For a basic 500 square feet project in zip code 47474, the benchmark cost to Insulate Your Home ranges between $0.63 - $1.43 per square foot* . To estimate costs for your project: 1.
So in answer to your question, the oldest fossils are stromatolites, and the life forms that created those fossils were prokaryotic bacteria and algae like cyanobacteria.
Fossils of microbe colonies currently are evidence of the first known life on Earth, dating back to 3.5 billion years ago. Thereafter came a long period with little major development. The new analysis aside, fossils of the earliest multicellular organisms had been dated to 565 million to 543 million years ago.