Complex sentence: From an evolutionary perspective, Herbert Spencer, a psychological egoist, argued humans and animals primarily sought to survive and protect their lineage, and the need for the individual and for the individual's immediate kin group to live superseded the other's need to live.
Split into simpler sentences: From an evolutionary perspective, Herbert Spencer, a psychological egoist, argued humans and animals primarily sought to survive and protect their lineage. Essentially, the need for the individual and for the individual's immediate kin group to live superseded the other's need to live.