Sea stars are predators that use their tube feet to capture prey. They have a unique digestive system that allows them to evert their stomach out of their mouth and wrap it around their prey. The sea star then secretes digestive enzymes that break down the prey's tissues, and the sea star absorbs the nutrients.
Sea urchins are grazers that use their teeth to scrape algae and other organic matter from rocks and other surfaces. They have a complex digestive system that includes a set of five jaws, a pharynx, an esophagus, a stomach, and an intestine. The sea urchin's teeth are constantly growing, and they are worn down as the sea urchin grazes.
Comparison:
* Both sea stars and sea urchins are echinoderms, but they have different ways of feeding.
* Sea stars are predators that use their tube feet to capture prey, while sea urchins are grazers that use their teeth to scrape algae and other organic matter from rocks and other surfaces.
* Sea stars have a unique digestive system that allows them to evert their stomach out of their mouth and wrap it around their prey, while sea urchins have a complex digestive system that includes a set of five jaws, a pharynx, an esophagus, a stomach, and an intestine.
Contrast:
* Sea stars are predators, while sea urchins are grazers.
* Sea stars have a unique digestive system that allows them to evert their stomach out of their mouth and wrap it around their prey, while sea urchins have a complex digestive system that includes a set of five jaws, a pharynx, an esophagus, a stomach, and an intestine.
* Sea stars have tube feet that they use to capture prey, while sea urchins have teeth that they use to scrape algae and other organic matter from rocks and other surfaces.