Re: How do the Blue Green algae (Moneran) grow and develop?

First let me point out that the five kingdom system, which includes Monera, is obsolete. Today, we classify organisms into three domains. Two of which are prokaryotic and one eukaryotic. The Eubacteria includes what would be much of the old Monera designation, the bacteria. The Archeae include many perhaps more ancient forms of prokaryotes that share some close phylogenetic relationships with the eucaryotic group. The Eucarya includes all of the organisms formerly divided into the other four kingdoms, animals, plants, fungi, and protista. The five kingdom system overemphasizes the importance of the eukaryotes and misses the real diversity and dominance of the prokaryotes.

On to your question. Bluegreen algae, the cyanobacteria, are a diverse group of organisms. Some scientists have divided the cyanobacteria into classes based on their morphology (how they look) and how they reproduce. As you likely know, a single, parent, bacterial cell will grow and divide into two daughter cells. This process is called binary fission and is common among cyanobacteria that live mainly as single cells. In some cases, two binary fission events can occur giving four cells that remain together as a tetrad, essentially a colony made up of four cells held together with some algal slime.

There are other groups of cyanobacteria that form filaments. Here the cells form a chain that looks something like a stack of poker chips. Individual cells still grow and divide through binary fission, but the daughter cells remain attached as part of the filament. Some species form bundles of filaments. Filaments can be straight chains without branches. Filaments can also be found that contain branches. Many species of cyanobacteria also form specialized cells that have differentiated from normal (vegetative) cells into cells that have unique features and structures. There are specialized cells called akinetes that act as tough seed-like or spore-like cells. Other specialized cells called heterocysts are used for converting (fixing) nitrogen gas from the atmosphere into ammonia.

Cyanobacteria are often found in nature living as part of attached biofilms, although they can also be found as free-living (planktonic) cells and filaments. Biofilms are spongy mixtures of cells and extracellular polysaccharide slimes. These can form on any surface such are rocks in a lake, tidal areas near the ocean, and even the crusts of arid soils. As I have said, cyanobacteria are very diverse and occupy a great number of habitats. Some even live within the rocks of Antarctic deserts (the endolithic cyanobacteria). Some cyanobacteria live within other organisms, such as sugar cane. You can likely find cyanobacteria growing around your school. Look for bare soil areas that have dried out and don't get very much foot traffic. If you see the greenish or blackish crusts on the soil kind of curling on the edges, that is likely a dried cyanobacteria mat. Look at the outside walls of the building. Perhaps there are black stains near a place where water might leak from a drain pipe. Again, this is likely a cyanobacterial biofilm. You might also find some lichens growing on trees or rocks. These are often a mixture of cyanobacteria and fungi. Very diverse. Very widespread.

I hope this helps.

Cheers,

Mark.