You are here: Home / Archives for Echinoderm

Getting to know three … Echinoderm edition

August 3, 2012 by Leave a Comment

Sure you know that some animals are related to one another. Often though it’s difficult to pinpoint their similarities.  Well, on the third day of every month I am going to explain three features that are common among the animals of a certain group. Each group generally has more than three representatives, but I am going to choose three to keep it simplified.

To get us started … Have you ever thought about what a sea urchin, sea star, and a sand dollar have in common? Among others in this group those three animals are in a phylum of marine animals know as the echinoderms. Sea cucumbers and brittle stars are also well-known echinoderms. Check out the image below to learn what these animals all have in common.

Please do not hesitate to email me at info@beachchairscientist.com with questions, comments, or suggestions.

Filed Under: Echinoderms Tagged With: , , , , ,

How does a sea star move?

May 29, 2012 by 1 Comment

I came across this image of a dissected sea star and had to share it. It does a great job of identifying intricate details of the sea star physiology that are involved with the locomotion and vascular system of the invertebrate.

The vascular system is part of the circulatory system that helps  transport nutrients back and forth across the animal’s body. These echinoderms (a group of marine invertebrates known for bumpy skin and radial symmetry, including sea stars, sea urchins, and sand dollars) begin the movement of their tubed feet with water entering through the madreporite. The madreporite is the wart-like, red or yellow opening in the center of the sea star. It acts like a  pressure-equalizing valve. Next, the water will circle around the stone canal to be distributed to the arms of the sea star. At this point, water goes to the tubed feet and being the act of moving by contracting and stretching. Tubed feet also come in handy when grasping food to place into the mouth of the sea star. For more information and a great image of the madreporite of a sea star click here.

If you have a great question just email info@beachchairscientist.com.

Image (c): top – http://w3.shorecrest.org, bottom – wikipedia.com

Filed Under: Echinoderms Tagged With: , , , , , , , ,

What eats sea urchins? Revisited

January 2, 2012 by 1 Comment

Sea UrchinBack in 2008 we brought you some information on what eats sea urchins. After all, it is hard to imagine anything being able to enjoy the spiny echinoderms. Here is an interactive game (you must have Flash) produced by Stanford University that takes it one step further. Try to place which animals and/or plants are eaten by the sea urchin (prey), which animals eat the sea urchin (predator), and which animals and/or plants may not have a relationship with the sea urchin. You see some great similarities of the animals that eat the sea urchin! Come back here and share what you discover after playing the game. Enjoy!

Related articles
Filed Under: Echinoderms Tagged With: , , ,

How do sea stars eat?

November 18, 2008 by 4 Comments

StarfishFirst, sea stars grip their prey (e.g., bivalves, such as clams and oysters) with their suction feet and pry them apart to eat the muscle inside the shells. Then, once the bivalve’s shell is open, the stomach of the sea star emerges from the middle of the underside of its star-shaped body to absorb the delicious entrée inside itself. After this happens, the animal is full and not going anywhere soon (e.g., me after Thanksgiving dinner).

A sea star is another common name for starfish. Scientists, and the likes of me, are on a campaign to get people to refer to this echinoderm as the ‘sea star’ instead of a starfish. Since, well, they simply are not fish. Similarly, jellies are not called jellyfish anymore.

Check out this video from the Monterey Bay Aquarium of a sea star chowing down!

Do you have another great question? Email info@beachchairscientist.com and share your thoughts.

Filed Under: Echinoderms Tagged With: , , , ,