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.
Stromatolites are among the world's oldest fossils, some of which are over 3.5 billion years old. Stromatolites are structures formed by huge colonies of cyanobacteria, formerly called blue green algae, which contributed directly to the formation of the Earth's atmosphere and its currently habitable state.tromatolites are formed by prokaryotic cyanobacteria, which have cells lacking a distinct nucleus. Prokaryotic bacteria are considered by some scientists to be the oldest and most primitive life form on Earth, with a well established fossil record stretching back for millions of years.