Zoology for UPSC and State PSC exams
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Body wall of all the coelenterates contains special defensive structures called as stinging cells or nematocysts.Cnidocyte contains a fluid-filled membranous capsule called cnida.Help not only in defense but also in…
Occurrence in the same species of more than one type of individuals, which differ in form and function.Ensures an effective division of labour between the individuals.In coelenterates, the different individuals…
Asexual Reproduction Budding Number of individuals in colonies increases, or new colonies are formed.Archaeocytes collect at the surface and Pinacoderm bulges out to receive them.Bud grows into an adult individual.Either…
Almost all sponges have skeleton embedded in the Mesenchyme (loosely organised, mesodermal embryonic tissue which develops into connective and skeletal tissues, including blood and lymph).Supports and protects the soft body…
Distinguishing feature of Sponges is the perforation of body surface by numerous apertures for ingress and egress of water current.Water current flows through a certain system of spaces collectively forming…
Life Cycle:Man: Asexual phase: Liver schizogony. Multiple fission forming Merozoites.Erythrocytic schizogony: Second phase in RBCs. Forms gametocytes at the end.Mosquito: Sexual cycle.Gametogony: production and fusion of gametes.Sporogony: Post zygotic multiplication,…
General Features Exists in 2 forms: Leishmanial in man (vertebrate host) and Leptomonad in sandfly (invertebrate host).Whole body is covered by a pellicle.Uniflagellate. But in the Leishmanial form, there is…
General Features:External FeaturesMicroscopic, elongated organisms. 80 to 350μ.Oral groove is a shallow depression on the ventral part. Leads to the buccal cavity, which has a basal mouth called Cytostome.Pellicle: Internal…
Asexual ReproductionEarly Protozoans adopted this method as the primary means of multiplication.Enabled them to build up large populations in shortest possible time.Binary fission, multiple fission, budding, plasmotomy etc.Best suited to…