Erythropoiesis. The process through which new red blood cells are created; it begins in the bone marrow. Mentioned in: Porphyrias. the formation of red blood cells (erythrocytes) from stem cells in the bone marrow.
2 Unicelluar organisms are one-celled organisms or microorganisms. Although they are living things that are only one cell, they still need to carry out all 6 characteristics of life. For example, they must feed, digest, excrete wastes and reproduce. They are very small and surround you every day by the millions.
Unicellular organisms are known as single-celled organisms. They are made up of a single cell. Organisms like the amoeba, Paramecium are single-celled organisms, they are the oldest forms of life, they existed about 3.8 million years ago. Bacteria, archaea, protozoa, unicellular algae and unicellular fungi are the main groups of unicellular organisms. The single-cell regulates all the activity of the organism. Unicellular organisms are small are mostly invisible to the naked eye. There are two general categories of unicellular organisms: prokaryotic and eukaryotic organisms. Prokaryotic unicellular organisms are protists and some fungi. Some of these unicellular prokaryotes live in colonies. They live together and all the cells of the colony is the same. All the process of life is carried out in each cell in order for the cell to survive. Simplest multicellular organisms are made of cells that dependent on each other for their survival. Most of the multicellular organism are microscopic and are known as microscopic organisms. Unicellular organisms vary in size.