Algae
Anjitha
Algae are photosynthetic organisms that contain photosynthetic pigments like chlorophyll. However, they lack true roots, leaves, and stems, characteristic of vascular plants. Algae exist in environments from oceans, rivers, and lakes to ponds, brackish waters etc. Algae are usually green in colour, but they can be found in a variety of different colours.
Algae are very useful to man it helps in carbon dioxide fixation. They are the important primary producers of energy-rich compounds which form the basis of the food cycles of all aquatic animals. They are the primary food source of many organisms. They are calcium rich and used in vitamin supplements
Algal cells are eukaryotic. Algae can photosynthesize like plants, and they possess specialized structures and cell organelles like centrioles and flagella, found only in animals.
- Algae are photosynthetic organisms
- Algae can be unicellular or multicellular organisms
- Algae lack a well-defined body because structures like roots, stems, or leaves are absent
- Reproduction in algae occurs in both sexual and asexual forms. Asexual reproduction occurs through spore formation.
- Algae are free-living, and some can form a symbiotic relationships with other organisms
Algae can act as an indicator of the degree of worsening of water quality, and many algal indicators have been used to assess environmental status. Study of algae is known as phycology.
Algaes exist in various forms they are green algae, red algae, brown algae, etc.
Rhodophyceae
It is also called Red alge, it is found in marine as well as freshwater ecosystems. The pigments phycoerythrin and phycocyanin are the reason for the characteristic red colouration of the algae. Stored food is Floridean starch. It existed in freshwater, brackish water, and salt water. Normally found in coral reefs and tide pools.
Eg: Gracilaria and gelidium
Chlorophyceae
It is commonly called green algae. The body of the plant may be unicellular, filamentous or colonial. They are usually grass green in colour due to the presence of pigments chlorophyll a and b. The stored food material is starch.
Eg: Chlamydomonas, Vivox, Ulothrix, and Spirogyra
Phaeophyceae
Phaeophyceae members are commonly called brown algae. They are found in marine habitats. The major pigment is fucoxanthin. Stored food has complex carbohydrates, which may be laminarin or mannitol. The vegetative cells have a cellulose wall usually covered on the outside by a gelatinous coating of algin.
Eg: Laminaria, Sargassum, Fucus.
Xanthophyta
Xanthophyta members are commonly known as yellow-green algae. They are found generally in fresh water. The major pigment is β-carotene and carotenoid diadinoxanthin.
They store food as oil, fat, etc.
Eg: Voucheria
Read more : Dragon curve
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Gracilaria and gelidium
Brown algae
Floridean starch
Chlorophyceae