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.
This is the story of the birth of life on Earth. Life is old. The dinosaurs are perhaps the most famous extinct creatures, and they had their beginnings 250 million years ago. But life dates back much further. The oldest known fossils are around 3.5 billion years old, 14 times the age of the oldest dinosaurs.