The Wiwaxia external image 200px-Wiwaxia_Smithsonian.JPG

‚ÄčWiwaxia corrugata

Structual Adaptations
Spines on its back- The Wiwaxia had two rows of large spines up its back
to protect it from predators. The spines had roots in the shell of the Wiwaxia
that made up a quarter of their total length.The spines were curved and pointed away from the organisms body. The spines on the front and the back were smaller and gradually got bigger as they got to the middle.

Sclerites- On the exposed areas of the Wiwaxia are hard, flat, overlapping plates. These plates are shaped like ovals and overlap so that the bottom of the plate before overlaps the plate behind it. The amount of plates at different parts of the body make up three different sections. Scientist beleive that Wiwaxia grew when the plates molted together. The plates roots which attach them to the body. There none of these plates on the underside of the Wiwaxia.

Two rows of teeth- The Wiwaxia has two rows of teeth on its jaw. The jaw is located on the bottom surface of the animal. The teeth pointed backwards. When the teeth werent being used they would be folded back into the mouth. When the teeth were being used they would have been sticking out of the mouth making it possible for it to dig for food furthur under the sand on the ocean floor.

external image wiwaxia.gif

Behavioral Adaptation
Bottom Feeder- The Wiwaxia is thought to be a bottom dweller and to feed off the ocean floor. It would have been very protective of itself and wouldnt have done more than just mill about the ocean floors finding things to eat. Scientist dont really know what kind of behavior this animal would have. The only fossils recovered are of the hard plates and the spines on its back. There are no fossils that indicate the activities of a Wiwaxia other than its jaw that has a double row of teeth. Scientists beleive that the presencce of these teeth are and indication that the Wiwaxia fed off the bottom of the ocean.

Physiological Adaptation
Gut- There is not much that scientists know about the anatomy of Wiwaxia. Its beleive that it had a gut that ran from the mouth to the anus in a straight line.

Wiwaxia lived on the bottom of the ocean floor. Fossils have been found in oceans near China, Australia, The Czech Republic, Canada and Russia. They used to live in scattered groups across the ocean floor. They would live in warmer waters where there was a large amount of food available. Their diets consisted of algea and seaweed.

Possible Selection Pressure
The Wiwaxia could have become extinct because of a drop in water temperature. A species of sponge went extinct around the same time due to the cold temperatures 505 million years ago. This may have been the reason for the death of both species.

external image wiwaxia-sketch.jpg

Modern Earthworm
Future Earthworm