Sponges lack a signaling pathway that responds to low intracellular oxygen levels in more complex animals. Do they use a different mechanism for this purpose or did their earliest ancestors evolve at a time when less oxygen was available?
Sponges lack a signaling pathway that responds to low intracellular oxygen levels in more complex animals. Do they use a different mechanism for this purpose or did their earliest ancestors evolve at a time when less oxygen was available?