• Biology,  Zoology

    Phylum Cnidaria/Coelenterata

    Kingdom: Animalia Habitat: aquatic, mostly marine. Habit: solitary or colonial. Each individual is known as zooid. Symmetry: radially symmetrical Grade of organization: tissue grade of organization. Germ layer: diploblastic, outer ectoderm and inner endoderm. Mesogloea separates these two layers. The body has a single opening called hypostome surrounded by sensory tentacles. Coelom: gastrovascular cavity or coelenteron. Nematocyst: organ for capturing and paralyzing pray, present in tentacles Nutrition: holozoic Digestion is both intracellular and extracellular. Respiration and excretion are accomplished by simple diffusion. Circulatory system: absent Nervous system: poorly develop, Many forms exhibit polymorphism ie. Polyp and medusa. Polyps are sessile, asexual stage. Medusa are free swimming, sexual stage Metagenesis: asexual…

  • Biology,  Botony


    Position of Fungi During warm humid days slices of bread, chapati, leather belts or shoes, etc. develop powdery layer on them. In lawns and flower beds, mushrooms come out. These are all fungi. Fungi were earlier classified as plants without chlorophyll and without differentiation of parts into root, stem and leaves. They are now included, in a separate Kingdom Fungi. Characteristics of Fungi Fungi are multicellular eukaryotes Fungi exist as the slender thread-like filaments called hyphae. Hypha has many nuclei. Yeast, however, is single-celled. The cell walls are made of chitin A hypha may be divided into cells by partitions called septa. Septa have pores through which cytoplasm streams freely.…

  • Zoology


    Protoctista is unicellular eukaryotes. Protozoa and diatoms and algae are included in it. They have membrane-bound organelles such as nucleus with chromosomes enclosed in the nuclear membrane, mitochondria, chloroplast (in photosynthetic protoctists only), Golgi bodies and endoplasmic reticulum. Mitochondria are the respiratory organelles. Protoctists are either photosynthetic, parasitic or saprotrophic. For locomotion, protoctists may have cilia or flagella (Fig.) having 9 + 2 microtubules unlike those of bacteria, which have the 9 + 1 arrangement of microtubules. They reproduce both asexually and sexually. Some protoctists are beneficial to humans while others are harmful. Classification of Protoctista The kingdom Protoctista includes – 1. Phylum Protozoa which has the following four classes…


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