A V0-morph is an

organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...

whose surface area remains constant as the organism grows. The reason why the concept is important in the context of the

Dynamic Energy Budget The dynamic energy budget (DEB) theory is a formal metabolic theory which provides a single quantitative framework to dynamically describe the aspects of metabolism (energy and mass budgets) of all living organisms at the individual level, based o ...

theory is that food (substrate) uptake is proportional to surface area, and maintenance to volume. The surface area that is of importance is that part that is involved in substrate uptake.

Biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

s on a flat solid substrate are examples of V0-morphs; they grow in thickness, but not in surface area that is involved in nutrient exchange. Other examples are

dinophyta The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

and

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

s that have a cell wall that does not change during the cell cycle. During cell-growth, when the amounts of protein and carbohydrates increase, the vacuole shrinks. The outer membrane that is involved in nutrient uptake remains constant. At cell division, the daughter cells rapidly take up water, complete a new cell wall and the cycle repeats. Rods (bacteria that have the shape of a rod and grow in length, but not in diameter) are a static mixture between a V0- and a

V1-morph An V1-morph is an organism that changes in shape during growth such that its surface area is proportional to its volume. In most cases both volume and surface area are proportional to length The reason the concept is important in the context of th ...

, where the caps act as V0-morphs and the cylinder between the caps as V1-morph.The mixture is called static because the weight coefficients of the contributions of the V0- and V1-morph terms in the

shape correction function The shape correction function is a ratio of the surface area of a growing organism and that of an isomorph as function of the volume. The shape of the isomorph is taken to be equal to that of the organism for a given reference volume, so for that pa ...

are constant during growth. Crusts, such as

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.shape correction function The shape correction function is a ratio of the surface area of a growing organism and that of an isomorph as function of the volume. The shape of the isomorph is taken to be equal to that of the organism for a given reference volume, so for that pa ...

change during growth. The

theory explains why the diameter of crusts grow linearly in time at constant substrate availability.

References

See also