2. General Characters
• Phycology-The branch of science which deals with the
study of algae
• The word Phycology is derived from two words Phykos-
Sea weeds and logos-discourse
• Phycologist- A Scientist who studies different aspects of
algae
• Algae-It is a group of most primitive organisms with
simple thalloid plant body.
• They are autotrophic,o2 evolving green plants
• 90% of the oxygen comes from these simple plants
• They can be unicellular or multicellular
• They show wide variation in their morphology , pigments
and other metabolic products
• They bear unicellular or multicellular sex organs
• They differ in their life histories as well
3. Distribution and Habitat
• Includes 30,000 species distributed world-wide
• They are found growing in a wide variety of habitats
• They are ubiquitous and cosmopolitan
• Predominantly aquatic , could be terrestrial
• Depending upon habitat divided into 3 categories
• Aquatic habitat
• Terrestrial habitat
• Special habitat
5. Habitat
• Aquatic habitat-They occur in fresh water aquatic habitats and in
marine habitat they are grouped as
• Phyto planktons-Plants growing and covering the surface of water
body , move on the mercy of the water currents , color of the water
changes due to the colour of the of water blooms example Chlorella,
volvox, Chlamydomonas
• Benthos-All the bottom dwelling organisms both the plants and
animals , Algae growing attached to the bottom of the water reservoir
are called benthophytes , forms growing at the bottom of the soil-
epipellic, those which are attached to the rocks and stones- epilithic
7. Terrestrial Algae
• Algae grow in the moist and well aerated soil-Edaphophytes
• They grow on the surface of the soil-Saprophytes-Vaucheria
• Some can grow below the surface of the soil-Cryptophytes-Oscillatoria
Vaucheria Oscillatoria
8. Special Habitats
• Thermal Algae-They grow in hot water springs with a temperature ranging
from70-85°C,Example-Phormidium
• Cryophytes-Algae growing in the polar regions on ice and Snow-Chlamydomonas
• Epiphytes-Algae growing on the surface of other plant parts Oedogonium
• Surface of the Angiosperms leaves-Epiphyllophytes
• On the barks of Angiosperms-Epiphloeophytes
• Endophytes-Algae grow within the tissues of the other plants-Anabaena growing
inside Azolla
• Epizoophytes-Algae growing on the body of other animals-Cladophora on the
snails
• Endozoophytes-Algae growing inside the body of the animals-Chlorella within the
tissues of Hydra
11. Special Habitats
• Symbiotic Algae- Algae growing in association with the plants in which both are
benefitted from each other like Nostoc , Anabaena, Lichens
• Parasitic Algae-Algae growing as parasites on other plants- Cephaleuros
Symbiotic Algae-Lichens
Parasitic Algae-Cephaleuros
13. Range of Thallus Structure
• Unicellular thallus- Single celled organism-Chlamydomonas
• Multicellular thallus- Organisms made of large no of cells-Volvox
• Palmelloid form- Palm shaped thallus-Tetraspora
• Coenobial form- A colony having fixed no of cells-Volvox
• Dendroid form- A tree shaped thallus-Ecballocystis
• Siphonaceous form- Siphon shaped thallusVaucheria
• Filamentous form- Cylindrical , elongated thallus- Oedogonium
• Foliaceous form-leaf shaped thallus - Sargassum
14. Structure of A Typical Eukaryotic Cell
Typical Algal Cell
21. Asexual Reproduction
• Asexual reproduction takes by formation of spores which are haploid and formed
in special cells-sporangium
• Different types of spores formed are-
• Autospore
• Hypnospore
• Endospore
• Exospore
• Nannocytes
• Monospore
• Akinete
23. Sexual Reproduction
• Sexual Reproduction in Algae- The sexual reproduction
takes place by formation of gametes
• The gametes are of (+) and(-) strain
• The sexual reproduction is of three types
• Isogamy
• Anisogamy
• Oogamy
• Isogamy-When the fusing gametes are of the same shape
size and morphology
• Anisogamy-When the fusing gametes are of different
shape size and morphology
• Oogamy-When the male gamete is motile and the female
gamete is non motile ,male gamete swims and reaches
the female gamete