3. CHARACTERISTICS OF ALGAE
AQUATIC
AUTROPHIC MODE OF NUTRITION
CHLOROPHYLL
UNICELLULAR SEX ORGAN
INDEPENDENT GAMETOPHTIC AND SPOROPHTIC PHASE
GAMETOPHYTIC PHASE IS DOMINANT
4. PIGMENT
All algae contain chlorophyll pigment A
Chlorophyll A and B (all green algae and Euglena)
Chlorophyll A and C (Brown algae)
Chlorophyll A, Phycoerythrin and Phycocyanin
(Red algae)
5. CLASSIFICATION OF ALGAE
Based on Photosynthetic
pigment, stored food and
cell wall composition
Chlorophyceae Phaeophyceae Rhodophyceae
7. Chlorophyceae (Green Algae)
Green color (Dominant
chlorophyll a and B
Carotenoids are also present
Plant body is thallus
Unicellular- eg: Chlamydomonas
Colonial- eg: Volvox sp.
Filamentous- eg: Spirogyra
Source:Spirogyra- QS study
8. Chlorophyceae (Green Algae)
Chlorophylls and Carotenoids
are localized in Chloroplast
Chloroplast are of different
shapes:
1.Discoid
2.Plate –like
3.Reticulate (Oedogomium)
4.Cup Shaped ( Chlamydomonas)
5. Spiral or ribbon (Spirogyra)
Source:Spirogyra- Brittannica
9. Chlorophyceae (Green Algae)
Chlorophylls contain roughly
spherical body called pyrenoid.
Pyrenoids are absent in other
members of the plant kingsom.
Pyrenoids act as a centre of
carbon-di- oxide fixation to
increase the efficiency of
photosynthesis
Reserve food material is :
mostly starch around pyrenoids
Sometimes oil droplets.
Source:Spirogyra- Pininterest, Science direct
10. Chlorophyceae (Green Algae)
Algae in spacecrafts!!!
Algae Chlorella sp. are used:
To provide oxygen for the
astronauts
To consume the carbon di oxide
exhaled by them
Potential source of food and
energy
Source:: Spirogyra- Algal research supply
Reserve food
material is :
mostly starch
around
pyrenoids
Sometimes oil
droplets.
14. PHAEOPHYCEAE- Brown algae
Pigments
The brown color is due to the dominance of
fucoxanthin.
1. Other pigments are chlorophyll a, c and
xanthophylls
2. They vary in color from olive green to
various shades of brown
3. They are found in mainly in marine habitats
4. They don’t have unicellular members in this
class
15. PHAEOPHYCEAE- Brown algae
Pigments
They show great variation in size and form
Source: wikepedia, Biodiversity of central coast, All posters.com.
ECTOCARPUS MACROCYSTIS LAMINARIA
16. LUMINARIA THALLUS STRUCTURE
Hold fast helps in
anchor
Stipe: Has
strengthening tissues
and tube like cells to
transport the food
Blade: Phtotosynthetic
organ
PHAEOPHYCEAE
Brown algae
LAMINARIA Source: Meida store house, fiser man voice
Macrocystis have Pneumatocysts
17. PHAEOPHYCEAE
Brown algae
Cell wall of their cells is covered by a gummy or
gelatinous coating of algin or alginic acid.
It is a water retaining material so that the algal cell
will not dry up during low tide.
Alginic acid is extracted commercially and used as
an industrial thickening agent in food
The reserve food are stored as complex
carbohydrate such as laminarin and as a mannitol
Porphyra , Laminaria and Sargassum are used as
food.
21. Red colour is due to the predominace r-
phycoerythrin
Other pigments present: chlorophylla, d,
carotenoids and phycocyanin
Majority of the red algae are marine with greater
concentrations found in the warmer areas
They occurs in both weLl lighted regions close to the
surface of water.
Pigments
RHODOPHYCEAE- RED ALGAE
22. Deep water plants have more red pigments, while
those in the intertidal may be reddish brown,
yellowish or almost black.
Pigments
RHODOPHYCEAE- RED ALGAE
Hypnea spicifera
Source: South African Seaweeds - south coast
23. Most of the red algae are multicellular
Many red algae are filamentous and have
heterotrichous thallus
Hetero= different
trichous-= trichome or filament
Heterotrichous means the presence of more than
one type of filament
Thallus
RHODOPHYCEAE- RED ALGAE
Chondracanthus corymbiferus Kappaphycus
24. Heterotrichous thallus consists of two system:
a basal prostrate system
erect branched upright system
The food is stored as floridean starch
The grain of floridean are found in the cytoplasm.
Thallus
RHODOPHYCEAE- RED ALGAE
Source: pickuki.com
Polysiphonia
27. Uses of Red algae
Agar: a jelly like substance obtained from
Gelidium and Gracilaria
Carrageenans, gelatinous extract of the
Chondrus crispus are widely used in the
food industry.
Sushi : Japanese food
Nori Japanese name for edible seaweed
species of the red algae of genus Pyropia
28. Algae- General Characteristics
They are Chlorophyll bearing , simple thalloid,
autotrophic and mainly aquatic organism
They occur in a variety of other habitats
Their form and size are highly variable
They reproduce by Vegetative , Asexual and
Sexual Method
Vegetative- Fragmentation
Asexual- by different types of spores
Sexual Method- fusion of male and female
gametes
29. Algae- General Characteristics
Algae are useful to man in a variety of ways
Atleast a half of the total Carbon di oxide on earth
is carried out by algae through photosynthesis
They form the basis of the food cycle of all aquatic
animals
Nearly 70 species of marine algae are used as
food
Water holding substances like algin obtained
from brown algae, agar and carrageenan obtained
from red algae are commercial importance
Chlorella is use in spacetravel