Difference Between Chlamydomonas and Spirogyra

The key difference between Chlamydomonas and spirogyra is that Chlamydomonas is a single-celled spherical-shaped green alga which is highly motile while spirogyra is a multicellular filamentous green alga which has spirally arranged chloroplasts.  

Green alga is a group of algae belonging to Kingdom Protista. Similar to land plants, they have a cellulose cell wall, chlorophyll a and b, chloroplasts and starch. They are considered precursors for land plants. Chlorophytes and charophytes are the major divisions of green algae. Chlamydomonas and spirogyra are two green algae. Chlamydomonas is a unicellular microscopic spherical alga while spirogyra is a filamentous and multicellular green alga. Chlamydomonas have a cup-shaped large chloroplast while spirogyra contains a helical-shaped chloroplast. Chlamydomonas is a chlorophyte while spirogyra is a charophyte.

CONTENTS

1. Overview and Key Difference
2. What is Chlamydomonas
3. What is Spirogyra
4. Similarities Between Chlamydomonas and Spirogyra
5. Side by Side Comparison – Chlamydomonas vs Spirogyra in Tabular Form
6. Summary

What is Chlamydomonas?

Chlamydomonas is a unicellular spherical-shaped green alga. It possesses two flagella; hence it is highly motile. These flagella show whip-like lashings in order to pull Chlamydomonas in water. It is microscopic and lives in stagnant water, freshwater, seawater and damp soil. It possesses a central nucleus and a cytoplasm enclosed in a cell wall. There is a single cup-shaped large chloroplast inside the Chlamydomonas cell. It also possesses a light-sensitive red pigment spot in the region of cytoplasm near the origin of the flagella. This eyespot can detect the direction of a light source.

Chlamydomonas is mainly photosynthetic. But, it also can absorb nutrients through the cell surface. Reproduction of Chlamydomonas takes place via both sexual (formation of gametes) and asexual methods (by means of zoospores).

What is Spirogyra?

Spirogyra is a multicellular filamentous green alga found mainly in freshwater habitats. It has a ribbon-like appearance. Spirogyra belongs to division Charophyta, and there are around 400 spirogyra species. Spirogyra has rectangular shaped cells connected end to end in long filaments. Each cell has a helical-shaped chloroplast, nucleus, cytoplasm and a vacuole. Therefore, they can photosynthesize. Each cell is surrounded by a cell wall.

Spirogyra shows the sexual reproduction method of conjugation. Two spirogyra filaments (which are lying parallel to each other) form a conjugation tube and reproduce sexually. Moreover, spirogyra reproduces asexually through simple fragmentation of the filaments. Single cells break off and undergo binary fission or mitosis to produce more genetically identical spirogyra cells. In addition, spirogyra produces zygospores in order to survive under harsh environmental conditions.

What are the Similarities Between Chlamydomonas and Spirogyra?

• Both Chlamydomonas and Spirogyra are green algae.
• They belong to Kingdom Protista.
• Both can move.
• They are photoautotrophs, so they carry out photosynthesis.
• They possess chloroplasts and chlorophylls.
• Moreover, they possess a cellulose cell wall.
• They also possess a nucleus and vacuoles.
• Both reproduce via sexual and asexual methods.

What is the Difference Between Chlamydomonas and Spirogyra?

Chlamydomonas is a spherical shaped unicellular green alga while spirogyra is a filamentous multicellular green alga. So, this is the key difference between Chlamydomonas and spirogyra. Moreover, there is a cup-shaped large chloroplast in Chlamydomonas while there is a helical-shaped chloroplast in spirogyra. Thus, this is another significant difference between Chlamydomonas and spirogyra.

The below info-graphic lists more differences between Chlamydomonas and spirogyra in tabular form.

Summary – Chlamydomonas vs Spirogyra

Chlamydomonas is a spherical shaped unicellular green alga. Spirogyra is a filamentous multicellular green alga. Chlamydomonas has a cup-shaped large chloroplast while spirogyra has a helical-shaped chloroplast. Chlamydomonas reproduces asexually by means of zoospores while spirogyra reproduces asexually by fragmentation. Moreover, Chlamydomonas reproduces sexually by the formation of gametes while spirogyra reproduces sexually by conjugation. Chlamydomonas is found in stagnant water and damp soil mainly. Spirogyra is mainly found in freshwater. Thus, this summarizes the difference between Chlamydomonas and spirogyra.

Reference:

1.Caprette, David R. “Chlamydomonas as a Model Organism.” Introductory Laboratory Courses in Biochemistry & Cell Biology, Rice University, Available here.
2. “Spirogyra.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.

Image Courtesy:

1. “Chlamydomonas reinhardtii vector scheme” By Nefronus – Own work (CC0) via Commons Wikimedia
2. “The freshwater alga Spirogyra” By Wiedehopf20 – Own work (CC BY-SA 4.0) via Commons Wikimedia