The meaning of life is a philosophical question that has been asked for thousands of years. It concerns the reason why humans exist and what their significance to this universe is. Of course, this has to do with the belief of being created by a higher being.
I believe that the purpose of life is to survive. We must distinguish ourselves from inorganic matter. The goal is to keep our animal species alive. It's all about competition. When the dinosaurs went extinct, mammals became the dominant species. Like all of nature, when a predator or prey goes extinct, another animal may take it's place. But not always, sometimes, a whole ecosystem may be destroyed or permanently disrupted by the extinction of a few animals.
Edit: The meaning of life is balance. We naturally have to keep in balance with our environment. Which is why it is important to keep the world's bio-diversity alive. If too many animals go extinct, we will not keep balance and more and more animals could go extinct, including humans. Even elements and molecules try to become balanced. The sun constantly emits heat because its elements are trying to become balanced.