Wikipedia has a great summary of what sustainable design really is. The statement "Sustainable architects design with sustainable living in mind" is very true, and very important! It brings attention to the fact that if the people living in the sustainable building don't make a commitment to live with sustainability in mind, they are not doing their part. For instance, designing your home with sustainability in mind is a great move in the right direction, but if you still buy toxic cleaning chemicals and use them on a regular basis, you are still doing damage. It's important to think of how we use our sustainable homes, office buildings, parks, etc. that is even more important than choosing a sustainable design.
Furthermore, this Wikipedia definition includes a good definition of what morphogenetic design is: "This design practice emphasizes efficiency of heating and cooling systems, alternative energy sources such as passive solar, appropriate building siting, reused or recycled building materials, on-site power generation (solar technology, ground source heat pumps, wind power), rainwater harvesting for gardening and washing, and on-site waste management such as green roofs that filter and control stormwater runoff."
By reducing the amount of energy needed to heat and cool a building, and the amount of energy that goes into building it (including how far the materials are shipped to the building site), the design becomes efficient, and reduces the cost to run and maintain it.