ALGAL CLASSIFICATION

By :- Aman Kumar M.Sc. (P)

Botany Roll No. - 02

CONTENTS INTRODUCTION CRITERIA OF CLASSIFICATION IMPORTANT SYSTEMS OF ALGAL

CLASSIFICATION REFERENCES

INTRODUCTION Algae comprise a group of autotrophic,

chlorophyll containing thalloid plants of simplest type having no true root, stem and leaves.

On the basis of their colours 4 groups were recognised :-

1. Myxophyceae or Cyanophyceae (Blue green algae)

2. Chlorophyceae (Green algae)3. Phaeophyceae (Brown algae) 4. Rhodophyceae (Red algae)

Criteria of classification1. Algal pigments 2. Reserve foods3. Flagellation 4. Chloroplast 5. Eye spot

Algal pigments Chlorophyll

Chlorophyll a Chlorophyll b Chlorophyll c Chlorophyll d

Chlorophyll e(Primary photosynthetic (Found In Chlorophyceae , (Present in Dinophyceae (Found in many

(Found in only Pigment found in all Charophyceae , Cryptophyceae , Rhodophycean in

two genera Photosynthetic algae) Euglenophyceae ) Chrysophyceae , members )

of Xantho Bacillariophyceae ,

phyceae, Xanthophyceae ,

Tribmonema , Pheaophyceae )

Vaucheria )

Insoluble in water and petroleum ether but soluble in alcohol , benzene and acetone

Algal pigments CAROTENOIDS

Group of yellow , orange ,red and brown protective pigments. Acts as screen to light and pass light energy to chlorophyll. Soluble in alcohol , acetone , benzene, insoluble in water.

TWO TYPES CAROTENES :- 6 types ( α,β ,γ ,ε , Flavicine and lycopene ) In most of algae β carotene is present . In Bacilleriophyceae and some member of cryptophyceae ε carotene is

present. In Chlorophyceae α carotene is present . XANTHOPHYLL :- Fucoxanthin - Present in Chrysophyceae ,

Bacilleriophyceae ,Phaeophyceae . Peridinin - Found only in Dinophyceae. Myxoxanthin and Myxoxanthophyll - Found in cyanophyceae Taraxanthin - Found in Rhodophyceae Antheraxanthin - Found in Euglenophyceae .

Algal pigments PHYCOBILINS

Water soluble blue or red pigments Tetrapyrrolic compounds joined to globin protiens Present in Cyanophyceae, Rhodophyceae,Cryptophyceae

3 types on the basis of absorption spectra

Phycocyanin :- Found in Cyanophyceae Phycoerythrin :- Found in Rhodophyceae Allophycocyanin :- Found in Cyanophyceae and Rhodophyceae

Reserve foods Polysaccharides in which glucose subunits joined with

α -1,4 linkages are :-A. Starch ( Chlorophyceae and Charophyceae )B. Floridean starch ( Rhodophyceae )C. Myxophycean starch ( Cyanophyceae)

Polysaccharides with β -1,3 linkages are :-

D. Laminarin (Phaeophyceae )E. Chrysolaminarin (Chrysophyceae &

Bacillariophyceae) F. Paramylon ( Euglinophyceae )

Flagella(Present in all classes of algae except Cyanophyceae

and Rhodophyceae )

2 types :-A. Acronematic / Whiplash :- Smooth, do not have hairs on its surface.B. Pantonematic /tinsel :-have hairs on its surface.

Algal class Flagellar conditions ChlorophyceaeXanthophyceae ChrysophyceaeBacillariophyceaeDinophyceaeCryptoceaeEuglenophyceaePhaeophyceae

2 or 4 anterior , equal ,acronematic2 unequal, anterior, 1 acronematic 1 pantonematic2, 1 acronematic and 1 pantonematic1 pantonematic, anterior1 acronematic, 1 band shaped2 equal, lateral , pantonematic1 anterior , pantonematic2 unequal, lateral, 1 acronematic, 1 pantonematic

CHLOROPLAST Cyanophyceae - Double membrane bound chloroplast absent. Thylakoids are free. Chlorophyceae- Bound by double membrane of chloroplast. Thylakoids occur in bands of 2-6. Charophyceae - Bound by double membrane of chloroplast. Rhodophyceae- Bound by double membrane and thylakoids are free. Euglenophyceae - Chloroplast envelope is surrounded by one membrane of

chloroplast endoplasmic reticulum (CER). Xanthophyceae - Chloroplast envelope is surrounded by two membranes of CER. Thylakoids are grouped in bands of three. Phaeophyceae - Chloroplast envelope is surrounded by two membranes of CER. Thylakoids are grouped in bands of three. Bacillariophyceae- Chloroplast envelope is surrounded by two membranes of CER. Chrysophyceae- Chloroplast envelope surrounded by two membrane of CER.

