Question

Which algae is commonly called as pond silk or pond scum?
a. Volvox
b. Chlamydomonas
c. Euglena
d. Spirogyra

Answer 1

Hint: Any of various algae or cyanobacteria. Algae are a diverse group of aquatic organisms and include species from multiple distinct clades. It is a mass of tangled filaments of algae or cyanobacteria in stagnant waters, the mass of algae forms a green film on the surface of stagnant water. The species reproduce both asexually and sexually.

Complete answer:
The algae can be divided into different groups based on the morphological state of a vegetative or growing state. Every group of algae has different functions. Algae can perform photosynthesis.

- Algae are a diverse group of aquatic organisms that can perform photosynthesis
- It is a polyphyletic group that includes species from multiple distinct clades.
- In large, macroscopic algae, groups of cells are specialized for specific functions, such as anchorage, transport, photosynthesis, and reproductions
- The algae can be divided into different types based on the morphology of their vegetative or growing state.
- Algae are ubiquitous throughout the world and can be categorized ecologically by their habitats.
- Algae form organic food molecules from carbon dioxide and water through the process of photosynthesis, in which they capture energy from sunlight.
- Spirogyra, (genus Spirogyra), found in a freshwater environment around the world.
- They have spiral chloroplasts, consisting of thin unbranched chains of cylindrical cells. They form masses that float near the surface of streams.
- Each cell of the filaments features a large central vacuole, within which the nucleus is suspended by fine strands of cytoplasm.
- The cell wall consists of an inner layer of cellulose and an outer layer of pectin, which is responsible for the slippery texture of the algae.
- Spirogyra species reproduce both sexually and asexually. Asexual reproduction occurs by simple fragmentation of the filaments whereas sexual occurs by a process called conjugation
- Therefore, spirogyra is known as pond silk or pond scum.

Hence, the correct answer is option (D).

Additional information:
Volvox can be found in ponds, puddles, and bodies of still freshwater throughout the world. They are autotrophs contributing to the production of oxygen and serve as food for several aquatic organisms.
Chlamydomonas is a unicellular chlorophyte that can use both autotrophic and heterotrophic metabolic pathways, it contains ion channels that are directly activated by light.
Euglena is found in moist soils and lives in fresh and brackish water rich in organic matter.

Note: The filamentous algae genus Spirogyra known as water-silk, mermaid's tresses, or pond scum, are a large presence of the unbranched algae often indicates the nutrient enrichment of freshwater bodies. Spirogyra is commonly referred to as pond silk, water silk, pond scum, or mermaid's trees because of their bright green silky appearance. It is unicellular freshwater algae that occur in large free-floating submerged mats and slow-moving streams.