there is something special or unique or not entirely understood about biological life (at least human life if not all life with a central nervous system) that produces sentience/consciousness/Qualia ('soul'-ism as you might put it, but no 'soul' is required for this conclusion, it could just as easily be termed 'mystery-ism' or 'unknown-ism')
This is just wrong lol, there's nothing magical about vertebrates in comparison to unicellular organisms. Maybe the depth of our emotions might be bigger, but obviously a paramecium also feels fear and happiness and anticipation, because these are necessary for it to eat and reproduce, it wouldn't do these things if they didn't feel good
The discrete dividing line is life and non-life (don't @ me about viruses)