Algae bsc 1

algae general characters

1. ALGAE General Characters Kamaljit Sidhu Associate professor Department of Botany KCW , Civil lines Ludhiana

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-I t is a group of most primitive organisms with simple thalloid plant body. They are autotrophic,o 2 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

4. 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

6. Aquatic Algae Phytoplankton- Volvox Benthophytes-Chara

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

9. Special Habitats Thermal Algae- Phormidium Cryophytes- Chlamydomonas Epiphytes- Oedogonium Endophytes-Nostoc in Anthoceros

10. Special Habitats Epizoophytic Algae Endozoophytic Algae

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

12. Range of Thallus Structure

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

15. Structure Of Flagella

16. Pigments in Algae

17. Pigments in Algae Types of pigments in algae-3 types Chlorophylls Carotenoids Phycobilins Chlorophylls- 5 types- chl a chl b chl c chl d chl e - chl a widely distributed in all the algae Carotenoids- 2 types-carotenes and xanthophylls Phycobilins- Acessory pigments-3 types- phycocyanin , phycoethyrin and allophycocyanin

18. Pigments in Algae

19. Reproduction in Algae

20. Types of Vegetative Reproduction

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

22. Types of Asexual reproduction In Algae

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