3 points S While some scientists studying sponges suggest

Last updated: 6/17/2023

3 points S While some scientists studying sponges suggest that sponge larval hair cells are proto neurons because they express some genes which are expressed in neurons others reject this hypothesis which sugg that cnetophores comb jellies are ancestral to all animals Cnetophores do have a nervous system Two hypothesis could explain the presence of the nervous system in cnetophores and the lack of one sponges Either 1 the common ancestor of all living animals was a cnetophore and it was subsequently lost in sponges OR 2 O the nervous system evolved in cnetophores separately convergence from the nervous system which is common and ancestral for all other animals O the lack of a nervous system was inherited by all animals from sponges O animals evolved into sponges which subsequently evolved into cnetophores O while sponges and cnetophores lost their nervous system animals gained it independently