Class VIII Science EV Full

Chapter 1: Classification of Animal World

Biology Note – সহজে বোঝার জন্য সুন্দরভাবে সাজানো

Taxonomy কী?

Taxonomy: জীবের মধ্যে সাদৃশ্য ও বৈসাদৃশ্যের ভিত্তিতে শনাক্তকরণের পদ্ধতিকে বলে Taxonomy। অজানা জীবকে চেনার জন্য পরিচিত জীবের সাথে তুলনা করে শ্রেণিবদ্ধ করতে হয়।

Binomial Nomenclature: জীবের বৈজ্ঞানিক নাম দুই শব্দের হয়। উদাহরণ: মানুষ – Homo sapiens (Latin/Greek ভাষায়)।

Taxonomic Hierarchy

1. Kingdom
2. Phylum
3. Class
4. Order
5. Family
6. Genus
7. Species

Animal Kingdom (Kingdom Animalia)

Animal Kingdom-এর জীবগুলো multicellular, eukaryotic, heterotrophic এবং cell wall বিহীন। Vertebral column-এর উপস্থিতি/অনুপস্থিতির ভিত্তিতে দুই ভাগে বিভক্ত:

• Invertebrates – মেরুদণ্ড নেই
• Vertebrates – মেরুদণ্ড আছে

Classification of Invertebrates (৮টি Phylum)

1. Phylum Porifera (Sponges)

Body with pores, no true tissues or organs, mostly marine.

Example: Sycon, Spongilla, Euplectella

2. Phylum Coelenterata / Cnidaria

Radial symmetry, two cell layers, stinging cells (cnidocytes).

Example: Hydra, Jellyfish, Sea anemone

3. Phylum Platyhelminthes (Flatworms)

Bilateral symmetry, flattened body, acoelomate, mostly parasitic.

Example: Planaria, Tapeworm, Liver fluke

4. Phylum Nematoda (Roundworms)

Cylindrical, unsegmented, pseudocoelomate, many parasitic.

Example: Ascaris, Hookworm, Filarial worm

5. Phylum Annelida (Segmented worms)

Segmented body, true coelom, closed circulatory system.

Example: Earthworm, Leech, Nereis

6. Phylum Arthropoda

Largest phylum, jointed appendages, chitin exoskeleton.

Example: Insects, Spiders, Crabs

7. Phylum Mollusca

Soft body, often with shell, muscular foot and mantle.

Example: Snail, Octopus, Mussel

8. Phylum Echinodermata

Spiny skin, water vascular system, marine only.

Example: Starfish, Sea urchin, Sea cucumber

Summary Table

Phylum	Symmetry	Body Cavity	Example(s)
Porifera	Asymmetrical	No true cavity	Sycon, Spongilla
Cnidaria	Radial	No true cavity	Hydra, Jellyfish
Platyhelminthes	Bilateral	Acoelomate	Tapeworm, Planaria
Nematoda	Bilateral	Pseudocoelomate	Ascaris, Hookworm
Annelida	Bilateral	True coelom	Earthworm, Leech
Arthropoda	Bilateral	True coelom	Insects, Crabs
Mollusca	Bilateral	True coelom	Snail, Octopus
Echinodermata	Radial (adult)	True coelom	Starfish, Sea urchin

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CH-01 Classification of Animal Worlds

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CH-02 Growth and Heredity

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CH-03 Diffusion, Osmosis

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CH-04 Reproductions in Plants

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CH-05 Coordination and Secretion

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CH-06 The Structures of Atoms

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CH-07 The Earth and Gravitation

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CH-08 Chemical Reaction

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CH-09 Electric Circuits

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CH-10 Acid, Base and Salt

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CH-11 Light

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CH-12 Outer Space and Satellites

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CH-13 Food and Nutrition

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CH-14 Environment and Ecosystem

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