Animal Kingdom Classification

Phylum Mollusca

• Bilaterally symmetrical and triploblastic
• Less segmented body
• Well-developed organ and organ system
• Typically, open circulatory system
• Limbs are present
• Examples: Snails, Octopus

Phylum Echinodermata

• Radial symmetry and triploblastic
• Have true coelom
• Hard calcium carbonate skeleton structure
• Free-living marine animals
• Examples: Sea Urchins, Starfish

Phylum Hemichordata

• Soft, fragile, and divided into a proboscis
• Single-layered epidermis
• Worm-like marine animals with an organ-system level of organization
• Open circulatory system
• Respire through gills
• Separate sexes and external fertilization
• Development is direct
• Examples: Acorn Worms, Cephalodiscus

Phylum Chordata

• Bilaterally symmetrical, triploblastic with an organ-system level of classification
• Possess a notochord and a nerve cord
• Closed circulatory system
• Sub-phyla: Urochordata, Cephalochordata, Vertebrata
• Examples: Reptiles, Mammals

Phylum Platyhelminthes

• Dorsoventrally flattened body
• Complex and differentiated body structure
• Tissues are differentiated from three layers of cells and are triploblastic
• No true internal cavity or coelom
• Bilateral symmetry
• Either free-living (Planaria) or parasitic (liver flukes)
• Examples: Tapeworm, Planaria

Phylum Nematoda

• Cylindrical body
• Bilaterally symmetrical and triploblastic
• Pseudocoelom, a false body cavity
• Parasitic and causes diseases such as elephantiasis, ascariasis
• Examples: Ascaris, Wuchereria

Phylum Annelida

• Segmented cylindrical body
• Body is differentiated into head and tail
• Bilaterally symmetrical and triploblastic
• True body cavity
• Habitat: marine, freshwater, and land
• Examples: Earthworm, Leech

Phylum Arthropoda

• Jointed appendages
• Segmented body
• Bilaterally symmetrical
• Exoskeleton and a true body cavity
• Well-differentiated organ and organ system
• Open circulatory system, but no differentiated blood vessels
• Examples: Spiders, Butterflies, Mosquitoes

Kingdom Animalia

• Multicellular eukaryotes
• Heterotrophic mode of nutrition
• No chlorophyll or cell wall
• Classified into ten different subphyla
• Phyla: Porifera, Coelenterata (Cnidaria), Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata

Phylum Porifera

• Non-motile, multicellular organisms with a hard outer skeleton
• Porous body
• Pores on the body create a canal system for substance circulation
• Not differentiated into head and tail
• No well-developed organ or organ system
• Marine habitat
• Examples: Spongilla, Sycon

Phylum Coelenterata (Cnidaria)

• Hollow body cavity
• Body is differentiated into two ends
• Aquatic animals
• Body made of two layers of cells: inner and outer linings
• Live in colonies (corals) as well as solitary (Sea anemone)
• Examples: Hydra, Jellyfish