Protista Photosynthetic Dinoflagellates Euglenoids

Protista Photosynthetic Dinoflagellates Euglenoids

Introduction: In this chapter, Protista Photosynthetic Dinoflagellates Euglenoids we will discuss in detail. Kingdom Protista Proposed by Ernest Haeckel. Protists are ancestors of eukaryotic organisms. They are mostly found in the form of Plankton.

• Microscopic organisms and live in aquatic.
• Also lives in the body of animals as parasites.

Structure of Protist:

• Eukaryotic, having plasmalemma, pellicle, contains mitochondria, 80S ribosomes, Golgi complex, centrioles, chloroplast, cilia and flagella, nucleus, nucleolus, etc.

Image 1: Euglena

Locomotion of Protists:

• Isochronic and Metachronic coordination help in ciliary locomotion. e.g. Paramecium.
• Protists have pseudopodia which helps in locomotion. Lobo podia present in Amoeba, Filopodia present in Euglypha, Axopodia present in Actinophrys, and Reticulopodia present in Globigerina.
• Wave-like contraction is found in sporozoans, euglenoids, etc.

Nutrition of Protists:

• Prepare their food from photosynthetic activity.
• Amoeba ingests the food.
• Slime moulds absorb the food by saprotrophic.
• Plasmodium obtains its food from other organisms as a parasite.
• Trichonympha and Lophomonas act as symbionts and prepare the food.

Reproduction in Protists: Reproduce as sexual and asexual methods.

a) Sexual reproduction: By meiosis and fertilization.

1) Syngamy: formation of diploid zygotes.

• Isogamy: fusion of similar gametes e.g. Monocystis
• Anisogamy: when different gametes are fuse e.g. Ceratium
• Oogamy: When non-motile and motile is fuse e.g. Plasmodium

Life cycle showing gametic meiosis

2) Conjugation: When two individuals exchange their haploid pronuclei. e.g. Paramecium

b) Asexual reproduction: When young ones produce involvement of the single parent.

• Binary fission: Division of parent body into two daughter cells, e.g. Amoeba, Euglena, etc.
• Multiple fission: Division of parent body into many individuals, e.g. Amoeba and plasmodium
• Budding: when new outgrowth is developed on the parent, e.g. Arcella 

SEE ALSO: Biological Classification

Protista Protozoan Plasmodium

A) PHOTOSYNTHETIC PROTISTS:

1) Dinoflagellates:

• Some live in fresh water and marine.
• Gonyaulax causes red tide in the sea.
• Noctiluca, Gonyaulax, etc. show bioluminescence.
• The mode of nutrition is photosynthetic.
• Example: Triceratium, Cymbella, Navicula, etc.

Structure of Dinoflagellates:

• Found in Yellow, blue, brown, and red colors.
• Unicellular motile and biflagellate.
• A rigid coat is a theca and it contains two grooves i.e. Sulcus and annulus.
• A transverse flagellum and other is longitudinal.
• Contains large size nucleus, plastids, mucilage bodies, eyespots, and trichocysts.

Image 2: Gonyaulax

Reproduction in Dinoflagellates:

• Isogamous and isogamous sexual reproduction occur in some dinoflagellates.
• Asexual reproduction occurs by cell division.

Examples of Dinoflagellates:

• Ceratium: found in fresh water and marine and a large number of chromatophores are present.
• Noctiluca: Found in temperate and tropical areas, Shows bioluminescence and long tentacle work as flagellum.
• Gonyaulax catenella: It produces toxins and kills other aquatic organisms.

2) CHRYSOPHYTES: Diatoms

• Mostly aquatic, free-floating, show gliding by mucilage.

Structure of Diatoms:

• The outer siliceous shell is Frustule and made of epitheca and hypotheca.
• They are microscopic, colored, and do not possess flagella.
• Symmetry is pennate and centric.
• Central vacuole, large nucleus, chloroplast, etc. present.
• Fucoxanthin provides a brown color.

Image 3: Diatoms

Reproduction in Diatoms:

• Fertilization form a zygote by sexual reproduction.
• Multiply by binary fission.

Importance of Diatoms:

• Diatomite is used in the filtration of alcohols, syrups, and sugar.
• Diatomite is used in paints for the increment of visibility in darkness.
• Diatomite is used in toothpaste.
• Diatomite is used in metal polishes.
• Diatoms help in pollution indicators.
• Diatomite use as an industrial catalyst.

3) EUGLENOIDS: Characteristics of Euglenoids:

• They are unicellular flagellates.
• Found in freshwater.
• Movement is the contraction of the body.
• The mode of nutrition is photoautotrophic and saprobic.

Structure of Euglenoids:

• The outermost covering is the pellicle which contains elastic protein, lipids, and carbohydrates.
• Euglenoids have one short and one long flagellum.
• The contractile vacuole is present.
• Chlorophyll a and Chlorophyll b are photosynthetic pigments.
• A large nucleus is present.

Reproduction: Euglenoids multiply by longitudinal binary fission during favorable conditions.

EUGLENA: Found in freshwater bodies and freely solitary. Unicellular flagellate. Chloroplasts are many in numbers. Photoreceptors are present. Osmoregulation occurs in the vacuole.

B) CONSUMER-DECOMPOSER PROTISTS (Slime moulds)

Characteristics of Slime moulds:

• Known as Fungus-animals.
• Contains a plasma membrane.
• The mode of nutrition is phagotrophic.
• Chlorophyll is absent.
• Reproduction is sexual and asexual.

Acellular Slime moulds: (plasmodial slime moulds)

• Found on dead and decaying vegetation.
• The freely thalloid body is the plasmodium.
• Have several branches called veins.
• Structure act for perennation.
• The life cycle occurs in Sporangia, spores, germination and sexual reproduction, and the Formation of plasmodium.

Cellular Slime moulds: (Acrasiomycetes)

• Found in humus containing damp.
• They are uninucleate and amoeba-like cells.
• Phagotrophic in nutrition.
• Life cycle occurs Pseudo plasmodium, sporangium, spores, and sexual reproduction.

The life cycle of cellular Slime mould

Conclusion: Kingdom Protista is divided into Photosynthetic, Consumer-Decomposer, and Protozoan Protists. Hence Protista Photosynthetic Dinoflagellates Euglenoids are discussed here and the rest part will discuss in the next chapter.

In this chapter, Protista Photosynthetic Dinoflagellates Euglenoids above the information is completed in detail with images.