EYE SPOTS Eye spot are not found in Cyanophyceae,

Bacillariophyceae and Rhodophyceae .3 types

Eye spot is a part of chloroplast but not associated with flagella : Chlorophyceae and Chrysophyceae .

Eye spot is a part of chloroplast but associated with flagella : Cryptophyceae , Xanthophyceae and Pheaophyceae.

Eye spot is independent of chloroplast but adjacent to flagella : Eugelenophyceae and some Xanthophyceae .

In Dinophyceae eye spot range from collections of lipid globules containing carotenoids and lacking membrane to more complex arrays of lipid containing globules.

IMPORTANT SYSTEM OF CLASSIFICATION

Smith’s system of classificationFritsch’s system of classificationClassification proposed by PapenfussClassification by PrescottRound’s system of classificationChapman and Chapman system of classification

Smith’s system of classification(1933,51,55)

Classified algae into 7 divisions and divisions into different classes on the basis of :-

Physiology of vegetative cells. Morphology of motile reproductive cells . Reserve foods. Photosynthetic pigments.

Smith’s system of classification(1933,51,55)

Division Class Example1. Chlorophyta 1. Chlorophyceae

2. Charophyceae Volvox , OedogoniumChara, Nitella

2. Euglenophyta 1. Euglenophyceae Euglena, Astasia3. Cyanophyta 1. Cyanophyceae Nostoc, Anabaena 4. Pyrrophyta 1. Desmophyceae

2. DinophyceaeDesmomastixDinophysis

5. Chrysophyta 1. Chrysophyceae2. Xanthophyceae3. Bacillariophyceae

ChrysodendronBotrydiumPinnularia

6. Phaeophyta 1. Isogeneratae 2. Heterogeneratae3. Cyclosporae

Ectocarpus , DictyotaLaminariaFucus

7. Rhodophyta 1. Rhodopyceae Porphyra

Fritsch’s system of classification(1935,48)

Classified algae into 11 classes on the basis of :-

Structure of plant body. Nature of pigment. Method of reproduction. Flagellar condition.

Fritsch’s system of classification(1935,48)

These classes are :-1. Chlorophyceae (Isokontae)2. Xanthophyceae (Heterokontae)3. Chrysophyceae 4. Bacillariophyceae (Diatoms)5. Cryptophyceae6. Dinophyceae (Peridinieae)7. Chloromonadineae 8. Euglenineae 9. Phaeophyceae 10. Myxophyceae (Cyanophyceae)11. Rhodophyceae

Classification proposed by Papenfuss

(1955) On the basis of phylogeny recognised 8

phyla and 12 classes in algae :- Phyla Classes 1. Chlorophycophyta Chlorophyceae

2. Charophycophyta Charophyceae

3. Euglenophycophyta Euglenophyceae

4. Chrysophycophyta Chryophyceae

Xanthophyceae

Bacillariophyceae

5. Pyrrophycophyta Cryptophyceae

Chloromonadophyceae

Dinophyceae

6. Phaeophycophyta Phaeophyceae

7. Rhodophycophyta Rhodophyceae

8. Schizophycophyta Schizophyceae

Classification proposed by Prescott(1969)

Round’s system of classification(1973)

ALGAE

PROCARYOTA EUCARYOTA

CYANOPHYTA CHLOROPHYTA EUGLENOPHYTA

CHAROPHYTA PARSINOPHYTA XANTHOPHYTA

HAPTOPHYTA DINOPHYTA

BACILLARIOPHYTA CHRYSOPHYTA

PHAEOPHYTA RHODOPHYTA CRYPTOPHYTA

Chapman and Chapman system of classification (1973)

Division Class

PROCARYOTA CYANOPHYTA (blue-green algae)

Cyanophyceae

EUCARYOTA RHODOPHYTA(red algae)

Rhodophyceae

CHOLOPHYTA(green algae)

Cholophyceaeprasinophyceae

EUGLENOPHYTA(euglenoids)

Euglenophyceae

CHLOROMONADOPHYTA(chloromonads)

Chloromonadophyceae

XANTHOPHYTA(yellow-green algae)

Xanthophyceae

BACILLARIOPHYTA(diatoms)

Bacillariophyceae

CHRYSOPHYTA(golden brown algae)

Chrysophceae haptophyceae

PHAEOPHYTA(brown algae)

Phaeophyceae

PYRROPHYTA (dinoflagellates)

DinophyceaeDesmophyceae

CRYPTOPHYTA (cryptomonads)

Cryptophyceae

REFERENCES

Kumar, H.D. (1999): Introductory Phycology Affiliated East West Press Ltd., New Delhi.

Singh, V.(2013) :A text book of Botany, Rastogi Publications, Meerut,India.

Vashishta,B.R(1960) : Botany for degree students, Algae, S.Chand Publishing , New Delhi.

THANK YOU