Algae Characteristics and Habitats

Which method of reproduction involves the fusion of two gametes that are dissimilar in size?

Which type of algae form massive plant bodies in marine environments?

What is the most common type of spore produced during asexual reproduction in algae?

In what way do algae contribute significantly to the environment?

Which organism forms an association with algae to create lichen?

What type of organisms are algae in terms of their feeding autonomy?

Why are marine algae considered of paramount importance in aquatic ecosystems?

Which algae is known for producing hydrocolloids like algin and carrageen used commercially?

What commercial product is obtained from Gelidium and Gracilaria algae for various purposes including in ice-creams?

Which class do marine algae like Porphyra, Laminaria, and Sargassum belong to?

What is the role of Chlorella in space travel according to the text?

Characteristics of Algae

Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic organisms
They occur in a variety of habitats, including freshwater, marine, moist stones, soils, and wood
Algae can be found in association with fungi (lichen) and animals (e.g., on sloth bears)

Structure and Size

The form and size of algae are highly variable
Colonial forms include Volvox, while filamentous forms include Ulothrix and Spirogyra
Some marine forms, such as kelps, form massive plant bodies

Reproduction

Algae reproduce by vegetative, asexual, and sexual methods
Vegetative reproduction occurs through fragmentation, with each fragment developing into a thallus
Asexual reproduction involves the production of spores, such as zoospores, which are flagellated and motile
Sexual reproduction involves the fusion of two gametes, which can be isogamous, anisogamous, or oogamous

Importance of Algae

Algae are responsible for at least half of the total carbon dioxide fixation on earth through photosynthesis
They increase the level of dissolved oxygen in their immediate environment
Algae are primary producers of energy-rich compounds, forming the basis of aquatic food cycles
Many species of algae are used as food, with 70 species of marine algae being consumed
Certain algae produce hydrocolloids, such as algin and carrageen, which are used commercially
Agar, obtained from Gelidium and Gracilaria, is used to grow microbes and in food products
Chlorella, a unicellular alga, is used as a food supplement and is rich in proteins

Classification

Algae are divided into three main classes: Chlorophyceae, Phaeophyceae, and Rhodophyceae

Explore the key characteristics and diverse habitats of algae, including their occurrence in aquatic environments, moist stones, soils, and symbiotic relationships with fungi and animals. Learn about the variability in form and size of algae, from colonial to filamentous forms.