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Unicellular
Unicellular
Microscopic unicell
Microscopic unicell
Organisms that are composed of single cell
The earliest life was unicellular
Both prokaryotes and eukaryotes have unicellular members
Cell division (mitosis) results in two new and unconnected cells
e.g., bacteria, Chlamydomonas
Right: The microscopic unicellular green algae, Chlamydomonas
Plasmodial unicell
Plasmodial unicell
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)
Right: The plasmodial slime mold, Physarum, which is a single blob-like cell
Colonial
Colonial
Possessing multiple unicells that function together in an organismal way
Filamentous
Filamentous
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, unbranched
Filamentous, unbranched
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
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
e.g., Stylonema
Right, top: an unbranched, filamentous green algae, Spirogyra
Right, bottom: A branched, filamentous red algae, Stylonema
Siphonous
Siphonous
This growth form is tube-like but lacks the connection of many small cells like filamentous forms
While a siphonous strand is unicellular, most organisms usually have a few, connected, elongated cells that lack cross-walls
Because of their larger size, these cells tend to have many nuclei (coenocytic)
e.g., Polysiphonia, Caulerpa, Cladophora
Above: the green alga Caulerpa with its frond-like siphonous cells. These are some of the largest single cells in the world.
Left: A close-up of a siphonous cell of a green alga, Cladophora
Pseudoparenchymatous
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
Parenchymatous
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
Thalloid
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 (e.g., liverworts) or pseudoparenchymatous (e.g., some red algae)
Right: the thalloid form of a liverwort, Marchantia
Unicellular
Unicellular
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