Animal Kingdom Lecture

Introduction

• Class: 11th Biology, Chapter 4
• Importance: Vital for NEET exam preparation

RH Whittaker's Five Kingdom Classification

Basis of Classification

• First-hour concept: Foundation of the chapter
• Monera: Unicellular, prokaryotic
• Protista, Fungi, Plantae, Animalia: Eukaryotic
• Animalia: Multicellular, heterotrophic, holozoic nutrition, no cell walls
• Fungi: Heterotrophic with a cell wall
• Plantae: Autotrophic with a cellulose cell wall

Levels of Organization

• Protoplasmic Level: Function performed by a single cell (e.g., Amoeba)
• Cellular Level: Loose aggregates of cells (e.g., Porifera)
• Tissue Level: Similar cells perform a function together (e.g., Cnidaria)
• Organ Level: Tissues forming organs (e.g., Platyhelminthes)
• Organ System Level: Organs forming systems (e.g., from Annelida to Mammalia)

Body Plans

• Blind Sac: Single opening for mouth and anus (e.g., Cnidaria, Platyhelminthes)
• Tube within Tube: Two openings (mouth and anus) (e.g., Aschelminthes to Chordates)
• Cell Aggregate: Primitive body plan (e.g., Porifera)

Circulatory System

• Open: Heart pumps blood into open spaces (e.g., Arthropoda, Mollusca)
• Closed: Blood is enclosed within vessels (e.g., Annelida, Chordata)

Symmetry

• Radial Symmetry: Identical halves through various planes (e.g., Cnidaria, Echinodermata)
• Bilateral Symmetry: Only one plane divides the body (e.g., Platyhelminthes to Chordata)
• Asymmetry: No plane divides the body into equal halves (e.g., Porifera)

Germ Layers

• Diploblastic: Two layers (ectoderm and endoderm) (e.g., Cnidaria)
• Triploblastic: Three layers (ectoderm, mesoderm, endoderm) (e.g., from Platyhelminthes to Chordates)

Coelom

• Acoelomate: No body cavity (e.g., Platyhelminthes)
• Pseudocoelomate: Body cavity not lined by mesoderm (e.g., Aschelminthes)
• Coelomate: True body cavity lined by mesoderm (e.g., from Annelida to Chordates)

Segmentation

• Metamerism: Segmentation both externally and internally (e.g., Annelida)

Notochord

• Notochord Presence: Classification into chordates and non-chordates

Phylum Overviews

Phylum Porifera

• Common name: Sponges
• Habitat: Mostly marine, some freshwater
• Symmetry: Mostly asymmetrical
• Organization: Cellular level, with unique water canal system
• Skeleton: Spicules and spongin fibers
• Reproduction: Both asexual (fragmentation, gemmule formation) and sexual (hermaphrodite, internal fertilization)
• Examples: Sycon, Euspongia, Spongilla

Phylum Cnidaria (Coelenterata)

• Common names: Hydra, Jellyfish, Sea anemones
• Body Forms: Polyp (e.g., Hydra) and Medusa (e.g., Aurelia)
• Symmetry: Radial symmetry
• Unique Feature: Nematocysts or stinging cells
• Reproduction: Both asexual (budding) and sexual
• Examples: Physalia, Adamsia, Pennatula

Phylum Ctenophora

• Common names: Comb jellies, Sea walnuts
• Habitat: Exclusively marine
• Unique Feature: Bioluminescence
• Symmetry: Radial symmetry
• Reproduction: Sexual, external fertilization
• Examples: Pleurobrachia, Ctenoplana

Phylum Platyhelminthes

• Common names: Flatworms
• Habitat: Mostly parasitic, some free-living
• Symmetry: Bilateral symmetry
• Organization: Organ level, triploblastic, acoelomate
• Unique Structures: Flame cells for excretion
• Examples: Taenia (Tapeworm), Fasciola (Liver fluke), Planaria

Phylum Aschelminthes (Nematoda)

• Common names: Roundworms
• Habitat: Aquatic, terrestrial, parasitic
• Symmetry: Bilateral
• Organization: Organ system level, triploblastic, pseudocoelomate
• Reproduction: Sexual, internal fertilization
• Examples: Ascaris, Wuchereria (Filarial worm)

Phylum Annelida

• Common names: Segmented worms
• Habitat: Aquatic, terrestrial, some ectoparasitic
• Symmetry: Bilateral
• Organization: Organ system level, triploblastic, coelomate
• Unique Structures: Nephridia for excretion, parapodia in Nereis
• Examples: Earthworm, Leech, Nereis

Phylum Arthropoda

• Characteristics: Exoskeleton, segmented body, jointed appendages
• Classes: Insecta, Crustacea, Arachnida
• Symmetry: Bilateral
• Organization: Organ system level
• Reproduction: Mostly sexual, internal fertilization
• Examples: Cockroach, Crab, Spider

Phylum Mollusca

• Characteristics: Soft-bodied, often with a calcareous shell
• Symmetry: Bilateral
• Organization: Organ system level
• Examples: Pila (Apple snail), Sepia (Cuttlefish), Loligo (Squid)

Phylum Echinodermata

• Characteristics: Spiny skinned, marine
• Symmetry: Radial (adults), Bilateral (larvae)
• Unique Feature: Water vascular system
• Reproduction: Sexual, external fertilization
• Examples: Starfish, Sea urchin, Brittle star

Phylum Hemichordata

• Characteristics: Marine worm-like
• Symmetry: Bilateral
• Coelom: True
• Organization: Organ system level
• Examples: Balanoglossus, Saccoglossus

Phylum Chordata

Subphylum Overview

• Urochordata: Notochord in larval tail (e.g., Ascidians)
• Cephalochordata: Notochord throughout life, head to tail (e.g., Amphioxus)
• Vertebrata: Notochord replaced by vertebral column

Classes of Subphylum Vertebrata

1. Cyclostomata: Jawless vertebrates (e.g., Lampreys, Hagfish)
2. Pisces: True fishes
   • Chondrichthyes: Cartilaginous fishes (e.g., Sharks, Rays)
   • Osteichthyes: Bony fishes (e.g., Labeo, Scoliodon)
3. Amphibia: Dual life (e.g., Frogs, Salamanders)
4. Reptilia: Crawling vertebrates (e.g., Snakes, Lizards)
5. Aves: Birds (e.g., Pigeons, Sparrows)
6. Mammalia: Mammals with mammary glands (e.g., Humans, Whales)

Important Concepts

• External Fertilization: In water (e.g., Amphibians)
• Internal Fertilization: In the body (e.g., Reptiles, Mammals)
• Direct Development: Offspring resemble parents (e.g., Mammals)
• Indirect Development: Larval stages (e.g., Frogs)

Summary

• Diverse and expansive classification system from simple to complex organisms
• Each phylum with unique and identifying characteristics
• Important for NEET exam preparation, emphasizing understanding of structure, function, and evolutionary relationships.