Photosynthesis, for example, is a way that plants take energy from the abiotic environment and incorporate it into the biotic environment by synthesizing sugars and proteins from it. Other components of the biotic environment, such as herbivores, eat the plants and transfer the nutrients further along the chain.
Source: Adaptec. Backplanes are the fundamental building block to any storage appliance that is meant to support hot plugging. So, SAS expanders will always go hand in hand with powerful backplanes (whether these are in a single box or not).
A split backplane is often used to handle a large number of signals. Split backplane configurations will divide bus connections between two motherboards (one on either side of the daughterboards). Using two motherboards shortens the path of connections to daughterboards and often improves performance. See backplane for more information.