General account classification biochemistry evolution economic importance

1. Rhodophyta

2. Presented by:
Muhammad Sohail Riaz
Presented to:
DR Umair Ahmad Awan

3. Table of Contents
 General account
 Evolution
 Classification
 Bio-chemistry
 Economic importance

4. General Account
 Also called as Red Algae
 All species are multicellular
 One of the oldest groups of eukaryotic algae
 Also comprises one of the largest phyla of algae
 Predominately marine about 98%
 Red algae are commonly found in the depths of
oceans
 Occur in all oceans but few in polar seas

5. Cont…..
 Marine form recognize by their bright color
 Fresh water forms are bluish green color
 They live attached to rocks by a structure called
holdfast
 5250 species and 831 genera are known
 Reproduction is very complex process in these
organisms
 Sexual and A-sexual reproduction is present while
vegetative reproduction is very rare

6. Cont……
 Cell is typically eukaryotic
 Their cell wall contain thick polysaccharides
 Protoplast is surrounded by two layered cell wall
 Inner consisting of cellulose and outer with pectin
material
 Some red algae’s cell wall contain xylans
 Reserved food stores as a complex carbohydrates
 Endoplasmic reticulum, Mitochondria and
Dictyosomes are present in rhodophytes

7. Systematics Position
 Division : Rhodophycophyta
 Class : Rhodophyceae
 Sub-class : Florideae
 Order : Gelidiales
 Family : Gelidiaceae
 Genus : Gelidium
 Specie : Cartilagineum

10. EvolutionEvolution
 According to Schopf, Rhodophyceae is an ancient
 Fossils of red algae are known from Cambrian
 According to Klein and Cronquist, Rhodophytes
were “probably derived from cyanophytes”, with a
cyanidium like alga as a possible link between these
two groups
 Earlier rhodophytes were unicellular, from which
evolved the filamentous rhodophytes

11. Cont…..Cont…..
 According to Kohlmeyer, red algae gave rise to
higher fungi, through loss of plastids
 According to Lee, there is no agreement amongst
phylogenist whether or not the two major groups
are two “Natural groups derived from two separate
line of evolution
 According to Scagel et.al, Conchocelis stage of
Bangia and Porphyra represents a link between
Bangioideae and Florideae

12. Bio-chemistry
 Photosynthetic pigments of rhodophyta are
chlorophyll a and b
 Red algae are red due to phycoerythrin
 Red algae contain sulfated polysaccharide
carrageenan in the amorphous section of their cell
wall
 Red algae also produce a specific type of tannin
called Phlorotannins, but in lower amount than
brown algae do

13. Classification
 Based on thallus organization and post fertilization
changes, Fritsch divide into two classes:
1. Bangioideae
2. Florideae

14. Cont……..
 The sub-classes was further divided into six orders:
i. Nemalionales
ii. Gelidiales
iii. Cryptonemiales
iv. Gigartinales
v. Rhodymeniales
vi. Ceramiales

15. Cont…….
 Smith raised the class rhodophyaceae to the rank of
division and named it as rhodophyta
 V.J Chapman and D.J Chapman placed
rhodophyaceae into phylum rhodophyta and divide
into sub-classes:
1. Bangiophycidae
2. Florideophycidae
 Bangiophycidae divided into five orders
 Florideophycidae divided into seven orders

16. Cont…..

17. Economic Importance
 Red algae is high in vitamins, minerals and
antioxidants that are easily utilized by your body
 Associated with the production of polysaccharides
 Agar is delicacy in Japan which is jelly like food
 Agar provide a polysaccharide gel, which is non-
toxic, solid and cannot be digested
 Agarosa, an alternate polysaccharide sold at great
expense

18. Cont…..
 Nori used for wrapping sushi, rice cracker, topping
on rice
 Porphyra japonica is eaten in Japan
 The cultivation of nori is a substantial industry
 The main benefits of red algae is its ability to
promote healthy circulation in your body, regulate
your blood sugar levels and lower bad cholesterol
levels since it is high in dietary fiber
 The red algae furnish food for sea animals

19. Cont…..
 Calcareous red algae like Lithothamnion,
Lithophyllum, Porolithon and Goniolithon play an
important role in the formation of coral reefs

21. Thank you