[Biology Class Notes] on Seaweed Pdf for Exam

Seaweed is also known as sea vegetables are a type of algae that grow in the sea. It is mainly formed due to the accumulation of shallow water or thick growth on the rocky outskirts of the shores. Along the coastlines of the sea, the seaweed depicts a clear established zonation where the water’s depth may be 50 meters or less. The oceanic fauna is the primary consumer of this plant type. The seaweeds are anchored deep within the sea bottom with a root-like structure called the holdfasts, whose function is solely attachment. However, unlike most other plants its root doesn’t offer nutrient extraction. Generally, seaweeds nutrition content is relatively high and comes in colour variations of green, red, brown, and black. Moreover, there are many species of edible seaweeds while others hold commercial significance for humans. 

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Place of Origin of Seaweed

Seaweeds are typically plant-like stuff that washes along the shorelines. Seaweeds are discovered mainly along with the coastline belts all over the world in different climatic zones from the warm tropics to the icy polar regions. There are several species of seaweed and some are even sustaining the harsh conditions. Mainly, the naturally existing seaweeds are at a threat from human activities. For instance, the mechanical dredging of these species has brought consequential damage to the resources and their dependent fisheries. Also, there are several species of seaweed some growing near the high water mark exposed to the open air. These differ from the species that are discovered at the low levels where there is little or no exposure to light. 

Solved Questions and Answers 

1. What are Red Seaweeds?

Ans: The red seaweeds are typically the red algae that have a scientific name Rhodophyta and they belong to the class Rhodophyceae. These are distinctive species of seaweeds that typically originate in freshwater lakes and are one of the oldest types of eukaryotic algae. There is the presence of different pigments like chlorophyll A, phycoerythrin, and phycocyanin which imparts the red tinge in this seaweed. Red algae is an important part of our ecosystem and these are edible seaweeds. They are food for different fishes, crustaceans, and even humans. The red algae or seaweed is rich in nutrients like calcium and is also used in manufacturing vitamin supplements. 

2. Write About the Brown Algae?

Ans: The brown algae belong to the class Phaeophyceae that prevalently exists in different seaweeds including kelps and fucus. The kelps are mainly the largest algae with certain species like Macrocystis and Nereocystis found respectively in Pacific and Antarctic regions exceeding 33 meters in length. Another kelp, Laminaria is widespread on Atlantic and Pacific coasts. Sargassum is commonly known as gulfweed is a free-floating plant species in the Sargasso Sea and Gulf Stream. Rockweed is another significant brown algae used in cosmetics and foods.

3. State the Commercial Significance of Seaweeds?

Ans: Seaweeds have several commercial benefits and these are elaborated below:

• Edible seaweeds are healthy for consumption as they are rich in vitamins, minerals, and nutrients. These can be even consumed as dried seaweed. 

• Some of them even have significant medical benefits.

• There are certain seaweeds that contain powerful cancer-fighting agents.  

• Some seaweed species have anti-microbial and anti-inflammatory properties. 

• Seaweeds are effective binding agents or emulsifiers. This is why they are used in commercial commodities like toothpaste, softeners, and fruit jellies. 

• Seaweeds are used in many organic cosmetics and skincare products. 

4. What is the Importance of Seaweed Farming?

Ans: Seaweed farming has several advantages for the economy of the country. The details are explained below:

• It is a major weapon against rising sea pollution and helps mitigate the effects of CO₂, the contributor to global warming. 

• It provides occupation to the people residing near the shorelines and coastal areas.

• It provides a constant supply of raw materials to the industries dependent upon the seaweeds.

• The cultivation of seaweed food is also environmentally friendly. 

Did You Know

The dried seaweed is typically edible and used in Japanese cuisine in wrapping rolls and sushi. Another one is the roasted seaweed also used in the cooking preparation of sashimi and sushi.