Plagiarism is terrible, every time. We should never use an idea and claim it as our own. But engineers, makers, and architects are often told to study others' work to get inspired for your own design. It can be as simple as asking the person next to you to designing the David L Lawrence Convention Center off of the Pittsburgh Bridges.
But if we are counting how much research and development all of humanity has done, it pales in comparison to the millennia to experimentation that life overall has had. This idea of mimicking life and our greater ecosystems, or biomimicry, is best explained by Vox and 99% Invisible below.