What evolutionary advancements do the cnidarians have that are not present in poriferans?

Cnidarians exhibit several evolutionary advancements over poriferans, including the development of true tissues and a simple body plan with distinct cell layers (ectoderm and endoderm). They possess specialized cells called cnidocytes, which contain stinging organelles (nematocysts) used for capturing prey and defense. Additionally, cnidarians have a nerve net that allows for more coordinated movement and responsiveness to environmental stimuli, unlike the more rudimentary cellular organization found in poriferans. These features enable cnidarians to be more active and complex organisms in their ecological roles.