Taxonomic classification of algae is based upon the same rules that are used for the classification of land plants. Microscopic research has shown differences in the features of algae which contributes to another method of their classification. Various features that differentiate various types of algae are: organelle structure, flagellar apparatus, and cell division process. Division-level classification (kingdom-level classification) is negligible for algae. Some scientists place class like xanthophycaecae, bacillophyceae, in division Chromophyta, whereas some scientists place each class in the division: xanthophyte, bacillophyta.
Different algae have different requirements. Hence, several essential factors such as water, carbon dioxide, minerals and light play important roles in the cultivation of the algae.
The habitat of algae can be anywhere and everywhere. Algae are the most robust organism in terms of habitat, as they can grow in a wide range of conditions. Algae can be found in both environments: terrestrial and aquatic. Moreover, it’s very common to find algae in moist regions than dry ones, as algae do not have vascular tissues and other adaptations for living on land. Yet algae can be found in any and every part of the world. The examples include snails, turtles, worms, rotifers, worms, alligators, three-toed sloths, aquatic ferns, freshwater sponge, aquatic plants, on and inside water plants.
Algae are comprised of two types of cell: eukaryotic or prokaryotic cell. These are cells with nuclei and organelles. The functional systems of algae are plastids, which are bodies with chlorophyll and carry out photosynthesis. Some have only Chlorophyll A, some A and B, A and C etc.the primary composition of algae is made up of proteins, carbohydrates, fats, nucleic acids, in varying proportion. All types of algae found completely comprise of the following, in varying proportions: Proteins, Carbohydrates, Fats and Nucleic Acids. While the percentages vary with the type of algae, types of algae are there, some of them comprised up to 40% of their overall mass by fatty acids. This fatty acid from the algae can be extracted and converted into biodiesel. Algal-oil is very high in unsaturated fatty (UFA) acids which include Arachidonic acid (AA), Eicospentaenoic acid (EPA), Docasahexaenoic acid (DHA), Gamma-linolenic acid (GLA), Linoleic acid (LA) etc.
Four main patterns of lifecycle in the algae are:
Algae are used in various fields such as in the food industry as a food supplement, in waste-water purification as a bio-filter, in laboratory research system, in space biotechnology, etc. Algae are commercially cultivated for pharmaceuticals, nutraceuticals, cosmetics and aquaculture purpose. It is also used as a fuel source, stabilizing agent and as a fertilizer.