What is the difference between a Pennate and a centric diatom?

Centric diatoms (order Centrales) have radially arranged markings. Pennate diatoms (order Pennales) have markings bilaterally arranged about the valve’s long axis.

Is a Pennate diatom?

Pennate diatoms are bipolar, elongate and bilaterally symmetric, although quite a few taxa are bilaterally asymmetric. In older taxonomic systems, pennate diatoms are contrasted with the centric diatoms. These two groups are not natural, evolutionary lineages but serve as general descriptions of morphology.

What are the different types of diatom?

There are two types of diatoms found in nature. One is round, while the other is elongated. Diatoms are divided into two categories based on their form: pennate diatoms and centric diatoms.

Are Pennate diatoms motile?

Behaviour. Most centric and araphid pennate diatoms are nonmotile, and their relatively dense cell walls cause them to readily sink.

Do centric diatoms have raphe?

Taxonomically, diatoms are divided into two groups based on the symmetry of the cells. Centric diatoms (order Centrales) have radially arranged markings. Diagram showing the diatom mobility using raphe. Cell Division (Asexual Reproduction).

What is a raphe in a diatom?

The raphe is a structure that allows diatom cells to move over surfaces. The raphe system is composed of one or two slits, or fissures, that penetrate the valve of some diatoms. If two slits are present, each is called a branch of the raphe. Branches may be separated by a silica thickening called the central nodule.

What order are diatoms?

Diatoms are Eukaryotic and belong to the Kingdom protista. They further belong to the super group Chromalveolata and are grouped into the Strameopiles as the lineage Diatoms. They then form two phyla, Bacillariophyta and Chrysophyta. They are then divided into 2 orders in each phyla.

What are marine diatoms?

Diatoms are single-celled photosynthetic organisms. Their cell walls are composed of two interlocking silica halves. These sink to the ocean floor when diatoms die, becoming part of the sediment. As they stay preserved for millions of years, fossil diatoms are a valuable record of past oceanic environments.

Which is not associated with diatoms?

Nostoc is classified as blue – green algae, and also as a cyanobacterium. It is photosynthetic, and one of the oldest living organisms on this planet. Despite these features, Nostoc’s cell wall is made of peptidoglycans and an outer lipid and protein membrane. It is therefore not a diatom.

Do all diatoms have a raphe?

Many (but not all) pennate diatoms have a raphe, which is a longitudinal groove involved with gliding motility. The mechanism for gliding mobility is still under investigation. The raphe is also involved in mucilage secretion in some species, and can anchor the cell to the substrate.

What is the difference between dinoflagellates and diatoms?

The key difference between diatoms and dinoflagellates is that the diatoms have a cell wall composed of silica while the dinoflagellates have a cell wall composed of cellulose. Phytoplanktons are algae that are single-celled eukaryotic cells. There are many types of phytoplankton.

https://www.youtube.com/watch?v=lCkoQeMWBqY