The Urmetazoan is the hypothetical last common ancestor of all animals. The name derives from metazoa, an old biological term for animals. It is universally accepted to have been a multicellular heterotroph — with the novelties of a germline and oogamy, an extracellular matrix (ECM) and basement membrane, cell-cell and cell-ECM adhesions and signaling pathways, collagen IV and fibrillar collagen, different cell types (as well as expanded gene and protein families), spatial regulation and a complex developmental plan, and relegated unicellular stages.
The Urmetazoan is the hypothetical last common ancestor of all animals. The name derives from metazoa, an old biological term for animals. It is universally accepted to have been a multicellular heterotroph — with the novelties of a germline and oogamy, an extracellular matrix (ECM) and basement membrane, cell-cell and cell-ECM adhesions and signaling pathways, collagen IV and fibrillar collagen, different cell types (as well as expanded gene and protein families), spatial regulation and a complex developmental plan, and relegated unicellular stages.
==Choanoflagellates== All animals are posited to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates whose cell morphology is similar to the choanocyte cells of certain sponges.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).