Five Kingdom Classification
ICSE Class 9 · Biology · Chapter 8
What this chapter covers
- Kingdom Animalia and the basis of grouping animals
- Phylum Porifera: the sponges
- Phylum Coelenterata: Hydra, jellyfish and corals
- Phylum Platyhelminthes: the flatworms
- Phylum Nemathelminthes: the roundworms
- Phylum Annelida: the segmented worms
- Phylum Arthropoda: animals with jointed legs
- Phylum Mollusca: soft-bodied animals
- Phylum Echinodermata: spiny-skinned animals
- Phylum Chordata: non-chordates and chordates compared
- Class Pisces: the fishes
- Class Amphibia: frogs, toads and salamanders
- Class Reptilia: lizards, snakes, turtles and crocodiles
- Class Aves: the birds
- Class Mammalia: the mammals
Key points
- The five kingdoms are Monera, Protista, Fungi, Plantae and Animalia; animals are multicellular, eukaryotic, heterotrophic and have no cell wall.
- Animals are grouped by level of organisation, symmetry, germ layers, body cavity, segmentation and the presence of a notochord.
- Porifera: pores (ostia), osculum, collar cells, spicules or spongin, cellular level, sessile; Sycon, Spongilla, Euspongia.
- Coelenterata: diploblastic, radial symmetry, coelenteron with one opening, tentacles with cnidoblasts, polyp and medusa forms; Hydra, Aurelia, sea anemone, corals.
- Platyhelminthes: flat, triploblastic, acoelomate, flame cells, mostly parasitic and hermaphrodite; Planaria, Fasciola, Taenia.
- Nemathelminthes: cylindrical, unsegmented, pseudocoelomate, complete gut, sexes separate; Ascaris, Wuchereria, hookworm.
- Annelida: metameric segmentation, true coelom, setae, closed circulation, nephridia; earthworm, leech, Nereis.
- Arthropoda: the largest phylum, jointed legs, chitinous exoskeleton, moulting, open circulation; insects, crustaceans, arachnids, myriapods.
- Mollusca: soft unsegmented body with head, foot, visceral mass and mantle, usually a calcareous shell; Pila, Unio, Sepia, Octopus.
- Echinodermata: marine, spiny skin, pentaradial adults, water vascular system with tube feet; starfish, sea urchin, sea cucumber.
- Chordates have a notochord, a dorsal hollow nerve cord and pharyngeal gill slits at some stage; in vertebrates a backbone replaces the notochord.
- Pisces (scales, fins, gills, two-chambered heart), Amphibia (moist skin, double life, metamorphosis) and Reptilia (dry scales, shelled eggs on land) are cold-blooded.
- Aves (feathers, wings, pneumatic bones, beak) and Mammalia (hair, mammary glands, diaphragm, mostly viviparous) are warm-blooded with four-chambered hearts.
Questions answered
Name the five kingdoms and state two features that place an organism in Kingdom Animalia.
Monera, Protista, Fungi, Plantae and Animalia. Animals are multicellular eukaryotes whose cells have no cell wall, and they are heterotrophic, obtaining food by eating other organisms.
Define the coelom. Name one acoelomate, one pseudocoelomate and one coelomate animal.
The coelom is the fluid-filled body cavity between the body wall and the gut that is lined on all sides by mesoderm. Tapeworm is acoelomate, Ascaris is pseudocoelomate and the earthworm is coelomate.
Distinguish between diploblastic and triploblastic animals, with one example of each.
Diploblastic animals develop from two germ layers, ectoderm and endoderm, as in Hydra. Triploblastic animals develop from three germ layers, with mesoderm in between, as in the earthworm.
Name the openings through which water enters and leaves a sponge, and the cells that keep the water moving.
Water enters through the ostia and leaves through the osculum; the collar cells, or choanocytes, keep it moving with their flagella.
What are cnidoblasts, and why are they useful to a coelenterate?
Cnidoblasts are stinging cells, mainly on the tentacles, each containing a nematocyst thread. They paralyse prey and defend the animal against enemies.
Give two differences between Platyhelminthes and Nemathelminthes.
Flatworms are dorsoventrally flattened, while roundworms are cylindrical. Flatworms are acoelomate with a gut having only a mouth (or no gut), while roundworms are pseudocoelomate with a complete gut having both mouth and anus. Most flatworms are hermaphrodite, while roundworm sexes are separate.
Name the phylum and the disease caused by each: (a) Taenia, (b) Wuchereria, (c) Ascaris.
(a) Platyhelminthes, taeniasis. (b) Nemathelminthes, filariasis. (c) Nemathelminthes, ascariasis.
Why is the earthworm called the farmer's friend, and to which phylum does it belong?
Its burrows loosen and aerate the soil and let water reach the roots, and its castings make the soil fertile. It belongs to Annelida.
Past board exam questions
ICSE 2019 sample paper · 1 mark
The group of plants having naked seeds:
- Angiosperms
- Bryophyta
- Pteridophyta
- Gymnosperms
Show answer
Gymnosperms
ICSE 2019 sample paper · 5 marks
Give an example for each of the following: (i) A poriferan (ii) An antibiotic (iii) A coelenterate (iv) A deficiency disease (v) A mammal (vi) An annelid worm (vii) A reptilian (viii) A fat soluble vitamin (ix) An amphibian (x) A protein deficiency disease.
Show answer
(i) Sycon (or Spongilla)
(ii) Penicillin
(iii) Hydra
(iv) Scurvy (or rickets, beri-beri)
(v) Man (or cow, whale)
(vi) Earthworm
(vii) Lizard (or snake, crocodile)
(viii) Vitamin A (or D, E, K)
(ix) Frog (or toad)
(x) Kwashiorkor