A sponge is the simplest multi-celled animal.  It's really just a colony of single celled animals, all the same.  Scientists studying sponges once put a live sponge in a blender, chopped it to tiny pieces, than dumped the pieces back into water.  They were surprised to find that the sponge reassembled itself just as it was before.
The fact that the sponge reassembled was strange enough, but why as it was before?  It could have reassembled in a different shape.  It could have reassembled as several smaller sponges.  But it reassembled just as it was before.

Alfred Russel Wallace would have understood.  He is the scientist who worked with Darwin on the theory of evolution (Darwin remember was a reporter).  Wallace believed that something had to be guiding evolution.  There had to be a kind of mold for it to follow.  He believed that mold, that guide was spirit.  Darwin left that part out because he thought saying anything about spirit would have made his findings sound unscientific.