Technology has many effects. It has helped develop more advanced economies (including today's global economy) and has allowed the rise of a leisure class. Many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earth's environment. Innovations have always influenced the values of a society and raised new questions of the ethics of technology. Examples include the rise of the notion of efficiency in terms of human productivity, and the challenges of bioethics.