Alien Anomalies

Althouth The watcher pointed out that this could be a biggie, I still do not think people realise what this means. It means that we do not need phosperous to carry out some of the basic processes of life. Arsenic will do just as well. And if we can replace Phosphorus with Arsenic, maybe we can soon replace Carbon with Silica too?

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.


It also means that life can exist in environments very 'different' to ours. 
One 'essential' element down, five to go...

Stanford University
On Orbit
Spaceref
Washington Post
Universe Today