Darwinian Evolution is popularly seen as a relentless and continuous struggle between individuals and between species. Competing for scarce resources, at the expense of others, is regarded as the eternal struggle to survive and replicate; is in that view singlehandedly driving evolution itself.
The success of many a species to survive and replicate though is highly dependent on the collaboration of individuals. Collaboration by individuals, like forming groups, of the same species increases the odds of survival and successful replication, if not for the individual then for the group it belongs to and hence the groups offspring.
Reproduction is one of the purposes to collaborate between individual organisms of a specie. In an environment where individual organisms are competing for scarce resources collaboration of individual organisms can enhance the odds of survival for the reproductive individual and their offspring and hence for the species.
Collaboration is therefore an evolutionary strategy that allows the individual and the group to better compete for scarce resources, hence for its survival and reproduction.
In an evolutionary sense our species, the Homo Sapiens, is part of a branch of the homo species in which the individuals live in groups to secure reproduction, survival of self and offspring and enhance their comfort of living. Homo Sapiens does not distinguishes itself from other homo’s, like Habilis or Erctus for the fact that its individuals collaborate for these purposes but in the shear extent of it.(Nb Nor can it be distinguished by tool making as the austalopithus may have been making tools earlier then homo’s. For a concise overview of the origins of humans: “Here’s Everything Science Knows So Far About The Origins of Humans” by Wood and Westaway via Science Alert)
That said, we see collaboration between species as well: symbiosis. An “individual” human body consists of many species living in symbiosis. Take for instance your intestinal flora, of roughly 2 kg’s of bacteria, that is helping you to digest the very food you eat.
Evolution can only be understood correctly if we consider, next to “competition”, “symbiosis” and “collaboration” as principal and equally important drivers of evolution.