This document provides an overview of algae, including their structure, classification, reproduction, importance, and issues like algal blooms. It discusses that algae come in various forms from single-celled to multicellular and lack true roots/leaves. Algae are broadly divided into unicellular and multicellular categories. It also summarizes Fritsch's 11 class system of algae classification based on pigments, flagella, and food storage. The document outlines that algae reproduce through asexual/vegetative and sexual means and discusses their importance in oxygen production and carbon storage, as well as issues like toxic algal blooms fueled by excess nutrients.

1. ALGAE- STRUCTURE
AND CLASSIFICATION
PRESENTED BY:-
RAJPAL CHOUDHARY
REG. NO.- 161103004
M.Sc. BIOTECHNOLOGY 1ST YEAR

2. INTRODUCTION
• The general term "algae" includes prokaryotic organisms — cyanobacteria, also known
as blue-green algae — as well as eukaryotic organisms (all other algal species).
• Algae are a diverse group of aquatic organisms that have the ability to conduct
photosynthesis.
• Algae are found in a range of aquatic habitats, both freshwater and saltwater.
• Algae are also able to survive on land. Some places where they grow are tree trunks
and animal fur.

3. STRUCTURE
• They also occur in a variety of forms and sizes. They can exist as single and
microscopic cells, they can be macroscopic and multicellular.
• Algal body, also known as thallus, lack true roots, stems and leaves, and a vascular
system to circulate water and nutrients throughout their bodies.
• It is broadly divided into two main categories:-
a) Unicellular
b) Multicellular

5. UNCELLULAR
a) Non motile:- A single non-motile cell
carrying out all essential functions of
life. Flagella is absent.
E.g.- Chlorella
b) Motile:- A single cell with flagella for
locomotion.
E.g.- Chlamydomonas Chlorella

6. MULTICELLULAR
Colony is formed by aggregation of
individual cells.
Non motile colony:- Individual cell
in the colony lacks flagella.
E.g.- Pediastrum
Pediastrum

7. Motile colony:- Individual cells
possess flagella.
E.g.- Volvox
Volvox

8. Amorphous colony:- Numerous
non motile cells are embedded in a
common mucilaginous matrix.
E.g.- Tetraspora
Tetraspora

9. Dendroid forms:- The thallus
appears as tree like under
microscope.
E.g.- Dinobryon
Dinobryon

10. Filamentous:- Cells arranged one
upon the other in a definite
sequence forming filament. Filament
may be branched or unbranched.
E.g.- Spirogyra, Cladophora
Cladophora

11. Heterotrichous form:- Presence
of more than one type of filament.
E.g.-Draparnaldiopsis
Draparnaldiopsis

12. Siphonous form:- Elongated
thallus without septation.
Multinucleate
E.g.- Vaucheria
Vaucheria

13. Parenchymatous forms:- Cell
division and associated septation leads
to the formation of a parenchymatous
body.
E.g.- Chara
Chara

14. CLASSIFICATION
• Fritsch’s Classification of Algae:
• F.E. Fritsch (1935, 1945) in his book “The Structure and Reproduction of the
Algae” proposed a system of classification of algae. He divided it into 11 classes.
His classification of algae is mainly based upon characters of pigments, flagella
and reserve food material.

15. • Eleven classes proposed by Fritsch are as follows:
• 1. Chlorophyceae
• 2. Xanthophyceae
• 3. Chrysophyceae
• 4. Bacillariophyceae
• 5. Cryptophyceae
• 6. Dinophyceae
• 7. Chloromonadineae
• 8. Euglenineae
• 9. Phaeophyceae
• 10. Rhodophyceae
• 11. Myxophyceae(Blue green algae)

16. REPRODUCTION
• Algae are capable of reproducing through asexual or vegetative methods and via
sexual reproduction.
• Asexual reproduction involves the production of a motile spore.
• Vegetative methods include simple cell division (mitosis) to produce identical
offspring and the fragmentation of a colony.
• Sexual reproduction involves the union of gametes (produced individually in each
parent through meiosis).

17. IMPORTANCE
• Probably the most important contribution of algae to our environment is the
generation of oxygen through photosynthesis.
• Algae are indispensable because they produce about half the oxygen in Earth's
atmosphere.
• Green algae, diatoms and cyanobacteria are just some of the microalgal species that
are considered good candidates for the production of biofuel.
• Algae help to keep atmospheric carbon dioxide levels stable by storing the gas in
organic materials that include oil deposits and inorganic carbonate rocks.

18. ALGAL BLOOM
• Algae, in the form of algal blooms, get a bad
rap for creating toxic conditions in oceans and
lakes.
• Algal blooms refers to the uncontrolled growth
of certain microalgae, which in turn leads to the
production of toxins, disruption of the natural
aquatic ecosystems.
• The blooms take on the colours of the algae
contained within them.

19. • The main toxin producers in oceans are certain dinoflagellates and diatoms. In
freshwaters, cyanobacteria are the main toxin producers.
• The main cause of algal blooms is a phenomenon called nutrient pollution. With
nutrient pollution, there is an excess of nitrogen and phosphorus, which can push
algae toward uncontrolled growth. The phenomenon is caused by the fertilizers
we use in agriculture and animal manure.

20. REFERENCE
• http://www.sciencedirect.com/science/article/pii/S0306261910005799
• http://www.nrcresearchpress.com/doi/abs/10.1139/b77-095
• https://dl.sciencesocieties.org/publications/jeq/abstracts/27/2/JEQ0270020261

21. THANKYOU