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Phylum Mollusca: Definition, Characteristics, Classification and Examples

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Phylum Mollusca: Definition, Characteristics, Classification and Examples

Phylum Mollusca (L., mollis = soft) is a major group in the animal kingdom that includes soft-bodied invertebrates, often characterized by a calcareous shell, though not all members possess one. Molluscs exhibit a wide variety of body forms and habitats, ranging from marine to freshwater and terrestrial environments. Key features of this phylum include a muscular foot used for locomotion, a mantle that secretes the shell (if present), and a visceral mass housing the internal organs. The phylum includes diverse classes such as Gastropoda (snails and slugs), Bivalvia (clams and mussels), Cephalopoda (octopuses and squids), and others. Molluscs play important ecological and economic roles, from maintaining marine ecosystems to serving as food for humans.

Phylum Onychophora | Peripatus: Diagram, Characteristics and Affinities

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Phylum Onychophora Peripatus diagram

Peripatus is a connecting link between Annelida and Arthropoda. Peripatus and related animals belong to the Phylum Onychophora, which was conventionally classified with arthropoda as one of its classes. But the modern classification has given to it the status of an independent phylum.

Palaemon: Diagram, Characteristics, Classification, Morphology and Reproductive System

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Diagrammatic structure of Palaemon

Palaemon (The Freshwater Prawn) is studied in the Indian Universities as a typical representative of the class Crustacea.

Vaccines: Definition, Types and Production of Vaccines

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Steps in the Production of Vaccines

Vaccines (Latin: vacca = cow) preparation/suspension or extract of dead/attenuated (weakened) germs of a disease which, on inoculation (injection) into a healthy person, provides temporary/permanent active/passive immunity by inducing antibody formation.

HIV/AIDS virus: Structure, Symptoms, Treatment, Prevention and Mode of Action

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Human Immunodeficiency Virus structure

What is HIV/AIDS virus? HIV (Human immunodeficiency virus) is a retrovirus that belongs to the genus Lentivirus, part of the family Retroviridae. It is the causative agent of AIDS (Acquired Immunodeficiency Syndrome).

Phylum Arthropoda: Definition, Characteristics, Classification and Examples

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Phylum Arthropoda: Definition, Characteristics, Classification and Examples

Phylum Arthropoda (Gr., arthros = jointed ; podos = foot) is the largest and most diverse group of animals in the animal kingdom, characterized by their segmented bodies, jointed appendages, and exoskeleton made of chitin. This phylum includes insects (e.g., butterflies, beetles), arachnids (e.g., spiders, scorpions), crustaceans (e.g., crabs, lobsters), and myriapods (e.g., centipedes, millipedes). Arthropods play essential ecological roles, such as pollinators, decomposers, and as part of the food web.

Tobacco Mosaic Virus: History, Importance , Structure and Symptoms

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Tobacco Mosaic Virus diagram

Tobacco Mosaic Virus (TMV) is a plant virus that mainly infects tobacco plants but can also affect other crops, including tomatoes and peppers. It is a rod-shaped virus, one of the first ever discovered and studied.

Bacteriophages: Definition, Structure, Types and Life cycle

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Diagrammatic structure of Bacteriophage

Bacteriophages are the viruses which infect bacteria. These viruses that parasitizes the bacteria. Bacteriophages were discovered independently by Frederick William Twort in 1915 and Félix d’Hérelle in 1917.

Phylum Annelida: Definition, Characteristics, Classification and Examples

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Phylum Annelida: Definition, Characteristics, Classification and Examples

Phylum Annelida (L., annelus = little ring or F., anneler = to arrange in rings) is a group of bilaterally symmetrical, coelomate, and segmented animals known commonly as segmented worms. Members of this phylum exhibit a body divided into repeated segments called metameres, which give them structural and functional division. Annelids are triploblastic and possess a true coelom, which is divided by septa, and a closed circulatory system. They have a complete digestive system, a well-developed nervous system with a ventral nerve cord, and excretory structures called nephridia. Respiration occurs through the body surface, gills, or parapodia.

Phylum Aschelminthes: Definition, Characteristics, Classification and Examples

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Definition,Characteristics, Classification and Examples of Phylum Aschelminthes

Phylum Aschelminthes (Gr., askes = cavity ; helmins = worm) is a group of bilaterally symmetrical, unsegmented, and pseudocoelomate animals. They are typically characterized by a cylindrical or thread-like body covered with a tough, flexible cuticle. The phylum includes organisms that are predominantly aquatic or parasitic in nature, such as nematodes (roundworms).