Marine life from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. Microorganisms constitute more than 90% of the marine biomass. A microorganism (or microbe) is a microscopic living organism, which may be single-celled or multicellular. Microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some species of fungi, algae, and certain microscopic animals, such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify viruses (and viroids) as microorganisms, but others consider these as nonliving. In
The Spiral of Life Mural Series The Spiral of Life Mural Series The Spiral of Life mural series is a collection of phylogenetic tree public art murals currently housed by the Pittsburgh Zoo & PPG Aquarium, the National Aviary and the Carnegie Science Center. The murals reinterpret Charles Darwin's Tree of Life model appearing in "On the Origin of Species" by using the spiral shape in order to show the evolutionary relatedness among species over time. The models accurately depict a modern phylogenetic tree, along with a time scale and illustrations of various plants, animals, fungi, insects, and bacteria. Opposite Darwin's illustration, which has often led