20+ General Characteristics of Algae

In this article, we will be discussing 20+ General Characteristics of Algae. Algae belong to the Thallophytes of the Plant Kingdom. The term Algae was given by C. Linneaus. The branch of biology that deals with the study of Algae are known as Phycology or Algology. The Father of Phycology is F. E. Fritsch who has written the book ‘Structure and Reproduction in Algae’. The father of Indian Phycology is M.O.P. Iyenger.

Also Read: Introduction to Algae and Historical Developments in Algology

20+ General Characteristics of Algae

1. These are mostly Aquatic however they are also found in other habitats too.
2. These are also found to have a symbiotic association with Fungi as ‘Lichens’.
3. The cell structure is Eukaryotic, mesokaryotic and prokaryotic. Mostly Eukaryotic, however there some are prokaryotic spieces are also found (Cyanobacteria or BGA). The mesokaryotic cell structure can be seen in Dinophyceae.
4. All most all Algae except Cynophyceae have well organized Eukaryotic Nucleus.
5. Some Algae have Flagella for locomotion. They have a 9+2 arrangement of microtubules.
6. They consist of Holdfast which helps to anchorage to the substratum.
7. They have a thallus body structure where the body is not differentiated into true root, stem and leaves. 
8. There is little or no differentiation of tissues in Algae.
9. These are unicellular or multicellular. 
10. Multicellular algae consist of some specialised tissues but they also have thalloid bodies.
11. These are Autotrophic and have Chloroplast containing Chlorophyll which helps to prepare their own food by the process of photosynthesis.
12. These may be Photoautotrophic or Chemoautotrophic. 
13. Most of them are Photoautotrophic which prepare their food by utilising Sunlight. 
14. Some are Chemoautotrophic which prepare their food by utilising the energy released by Chemical reactions of organic compounds.
15. Algae have Pigmentation (colouring) due to which they have characteristic colours. There are three classes of photosynthetic pigments are found-
    1. Chlorophylls (5- types), 
    2. Carotenoids (6- types of Carotenes and 20- types of Xanthophylls) 
    3. Phycobilins (3- types). 
    4. Chlorophyll-a and β-carotene are found in all the algal groups. 
16. The algal cell wall is composed of Cellulose.
17. The reserve food material varies from one group to another. For example
    1. Starch (in Green Algae)
    2. Laminarin (in Brown Algae)
    3. Floridian Starch (in Red Algae)
    4. Cyanophycin (in BGA)
    5. Paramylon (in Euglenoids) etc.
18. Reproductive organs may be unicellular or multicellular. The Sex organs are unicellular and non-jacketed. When multicellular each cell is Fertile.
19. Reproduction takes place by vegetative, asexual and sexual types.
20. Vegetative Reproduction is by
    1. Fragmentation (e.g. Ulothrix, Oedogonium)
    2. Cell Division or Fission (e.g. Euglena, Chlamydomonas, Diatoms)
    3. Tubers (e.g. Chara)
    4. Hormogonia (e.g. Nostoc)
    5. Budding (e.g. Protosiphon)
    6. Formation of adventitious branches (e.g. Dictyota, Fucus)   
21. Asexual Reproduction is by
    1. Zoospores (e.g. Chlamydomonas, Oedogonium, Ectocarpus etc.)
    2. Aplanospores (e.g. Microspora and Ulothrix)
    3. Hypnospores (e.g. Pediastrum)
    4. Autospores (e.g. Chlorella)
    5. Tetraspores (e.g. Polysiphonia)
    6. Exospores (e.g. Chamaesiphon)
    7. Endospores (e.g. Dermocarpa)
    8. Carpospores and Akinetes etc. 
22. Sexual reproduction is also seen. But it is absent in Blue-Green Algae. Sexual Reproduction are of following types-
    1. Isogamous – e.g.: Ulothrix, Chlamydomonas etc.
    2. Anisogamous- e.g.: Ectocarpus, Spirogyra,Pandorina etc.
    3. Oogamous- e.g.: Volvox, Chara, Oedogonium etc.
    4. Autogamy- e.g.: Diatoms
    5. Hologamy- e.g.: Chlamydomonas, Dunaliella etc.
23. In sexual reproduction, the fusion of male and female gamete takes place to form Zygote. 
24. They have characteristic of Perennation which means that they can survive for years to pass through unfavourable conditions for their vegetative growth.
25. There are two phases of the Life Cycle seen- Gametophytic and Sporophytic. Both of them are independent of each other. There is no embryo formation after fertilisation in the life cycle. Under Favourable condition reproduces asexually by mitospores (formed after mitosis).
26. There are four main types of Life-Cycles patterns seen. They are 
    1. Haplontic Life Cycle (Oedogonium, Chlamydomonas, Chara, Spirogyra & Xanthophyceae members)
    2. Diplontic Life Cycle (Bacillariophyceae, Fucus and Sargassum)
    3. Diplohaplontic Life Cycle
       1. Isomorphic Diplohaplontic Life Cycle (Ulvales, Cladophorales)
       2. Heteromorphic Diplohaplontic (Laminaria)
    4. Triphasic Life Cycle
       1. Haplobiontic (Batrachos­permum)
       2. Diplobiontic (Polysiphonia)

The above mentioned are the important General Characteristics of Algae. Hope these above-listed characteristics will help you with your study and also exam. In the next article, we will be discussing more topics and notes related to B.Sc. and M.Sc. Botany. Do share these notes with your friends, classmates. And do give us your feedback in the comment box below or you can also contact us.