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Algae

  1. 1. Noakhali Science & Technology University Name:Morsheda Nur Tisha Department Of Education,Year- 2,Term-1
  2. 2. Unit 1:Phycology Learning outcomes • At the end of this unit learners will be able to: a.recognize major groups of algal genera b.understand details about phytoplankton c.explain the role of algae in different aspects • Content: • Classification of Algae based on pigments,stored products,chloplasts & flagella • Life history,general characteristics,ecology & economic importance of major algal groups- Cyanophyta,Cholorophyta,Rhodophyta,Euglenophyta ,Phaeophyta & Bacilllariophyta. • Fresh water & marine phytoplankton with their biological importance • Importance of Algae as- a.primary food producer b.producer of water bloom c.indicator of water condition d.source of food,medicine,fodder e.other economic & industrial products
  3. 3. What is Phycology • Phycology is the scientific study of algae. Also known as algology , phycology is a branch of life science and often is regarded as a subdiscipline of botany .
  4. 4. Algae -Algae is an autotrophic plant which prepare food by photosynthesis. • Characteristics: • Algae are autotrophic,diverse group of eukaryotic organisms, ranging from unicellular to multicellular forms. • Aquatic (fresh water and marine) and terrestrial environment. • They also occur in moist stones, soils, wood, on snow and on ice. • On the basis of their colours 4 groups were • recognised :- • 1. Myxophyceae or Cyanophyceae (Blue green • algae) • 2. Chlorophyceae (Green algae) • 3. Phaeophyceae (Brown algae) • 4. Rhodophyceae (Red algae)
  5. 5. QS:
  6. 6. Reproduction in Algae • Algae reproduced by 3 methods: 1:Vegetative reproduction:Cell division,fission,fragmention,hormogo nia,formation of adventitious branches,tubers,buddings etc.are the important vegetative reproduction in algae 2:Asexual reproduction involves the production of a motile spore.Zoospore,aplanospore,hypnosp ore,tetraspore,autospore,akinetes etc are the important spore types in algae
  7. 7. 3:Sexual reproduction involves the union of gametes (produced individually in each parent through meiosis).Autogamyhologamy,is ogamy,anisogamy & oogamy are the different types of sexual reproduction of alage
  8. 8. Algal bloom • Algae, in the form of algal blooms, get a bad rap for creating toxic conditions in oceans and lakes. • Algal blooms refers to the uncontrolled growth of certain microalgae, which in turn leads to the production of toxins, disruption of the natural aquatic ecosystems. • The blooms take on the colours of the algae contained within them. • The main toxin producers in oceans are certain dinoflagellates and diatoms. In freshwaters, cyanobacteria are the main toxin producers. • The main cause of algal blooms is a phenomenon called nutrient pollution. With nutrient pollution, there is an excess of nitrogen and phosphorus, which can push algae toward uncontrolled growth. The phenomenon is caused by the fertilizers we use in agriculture and animal manure
  9. 9. Economical importance Positive impacts 1. At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis. 2. Major component in aquatic food chain as primary producers. 3. Porphyra, Laminaria and Sargassum are used as food. 4. Algin (brown algae) and carrageen (red algae) are used as hydrocolloids, which is a fibrous structure holds water and used to transport seedling. 5. Agar is used as commercial products. 6. Gelidium, Graularia are used to grow microbes, make ice creams and jellies. 7. Chlorella and Spirullina are rich in proteins and used as food supplements. Negative impacts 1.Fish & other marine animals death- loss of money & food sources. 2.Toxic algae bring infections up the food chain which may result in death or diseases. 3.Algal blooms can deolete the oxygen & block the sunlight that other organisms need to live.

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