As a species humans are acutely aware that other human beings produce waste. This waste and competition for the same resources threatens our individual survival. When biological competition turns a species inward against its own communal organization we get violence as well as cooperation. With cooperative organization we get the concept of economy. The economy is an attempt to control the scarcity of resources by controlling their use and distribution among a population.
People organize to preserve the balance of economies. They form governments, religions, tribes; bodies of authority to control their economy and make sure its resources are used for the good of all of their kind and meeting their community objectives or morality. Our morality is shaped by the scarcity in the environment where they were formed. In the desert water is sacred in flood lands it is a nuisance. These morals are an abstraction of our biological needs and have taken the place of those needs in our value system. To the extent that we as humans would defend them as if they were those biological needs themselves. We are probably the only species that will kill or die in pursuit of an idea: something with no physical substance. This is a side-effect of our tremendous ability to communicate ideas without sharing a first party experience with their creation. Over history a numerous wars have been caused as a result of ideology. But at some point we in our small societies learned to overcome scarcity for a while and improvements in communication have proliferated that learning the world over.
In the pursuit of fair communal exchange of resources in proportion to the effort needed to create or gather them, we developed monetary systems. The development of monetary systems, touted as the root of all evil in religious texts, introduced new "morals" and introduced new competition solely based on the idea of monetary value and its acquisition. This was known as capitalism. People have been equally willing to go to war over it as any prior abstraction of scarcity.