All life on Earth is surprisingly homogeneous from a biochemical point of view. Every organism known to us is primarily built with carbon-based molecules that also contain hydrogen and oxygen, mainly proteins, fats and carbohydrates; short-term energy storage occurs in the phosphate-phosphate bond of ATP, and long-term storage in the carbon-oxygen double bonds (C=O) of complex carbohydrates; information is stored in the sequences of nitrogenous bases of DNA and RNA; chemical exchanges occur through liquid water; of the 92 natural elements, only few others play a role in known biochemistry (sulfur in certain aminoacids, calcium in shells and bones, iron in blood, magnesium in chlorophyll, sodium in nerve cells, etc).
However, would it be possible for organisms that share a common ancestor, however old, to be wildly different? Could completely liquid or completely solid life forms evolve from more traditional ones? Could related organisms use different fundamental forces to control their internal chemical reactions? I know that this is a difficult question to answer, but I guess the bottom line is - can huge changes to biochemistry like this occur without a second genesis, such as the examples I gave above?