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Phylum Echinodermata: Definition, Characteristics, Classification and Examples

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Phylum Echinodermata: Definition, Characteristics, Classification and Examples

Phylum Echinodermata (Gr., echinos = hedgehog ; derma = skin) is a group of marine invertebrates characterized by radial symmetry, a calcareous endoskeleton, and a water vascular system used for locomotion, feeding, and respiration. Members of this phylum include starfish, sea urchins, sand dollars, and sea cucumbers. They exhibit pentamerous symmetry in adults, have a unique regenerative ability, and possess tube feet for movement and adhesion. Echinoderms are exclusively marine and play essential roles in ocean ecosystems as predators, grazers, and sediment stabilizers.

Pearl Formation in Mollusca

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Stages of Pearl Formation in Mollusca

The “pearl” is literally formed by the mantle epithelium which becomes deposited around any external body or particles; these external particles or body invade in between the shell and mantle in any way.

Pila: Classification, Morphology, Torsion and Organs of Pallial Complex of Pila

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Organs of Pallial complex of Pila

Pila globosa is a common freshwater apple snail found in ponds, pools, tanks, lakes, marshes, paddy fields and sometimes even in streams and rivers of Northern India except Punjab. Pila is adapted to lead an amphibious life, it is provided with a pulmonary sac for aerial respiration and a gill or ctenidium for aquatic respiration.

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.