Growth Forms
Unicellular
Organisms that are composed of single cell
The earliest life was unicellular
Both prokaryotes and eukaryotes have unicellular members
e.g., bacteria, Chlamydomonas
Unicellular
Plasmodial
Organisms that are composed of single visible, blob-like cell
The large cell is composed of many nuclei. This is called coenocytic
These organisms are usually probing and exploring the landscape for a food source
e.g., plasmodial slime molds (Mycetozoa)
Colonial
Organisms composed of many unicellular organisms "tethered" together
They communicate with one another to act as a functional large organism
e.g., Volvox
Multicellular
Organisms that are constructed of two or trillions of cells
These cells are connected and communicate with each other for survival
Both prokaryotes and eukaryotes have multicellular members but they evolved independently
Filamentous
This growth form is hair-like or strand-like
There are many cells connected linearly, creating a chain
When a cell divides, it does so in just one plane or a single orientation
e.g. Oscillatoria, Spirogyra
Branched filamentous
This is also a strand-like form of growth but with side branches
Cells are connected linearly with occasionaly strands that branch off from main filament
Most growth is in one plane, but when a branch is formed, this requires two planes of division: one continues the filament, and the other creates the branch
Multicellular
Siphonous
This growth form is tube-like but lacks the connection of many small cells like filamentous forms
Siphonous organisms usually have a few elongated cells that lack cross-walls
Because of their larger size, these cells tend to have many nuclei (coenocytic)
e.g. Polysiphonia
Multicellular
Thalloid
Having a flattened, splayed-out form of growth
Thalloid organisms usually grow flat against soil, rocks, or other substrates
It is found in some macroscopic algae, plants, fungi, and lichens
Thalloid organisms may be parenchymatous or pseudoparenchymatous
Multicellular
Parenchymatous
Parenchyma looks like thin-walled, bubble-like cells
In functionality, plants use these cells to store materials such as water and starches or even house chloroplasts for photosynthesis
Parenchyma is a type of tissue composed of cells interconnected in three dimensions (i.e., cells are connected above, below, and on the sides of each other)
Cell division in three planes or orientations creates this three-dimensional construction
e.g. plants
Multicellular
Pseudoparenchymatous
Composed of branching, filamentous strands interwoven into a mass that makes up the organism’s body
It uses the ability to do filamentous growth and then interlace multitudes of strands to create a larger body mass
It appears parenchymatous but lacks a 3D connection of cells
e.g., mushrooms
