* Sponges (Porifera) are the simplest multicellular animals. They lack true tissues and organs, and their body structure is very basic. They are considered the most ancient lineage of animals.

* Chordates are a phylum that includes vertebrates, but also includes simpler animals like tunicates and cephalochordates. Chordates evolved later than sponges.

* Vertebrates are a subphylum within the Chordates. They are distinguished by having a backbone. They evolved after chordates.

* Deuterostomes are a large group of animals that includes chordates and echinoderms. They are characterized by a specific embryonic development pattern. While deuterostomes evolved before vertebrates, they still came after sponges.

Therefore, sponges represent the earliest lineage of animals.