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Algae refers to a wide range of eukaryotic organisms, from single-celled microalgae to multicellular organisms like gigantic kelp. Algae are plant-like organisms that are split into two groups: photosynthetic algae and aquatic algae. Although it resembles a plant, it lacks genuine roots, stems, leaves, and vascular tissue, yet it does have basic reproductive components. The majority of the algae seen are microscopic, however, some are rather huge, such as marine seaweeds that may grow up to 50 metres in length.
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Key Takeaways- Thallus, Vascular Tissue, Seaweeds, phylogenetic, Gracilaria, Gelidium, Agar-Agar
What is Algae?
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Alga is a large and diverse group including eukaryotic, photosynthetic life forms. They do not share a common ancestor and are not related to each other (polyphyletic). These are simple living organisms that contain chlorophyll. They are the most primitive producers in a food chain. They come in two forms: multicellular and single-celled. Algae are generally aquatic, with a thalloid structure that is difficult to distinguish. Freshwater, sea, moist stones, wood, and even soil are all places where algae can be found. A mutualistic relationship exists between fungi and algae, resulting in lichens, a completely different organism. They provide crude oil as well as a variety of pharmaceutical and industrial products used by humans. Algae grows in a watery environment and they are similar to photosynthetic organisms and land plants.
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Characteristics of Algae
Following are the Characteristics of Algae:
- Algae are autotrophic thalloid plant bodies that contain chlorophyll.
- Almost all algae are found in water.
- The plant body can range in size from a single cell to a massive, strong multicellular structure.
- The multicellular complex thalli lacks vascular tissue and shows little tissue differentiation.
- In most situations, the sex organs are unicellular, but when they are multicellular, all of the cells are fertile, and the entire complex is unprotected.
- The zygote can continue to develop through mitosis or meiosis, but not through the development of an embryo.
- Plants have a characteristic generational alternation. Both gametophyte and sporophyte generations are autonomous when both are present in the life cycle.
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Types of Algae
There are three types of Algae:
Chlorophyceae
The Chlorophyceae are a family of green algae with ultrastructural morphology that distinguishes them. They are usually green because the pigments chlorophyll a and chlorophyll b predominate. Some green algae can store food in the form of oil droplets.
Phaeophyceae
Brown algae is another name for them, and they're typically found in the sea. Chlorophyll-a, c, carotenoids, and xanthophyll are pigments found in them. Phaeophyceae members store food as mannitol. The main end product is mannitol, which is the most common form of carbon storage in these algae.
Rhodophyceae
They are commonly referred to as red algae because they contain r-phycoerythrin, a water-soluble red pigment. The r-phycoerythrin, on the other hand, is plentiful enough to hide the chlorophyll a, giving the plant its characteristic red hue. The bulk of the members are marine, while the rest are freshwater.
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Properties of Algae
Algae have a wide range of requirements. As a result, various vital variables such as water, carbon dioxide, minerals, and light play an important part in the algae's growth.
- Size: Chlamydomonas, for example, is a single-celled organism. Some algae, such as Volvox, live in colonies. Ulothrix and Spirogyra, are filamentous algae. Kelps are a type of marine organism that produces gigantic plant bodies.
- Reproduction: Algae reproduce in a variety of ways, including vegetative, asexual, and sexual reproduction.
- Vegetative Reproduction: Fragmentation is used in vegetative reproduction. A thallus separates into multiple fragments during vegetative reproduction, and each fragment develops into a thallus.
- Asexual Reproduction: Different types of spores are used in algae to reproduce asexually. The most prevalent sort of spore is zoospores. The zoospores are motile because they are flagellated. On germination, they produce new plants.
- Chemical Composition of Algae: There are two types of cells in algae: eukaryotic and prokaryotic cells. These are nucleated cells with organelles. Algae's functional systems are plastids, which are chlorophyll-containing bodies that perform photosynthesis. Some have only Chlorophyll A, whereas others have A and B, A and C, and so on. Proteins, carbohydrates, lipids, and nucleic acids, in variable proportions, make up the fundamental component of algae. Proteins, Carbohydrates, Fats, and Nucleic Acids are all present in variable quantities in all forms of algae discovered.
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Importance of Algae
Algae, according to some scientists, produce half of the oxygen on the planet. And algae's contribution to oxygen production is by far the most crucial. They are a crude oil source, as stated at the beginning. These algae biofuels have the potential to replace fossil fuels. Algae also serves an important part in maintaining atmospheric carbon dioxide levels and utilising them effectively. Algae is also used in the food sector. Gelidium and Gracilaria produce agar, which is used to make ice cream and jellies. Chlorella and Spirulina are two more algae-based nutritional supplements that are widely used.
