The struggle for existence among living organisms today is a result of sin entering a perfect creation and is not the method of bringing that creation into existence. Nature is in turmoil. Organisms do struggle for survival. Competition is often fierce. While there are many examples of cooperation in nature, it can always be explained in terms of selfish gain and cooperation is the easiest way to obtain the desired end.
Organisms do act selfishly.
Some Christians debate the effects of the fall and how far back into earth history the effects can be realized. But the point is that something happened at the fall. This passage makes clear that the creation does not function today as God intended it to and it is not the creation's fault. The creation was subjected to futility because of man's sin. When we take the time to investigate whether the God revealed in the Scriptures is the same God who created through the evolutionary process as it is currently understood, the answer is clear.