The simplest animals, such as sponges (Porifera) and rotifera (Rotifera), do not require a circulatory system because diffusion allows for the proper exchange of water, nutrients, waste, and dissolved gas. instead, gas, nutrients and waste are exchanged by diffusion.
Does the sponge have a closed circulatory system?
Polyferan is an aquatic animal, also known as a sponge. The sponge does not have a true circulatory system, but a simple stream of water achieves the goal of exchanging nutrients and gas.
Which organism does not have a cardiovascular system?
Flatworms, nematodes, and cnidarians (jellyfish, sea anemones, corals) do not have a circulatory system and therefore no blood. Their body cavities have no lining or liquid in them. They get nutrients and oxygen directly from the water they live in.
Is there evidence of nervous or circulatory system in the sponge?
The field of zoology that studies sponges is known as sponge zoology. Sponges have unspecialized cells that can transform into other types and often move between major cell layers and glial cells in the process. The sponge has no nervous system, digestive system, or circulatory system.
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