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Life Cycle of Algae
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In algae, there are four primary lifecycle patterns:
Haplontic Life Cycle
A gametophyte is a type of plant. The haploid gametes are produced by the gametophytic plant. The gametes join together to produce a diploid zygote. As a result, diploid denotes the sporophytic (diploid) phase of their lifecycle. This lifetime, also known as the monogenic lifecycle, is active in the majority of classes.
Diplontic Life Cycle
A sporophyte is the plant body. The gametophytic stage is represented by the sex organs, which create gamete through meiosis. The gametes combine and fertilise to generate a zygote very quickly. Meiosis does not occur in the zygote. The zygote's sole function is to produce new sporophytic plant bodies.
Haplodiplontic Life Cycle
Both the diploid and haploid phases are equally present and prominent in this type, which is manifested by two vegetative individuals. There is just a variation in terms of chromosomal numbers and functions between the two. The haploid (gametophytic stage) reproduces sexually, whereas the diploid (sporophytic stage) reproduces asexually. There are two sorts of life cycles: isomorphic (homologous) and heteromorphic (heterologous).
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Points to Remember
Following are some important points:
- Algae is responsible for over half of all carbon fixation on the planet. As a result, they are among the world's largest producers, particularly in aquatic habitats.
- Hydrocolloids are produced in significant quantities by some marine brown and red algae. Hydrocolloids are commercially used water-holding compounds.
- Harmful algae and cyanobacteria can create toxins that can cause illness in humans and animals
- In laboratories, agar, which is made from Gelidium and Gracilaria, is employed as a culture medium. It's also used in the production of ice cream and jelly.
- Even during space travel, chlorella and spirulina are utilised as nutritional supplements.
- Algae or their spores can be found in a wide range of settings, including freshwater, marine water, air, soil, and other species.
Sample Questions
Ques: What do algae need to survive? (2 Marks)
Ans: Water, sunlight, carbon, and nutrients like nitrogen and phosphorus are all necessary for algae to develop. The diversity of algae implies that there are strains that can make use of practically any water supply, from saltwater to freshwater and everything in between.
Ques: What are algae helpful for? (2 Marks)
Ans: Algae are employed in a variety of industries, including the food business as a food supplement, waste-water purification as a bio-filter, laboratory research systems, and space biotechnology, to name a few. Commercially grown algae are used in medications, nutraceuticals, cosmetics, and aquaculture. It's also utilised as a fertiliser, a fuel source, and a stabilising agent.
Ques: Can algae live outside water? (2 Marks)
Ans: Algae spores can survive outside of the water and can be found on our swimsuits, towels, and pool care equipment like vacuum hoses, wall brushes, and leaf nets. Unicellular green algae from biological soil crusts in the desert may live for at least four weeks under controlled laboratory conditions (Grey et al., 2007). Desiccation-tolerant desert algae and closely related aquatic relatives were subjected to dry conditions in this study.
Ques: Is it OK to drink algae water? (2 Marks)
Ans: Gastroenteritis can be caused by drinking algae-affected water or eating food (such as fish or shellfish) that contains toxins, which can cause vomiting, diarrhoea, fevers, and headaches. The liver and neurological system may be harmed by these poisons. Harmful algae can potentially affect pets and livestock.
Ques: How do you remove algae from water? (2 Marks)
Ans: To kill the algae, use bleach. If you have an algae problem, you can kill it all together with bleach. For each gallon of water in your tank, use a quarter teaspoon. Bleach is effective at killing algae (as well as other creatures that may be lurking in your aquarium) and preventing it from returning. Chlorine also kills algae, making your water safe to drink or use for irrigation.
Ques: How can algae be harmful? (3 Marks)
Ans: Harmful algae and cyanobacteria (also known as blue-green algae) can create toxins (poisons) that can cause illness in humans and animals, as well as harm the environment. When water is warm, slow-moving, and rich in nutrients, algae and cyanobacteria can quickly grow out of control, or "bloom." Algal blooms deplete oxygen in the water and prevent sunlight from reaching fish and plants as they expand. When the algae die, the bacteria that digest the dead algae consume even more oxygen, causing more fish to perish or leave the region.
Ques: How do algae spread? (2 Marks)
Ans: Algae spores are generally transferred from one body of water to another. Spores are single reproductive cells that, in the correct conditions, can germinate and proliferate. Algae spores can be found throughout nature and are frequently dispersed by the wind and rain runoff. Asexually, through fragmentation or spread of spores, or sexually, by creating gametes that fuse during fertilization, green algae reproduce.
Ques: Are algae edible? (2 Marks)
Ans: Seaweeds are edible algae that have been consumed in numerous coastal places across the world for ages. Algae have a high nutritional value since they include complete protein, fibre, and sometimes high levels of omega-3 fatty acids (in contrast to plant food gathered on land). Many vitamins, including A, C, B1, B2, B3, and B6, as well as minerals like iodine, calcium, potassium, magnesium, and iron, are found in algae. They can be eaten raw, cooked, or dried.
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