what is green algae?

A variety of algae growing on the rock

Algae are simple plants that can range from the microscopic (microalgae), to large seaweeds (macroalgae), such as giantkelp more than one hundred feet in length. Microalgae include both cyanobacteria, (similar to bacteria, and formerly called “blue-green algae”) as well as green, brown and red al-gae. (There are more varieties of microalgae, but these are the main ones.)Algae can be grown using water resources such as brackish-, sea-, and wastewater unsuitable for cultivating agricultural crops. When using wastewater, such as municipal, animal and even some industrial
runoff, they can help in its treatment and purification, while benefiting from using the nutrients present.Most microalgae grow through photosynthesis – by converting sunlight, CO2 and a few nutrients, including nitrogen and phosphorous, into material known as biomass This is called “autotrophic” growth. Other algae can grow in the dark using sugar or starch (called “heterotrophic” growth), or even combine both growth modes (called “mixotrophic” growth).Algae are very diverse and found almost everywhere on the planet. They play an important role in many ecosystems, including providing the foundation for the aquatic food chains supporting all fisheries in the oceans and inland, as well as producing about 70 percent of all the air we breathe.

IMPORTENT CHARACTERISTICS OF ALGAE

1.Algae are chlorophyll-bearing autrophic thalloid plant body.  2. Almost all the algae are aquatic. 3. The plant body may be unicellular to large robust multicellular satructure. 4. The multicellular complex thalli lack vascular tissue and also Little differentiation of tissue. 5. The sex organ are generally unicellularl but, when multicellular,all cells are fertile and in most cases the entire structure does not have any protection jacket. 6. The zygot undergoes further development either by mitosis or meiosis, but not through embryo formation. 7. Plants having distinct alternation of generation both gametophyte and sporophyte generation – when present in the life cycle are independent.

HOW MANY TYPES OF ALGAE PRESENT?

Based on habitat the algae may be categorized as: 1. Aquatic algae  2. Terrestrial algae, and  3. Algae of remarkable habitats.

Scientific classification

Domain:Eukaryota

A. Included groups

Archaeplastida a)       Chlorophyta (green algae) b)       Rhodophyta (red algae) c)       Glaucophyta        Rhizaria, Excavata a)       Chlorarachniophytes b)       Euglenids        Chromista, Alveolata a)       Heterokonts 1.       Bacillariophyceae (Diatoms) 2.       Axodine 3.       Bolidomonas 4.       Eustigmatophyceae 5.       Phaeophyceae (brown algae) 6.       Chrysophyceae (golden algae) 7.       Raphidophyceae 8.       Synurophyceae 9.       Xanthophyceae (yellow-green algae) b)       Cryptophyta c)       Dinoflagellates d)       Haptophyta

B. Excluded groups

1. Cyanobacteria
2. Plantae