The classification of algae has been debated and revised over time as new evidence emerges. Early classifications by Fritsch in 1935 and Smith in 1950 focused on characteristics like pigmentation, flagella, food storage, and cell structure. Later classifications, such as by Bold and Wynne in 1985 and Lee in 1989, considered evolutionary relationships and the number of chloroplast membranes. Lee's 1989 classification divided algae into 4 evolutionary groups based on chloroplast structure. Ongoing research continues to refine algal taxonomy as new discoveries are made.
2. For diverse reasons, the taxonomy of
algae is not settled yet. There is still
an ongoing battle about the
composition of eukaryotic
supergroups, for example, and until
that is resolved, it can be hard to
define taxonomic levels included
within supergroups.
3. Basis for Classification of Algae
The primary classification of algae is based on the
following five criteria:
Photosynthetic apparatus and pigments
Nature of reserve food
Nature of cell wall components
Type, number and attachment of flagella
Cell structure
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4. 1. F.E. Fritsch’s Classification
(1935)
2. G.M. Smith’s Classification
(1950)
3. Round’s Classification (1973)
4. Bold and Wynne’s
Classification (1985)
5. Robert Edward Lee’s
Classification (1989)
6. The most comprehensive and authorative
classification of algae was given by F.E
Fritsch (1935) in his book ‘The Structure
and Reproduction of the Algae’.
His classification was based on such
criteria as pigmentation, types of flagella,
assimilatory products, thallus structure
and methods of reproduction.
7. F.E. Fritsch (1935, 1948) divided algae
into 11 classes on following basis:
Number and mode of attachment
of flagella in the motile cells
Thallus structure
Chemical nature of pigments
Reserve food materials
Method of reproduction
Variation in the life cycles
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10. GM Smith (1950) classified algae
into seven divisions. These
divisions include one or more
classes. He included certain algae
of uncertain position into
Chloromonadales & Cryptophyceae.
Smith’s Classification
13. Bold and Wynne (1978, 1985)
recognized ten divisions of algae
retaining the nomenclature given by
Papenfuss (1946), except for blue-
green algae. They considered
Cyanophyceae as a division and
called it Cyanochloronta whereas
Papenfuss had included it in phylum
Schizophyta as a class.
Bold and Wynne’s Classification
15. Robert Edward Lee’s
Classification
RE Lee (1989) divided the
algae based on evolution and
formed 4 evolutionary
groups of algae which are
further divided into 15 phyta
(=divisions).
16. 1. Prokaryotic algae (Cyanophyta)
2. Eukaryotic algae with chloroplast surrounded
only by the two membranes of the chloroplast
envelope (Glaucophyta, Rhodophyta and
Chlorophyta)
3. Eukaryotic algae with chloroplast surrounded
only by one membrane of chloroplast endoplasmic
reticulum (Euglenophyta and Dinophyta)
4. Algae which have two membranes of chloroplast
endoplasmic reticulum (Cryptophyta &
Heterokontophyta)
17. Characteristics Fritsch’s classification Bold and
Wynne’s classification Lee’s classification
Number of divisions No divisions 9
15 divisions in 4
groups
Number of classes 11 – –
Position of BGA and
Prochloron
In the eleven numbered class
called Mycophyceae
As two separate divisions
known as Cyanochloronta and
Prochlorophyta
Alone in the first
group called the
prokaryotic algae
Classification basis
Pigmentation
The metabolic or assimilatory
food products
Types of flagella
Pigmentation
Storage product
Cellular organisation
Cell wall chemistry
Flagellation
Evolution of
chloroplasts
Division:
Glaucophyta and
Dinophyta
Absent Present
Division: Charophyta Present Absent