Any physical or genetic defect pales by comparison. That defect of sin condemns us to a life of misery and destruction and an eternity in Hell without salvation in Jesus Christ. By reductionism, finally, there must be some initiation and maintenance of individual life by the soul. Chemicals alone, even complex biochemicals, are inert. A scientist can mix any variety of chemicals and apply any forms of energy, and he will never have life.
Life is more than chemical reactions, even in animals.
Obviously, their spirits differ from those of humans, but they have a spirit of life as well. They are not just biochemicals either. What plants are is less clear. The Bible never says that plants have spirits. In individual humans, there are two traditional views of the origin of the soul.