Sponges, members of the Porifera, might be the simplest multicellular animals on Earth. They do not have any tissues, organs, or organ systems. In order for sponges to have evolved, what MUST have happened first?
Biology · High School · Tue Nov 03 2020
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the evolution of cells with nuclei and organelles
This is explained by the endosymbiotic theory: Endosymbiosis came about when large cells engulfed small cells. The small cells were not digested by the large cells. Instead, they lived within the large cells and evolved into organelles.on earth in the form of simple bacteria, complex life emerged in the form of large, nucleated cells (eukaryotic cells) with membrane-bound organelles, such as chloroplasts and mitochondria.