Are sponges animals or plants?
Despite looking like a plant growing from the ocean floor, sea sponges do not photosynthesise, but rather consume organic matter from the ocean around them, which makes them an animal. Sponges are classified into three species based on their skeleton, whether its made from glass (silicon), calcium carbonate or organic matter. In the Research School of Earth Sciences, research is focused specifically on silicon skeleton sponges that can be found in fresh or saltwater at any depth, anywhere in the world. How long have these multi-cellular organisms been around? Sponges evolved somewhere between 540 and 600 million years ago, and that’s just the ones we know about. “One of the difficult aspects with dating these organisms is that is you can only date the ones that leave fossil skeletons,” Ellwood says. “And plenty of species, particularly the organic ones, don’t leave a fossil record so we don’t know for sure if they were there.” Here in Australia we have existing species dating back more
