Question

To explain the following concerning Cyanobacteria in general.

1) general characteristics

2) Type of reproduction and how

3) Why important evolutionarily, ecologically, and economically?

Answer 1

General Characteristics of Cyanobacteria

1. They are procaryotes and mostly found in acquatic environment .

2. Cynobacteria are autotrophs ,blue green in color due to presence of pigment called phycocyanin (some are red due to presence of phycoerythrin )and have internal membranes which is the site for photosynthesis .

3.They are found both as unicellular and filamentous forms

4. They can fix atmospheric nitrogen under anaerobic conditions into ammonia, nitrites and nitrates .

Reproduction in cyanobacteria

In unicellular cyanobacteria-Reproduction is asexual and by binary fission or multiple fission .

In filamentous cynobacteria - By fragmentation or spore formation .

Cyanobacteria also have some alternative parasexual pathways.

Evolutionary Importance of Cyanobacteria

Cynobacteria has formed earths early atmosphers rich in oxygen and supported other life forms . Many proterozoic

oil deposits are formed due to cyanobacteria .

Ecological importance of Cyanobacteria .

They are able to colonise the barren land first and hence allow the other forms of life to colonise later by improving the soil fertility .

Economical Importance of Cyanobatcteria

They are of used as food source for humans and some other animals .eg. spirulina due to its high protein content . Also used as mannure .