Why do We Fear CHange?

What is it about the nature of man that we hold on so tightly to that which is familiar? What is that causes us to fear change, when change is the only thing consistent in this world? You would think, that after a lifetime of change, you would grow used to it. You would learn to embrace it like a long lost loved one. Yet we run from it as if our lives depend on it. 

In fact, the older we get, therefor the more change we have experience, the more we fear it. The more hide from it. I can't help but ponder at this human trait that seems almost to go against survival instincts. For the ability to adapt is critical to survive. If that is so, than again, I ask, why do we fear it so? 

If it is not from inside us, where does this fear come from? How do we fight against it? How do we learn to embrace change? Instead I sit here, on the edge of a massive change in my life, with a feeling of dread that I can not shake. No matter how hard I try to accept it, I can't help but feel lost. As if there is a void that I can never hope to fill. 

I know that once I get to the other side, everything will be fine. Life will go on in the same way it always has. That one change will not alter the fabric of my reality even if it does change the direction, but that doesn't make it any easier to accept. That doesn't take away the feeling of dread that hangs in the air. I know change is important and I should embrace it, but I'm human and that is not our way.