Animal Kingdom Revision

Phylums (11)

1. Porifera
2. Coelenterata (Cnidaria)
3. Ctenophora
4. Platyhelminthes (Flatworms)
5. Nematoda (Roundworms)
6. Annelida
7. Arthropoda
8. Mollusca
9. Echinodermata
10. Hemichordata
11. Chordata

7 Characteristics

1. Level of Organization
   • Porifera: Cellular level
   • Coelenterata, Ctenophora: Tissue level
   • Others: Organ level
2. Body Plan
   • Porifera: Cell aggregate body plan
   • Coelenterata, Ctenophora, Platyhelminthes: Blind sac
   • Nematoda to Chordata: Tube within tube
3. Circulatory System
   • Open: Arthropods, Molluscs (with some exceptions), Hemichordata
   • Closed: Annelida, Chordata
4. Germ Layer
   • Diploblastic: Coelenterata, Ctenophora
   • Triploblastic: All others
5. Body Cavity (Coelom)
   • Acoelomate: Porifera
   • Pseudocoelomate: Aschelminthes
   • True Coelomate: All others
6. Symmetry
   • Radial Symmetry: Coelenterata, Adult Echinodermata
   • Bilateral Symmetry: All others (Larva of Echinodermata)
   • Asymmetry: Most Porifera
7. Segmentation
   • Internal and External: Annelida, Arthropoda, Chordata
   • Only External: Arthropoda
   • Only Internal: Chordata
8. Presence of Notochord
   • Notochord Present: Chordata
   • Notochord Absent: All others

Porifera

• Other Name: Sponges
• Characteristics: Asymmetrical, predominantly marine, Ostia, Spongocoel, Collar cells
• Reproduction: Asexual (Fragmentation), Sexual (Bisexual, Internal fertilization, Indirect development)
• Examples: Euplectella, Spongilla, Sycon

Coelenterata (Cnidaria)

• Other Name: Cnidaria
• Characteristics: Cnidoblasts, Radial symmetry, Tissue level, Gastrovascular cavity
• Reproduction: Both asexual and sexual, Internal fertilization, Indirect development
• Examples: Hydra, Aurelia (Jellyfish), Adamsia, Pennatula, Gorgonia, Physalia

Ctenophora

• Characteristics: Predominantly marine, Bioluminescent, Eight comb plates
• Reproduction: Only sexual, Bisexual, External fertilization, Indirect development
• Examples: Pleurobrachia, Ctenoplana

Platyhelminthes (Flatworms)

• Characteristics: Organ level, Triploblastic, Bilateral symmetry, Incomplete digestive system, Flame cells
• Reproduction: Bisexual, Internal fertilization, Indirect development
• Examples: Taenia (Tapeworm), Planaria, Fasciola (Liver fluke)

Nematoda (Roundworms)

• Characteristics: Tube within tube body plan, Pseudocoelomate, Unisexual
• Reproduction: Unisexual, Internal fertilization, Both direct and indirect development
• Examples: Ascaris (Roundworm), Ancylostoma (Hookworm), Wuchereria (Filarial worm)

Annelida

• Characteristics: True coelomate, Closed circulatory system, Metamerism
• Reproduction: Bisexual, External fertilization, Direct development
• Examples: Earthworm (Lumbricus), Leech (Hirudinaria), Nereis

Arthropoda

• Unique Feature: Jointed appendages
• Characteristics: Largest phylum, Chitinous exoskeleton, Body three parts: head, thorax, abdomen
• Reproduction: Mostly unisexual, Internal fertilization, Indirect development
• Examples: Insects, Spiders, Crustaceans (Crabs), Lac insect

Mollusca

• Second largest phylum
• Characteristics: Unsegmented body, Mantle, Radula, Calcareous shell
• Reproduction: Mostly unisexual, Internal fertilization, Indirect development
• Examples: Sepia (Cuttlefish), Octopus, Apple snail, Chiton

Echinodermata

• Characteristics: Exclusively marine, Radial symmetry (adult), Endoskeleton, Water vascular system
• Reproduction: Unisexual, External fertilization, Indirect development
• Examples: Asterias (Starfish), Echinus (Sea urchin), Holothuria (Sea cucumber)

Hemichordata

• Formerly a subphylum of Chordata
• Characteristics: Worm-like, Body three parts: proboscis, collar, trunk
• Reproduction: Unisexual, External fertilization, Indirect development
• Examples: Balanoglossus, Saccoglossus

Chordata

• Characteristics: Notochord, Pharyngeal gill slits, Dorsal nerve cord, Post-anal tail
• Subphylums:
  • Urochordata: Notochord in larva, Examples: Ascidia, Salpa
  • Cephalochordata: Notochord in larva and adult, Examples: Branchiostoma (Lancelet)
  • Vertebrata: Notochord in embryonic stage, replaced by vertebral column
    • Agnatha (jawless): Cyclostomata (Petromyzon, Myxine)
    • Gnathostomata (jawed): Pisces (Fishes) and Tetrapoda
      • Chondrichthyes (Cartilaginous fish): Shark
      • Osteichthyes (Bony fish): Rohu
      • Amphibia: Dual life (water and land), Examples: Frog (Rana), Hyla (Tree frog)
      • Reptilia (Reptiles): Scales, Examples: Cobra, Crocodile
      • Aves (Birds): Flying, Examples: Crow, Vulture, Toad
      • Mammalia (Mammals): Mammary glands, Examples: Human, Whale

Other Important Points

• Exclusively Marine: Ctenophora, Echinodermata, Hemichordata, Urochordata, Cephalochordata
• External Fertilization: Ctenophora, Annelida, Echinodermata, Hemichordata, Amphibia
• Direct Development: Only in Annelida (with exception of Nereis)
• Most higher groups are unisexual

Note: All examples and main points covered in the syllabus.