Techno,
Science can say very little about events that happened millions of years. Also, the dynamic, sometimes changing, environment that a life form is born into adds complexity and uncertainty to any scenario. Looking at it without precision means a small error in interpretation may associate itself and increase as attempts are made to explain this or that change in the organism over time.
Imagine using a rifle that can hit a target one mile away. The user has many factors to take into account. Without sufficient knowledge, it is likely the target will not be hit or another, unintended target is hit. Wind speed, the drop in height in a given caliber of bullet as it travels to the target and so on. Living things are far more complex and yes, they must be able to survive in their environment.