin roots of ''echino'' for spiny and ''derm'' for skin because the groups of Echinodermata are housed in a hard spiny coat or skin. Echinoderms have been present for over 500 million years, and there are currently 21 classes of Echinoderms that exist with over 6500 extinct species in the fossil record.


The phylum Echinodermata consists of multiple different creatures such as sea cucumbers, sea urchins, and starfish.

Image of the various types of echinoderms.


Echinoderms live mostly in the coral reefs of the Indian and Pacific oceans, but they can be found everywhere but in the Arctic Ocean. The free-floating larval stage during echinoderm reproduction permits the echinoderm species to disperse to all corners of the ocean. They typically display bright colors such as red, orange, greens, and purples.

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  • 0:00 What's an Echinoderm?
  • 0:34 Sexual Reproduction
  • 1:59 Asexual Reproduction
  • 3:19 Echinoderm Larva
  • 4:27 Lesson Summary
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Echinodermata Groups

Echinodermata includes a diverse class of creatures that include:

  • Crinoidea - sea lilies and feather stars
  • Eninoidea - sea urchins
  • Holothuroidea - sea cucumbers
  • Asteroidea - starfish
  • Ophiuroidea - basket, serpent, or brittle stars
  • Concentricycloidea - sea daisies

Sea lilies appear flowerlike with stems, while sea cucumbers appear wormlike and slimy. Sea urchins have spiked armor, and sand dollars are flat and round.

Echinoderms' Features

Echinoderms share common features across all classes. These include:

  • Pentamerous - consists of five equal body parts
  • Symmetrical - a radial symmetry
  • Endoskeleton - an internal skeleton to provide structure
  • Central coelom - a central cavity that consists of a water/vascular structure to operate arms or extensions
  • Regeneration - the ability to regrow body parts

Echinoderms are also benthic, which means they mostly live on the ocean floor. Their diet consists of dead or decaying matter that falls to the seafloor and also preys on small organisms. Sea cucumbers, for example can reach depths of over 10,000 meters.

Echinodermata Reproduction

Depending on the species, echinoderm reproduction might occur sexually or asexually. Sexual reproduction between male and female creatures is the most common method. Asexual reproduction produces a new creature after a body part cleaves off from the main body.

How Do Echinoderms Reproduce Sexually?

How do echinoderms reproduce? Sexual reproduction is most common in echinoderms. During sexual reproduction, the invertebrates do not make physical contact, but the separate male and female sexes fertilize eggs with free-floating sperm within the water. During the sexual reproduction of echinoderms, millions of female eggs are released into the water during spawning. Male sperm then fertilize the eggs when in the same vicinity. Prior to spawning, multiple echinoderms will gather in the same location to increase the likelihood of fertilization.

Sexual reproduction and spawning typically occur annually over a two-month duration, while other species reproduce throughout the year. Certain factors influence sexual reproduction and success during the spawn. These include:

  • Water temperature - warmer waters cause increased echinoderm deaths
  • Light - if the sand is light or dark in color, the echinoderm camouflages its color to improve the chances of success
  • Moon phases - some species reproduce only during certain phases of the moon
  • Water salinity - high or low salt levels impede reproduction

How Do Echinoderms Reproduce Asexually?

How do starfish reproduce? They reproduce through asexual reproduction which involves the fragmentation of a body part followed by the regeneration of that body part. When a piece of the echinoderm cleaves off, it is able to grow again as long as a component of the body or disk remains.

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Frequently Asked Questions

Does echinodermata have separate sexes?

Most species of Echinoderms have separate sexes of males and females. They can reproduce sexually by fertilizing eggs with sperm. Other species are asexual and reproduce through fragmentation and regeneration.

Do echinoderms reproduce asexually?

Echinoderms reproduce asexually by dividing into two or more parts. After the fragmentation, they regenerate new structures. Some Echinoderms also have the ability to reproduce sexually as eggs and sperm are released into the water to be fertilized.

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