This document provides an overview of algae. Algae are plantlike protists that belong to the kingdom Protista and perform photosynthesis. They range in size from microscopic single-celled organisms to large seaweeds hundreds of feet long. Algae have chloroplasts and produce carbohydrates through photosynthesis. They are classified into four main types based on their structure: unicellular algae consisting of a single cell, multicellular algae with complex thalli, colonial algae with groups of coordinated cells, and filamentous algae with slender filament-shaped thalli of rows of cells. Phytoplankton, mainly unicellular algae, produce around half of the world

1. Algae
Chpter-7 Section-2

2. Objectives
• General information about algae.
• Explain the general characteristics of algae.
• Describe the various body structure of algae.

3. What is algae?
 Algae are plantlike organisms
 Belong to kingdom Protista
 They are doing photosynthesis
 The body portion of an algae is called thallus

4. Characteristics
• Algae are a diverse group of Protists.
• Range from microscopic single-cell organisms to a
large seaweeds that may be hundreds of feet long.
• Unlike protozoa algae are autotrophic protists.
• They have chloroplasts and produce their own
carbohydrates by photosynthesis
• Most of algae are aquatic and have flagella at
some point of their life-cycle
• In addition algae cells often contain pyrenoids.

5. structure
• Based on the structure of algae 4 types are
recognized.
1. Unicellular algae
2. Multicellular algae
3. Colonial algae
4. Filamentous algae

6. Unicellular algae
• Consist of one cell
• Most of them aquatic that compose the
phytoplankton.
• Phytoplankton: a population of photosynthetic
organisms.

7. phytoplankton
• phytoplankton produce almost half of the
world carbohydrates
• Provide huge amount of nutrients for aquatic
organism.
• Also produce oxsygen

8. Multicellular algae
• Often have a large and complex thallus
• For example Ulva

9. Colonial algae
• Have a structure that consist of groups of cells
Acting in a coordinated manner.
For example: Volvox

10. Filamentous algae
• Have a slender, rod-shaped thallus composed
of rows of cells.
for example: Spirogyra

11. Next lesson
Reproduction
Classification