We have a lot to learn from nature when it comes to living more sustainably. There is no need to reinvent the wheel when we can look at the world around us and copy what we know is already working. For example, spiders will let water droplets form on their web for their source of water. Instead of needing it to rain to capture and reuse rainwater, we can create a system that allows dew drops from the moisture of the air to form and slide down into a basin with the help of gravity to capture water for the buildings use. These basins can of course also capture rain water but this method will especially be helpful in areas that do not get much rainfall and want to limit the external water use of their building. All buildings should have also have rain capture systems that recycle and reuse the water.
Another sustainable approach we can use from nature is constructing part of the building to be underground so that the temperature in that area is regulated at a relatively constant and comfortable temperature. The air can then be naturally pulled into the other parts of the building by having windows that automatically open and close to move the air around the building. Many animals live underground so that they are always in a comfortable temperature, especially during seasons with harsher climates and the same can be done to regulate building temperatures.
Another part of nature we can copy is the way sunflowers turn to always face the sun so that they can maximize the amount of sunlight they get in a day. This same idea can be applied if we had the technology to move solar panels to get the most irradiance throughout the day. The same can go for parts of the building which are used as thermal masses so that they retain as much heat as possible by staying in the suns rays rather than possibly being shadowed by another part of the building. Lastly, when it comes to skylights that have a sun tunnel system, if these pieces could move to let in the most sunlight possible they can better light up a space rather than only being the brightest when the sun comes in at a certain angle.