S

Five Kingdom Classification and Vertebrate Diversity Study Notes

Genus to Kingdom: hierarchical levels with examples

  • Genus: the next higher category above species; related species that are similar but can be distinct in features. Example: hill crow (jungle crow) vs house crow are different species but belong to the same genus Corvus.

    • Hill crow (Corvus) and house crow (Corvus) differ in size, colour, beak, etc., yet are both crows.

    • They cannot interbreed, but are easily distinguished from other birds.

  • Family: a group of genera with common characteristics. Example: Panthera leo (lion) and Panthera tigris (tiger) are different species but belong to the same genus Panthera; a larger family Felidae includes the domestic cat and related cats.

  • Order: a group of related families with some common features. Example: Felidae (lions, tigers, cats) and Canidae (dogs, foxes, jackals) together form the order Carnivora.

  • Class: related orders form a class. Examples: dogs, cats, bats, whales, monkeys, humans—all are in Class Mammalia (mammals) due to shared features like mammary glands, hair, etc.

  • Phylum: the largest division that groups related classes. Example: all mammals, birds, reptiles, frogs, fishes belong to Phylum Chordata, which have a notochord at some stage.

  • Kingdom: the largest division in the classification system; the major kingdoms discussed are MONERA, PROTISTA, FUNGI, PLANTAE, ANIMALIA.

Five Kingdom Classification (summary)

  • The five kingdoms under the recent scheme are:

    • 1 MONERA

    • 2 PROTISTA

    • 3 FUNGI

    • 4 PLANTAE

    • 5 ANIMALIA

Kingdom MONERA (unicellular & prokaryotic)

  • Mostly single-celled organisms; do not have an organized nucleus (prokaryotic).

  • Nuclear material (DNA) is distributed in the cell without a nuclear membrane.

  • No membrane-bound organelles such as mitochondria or chloroplasts.

  • Common examples: bacteria (Fig. 8.3) with shapes such as rods, spirals, spheres; occur singly or in groups/chains.

  • Conceptually the simplest form of life in this scheme.

Kingdom PROTISTA (Protoctista) (eukaryotic and mostly unicellular)

  • Eukaryotic cells; most organisms are single-celled, some colonial or few multicellular forms.

  • Include both unicellular green autotrophs (e.g., Chlamydomonas) and unicellular non-green heterotrophs (e.g., Amoeba, Euglena, Paramecium).

  • Some multicellular photosynthetic plant-like Protists (e.g., Pandorina) are also included in Protista.

  • Key idea: eukaryotic, mostly single-celled, with defined nucleus.

Kingdom FUNGI (usually multicellular, eukaryotic, achlorophyllous and saprophytic)

  • Most fungi are made up of thread-like hyphae rather than discrete cells; nuclei are distributed in the continuous cytoplasm.

  • Generally saprophytic (decomposers) and some are parasitic.

  • Common examples: Bread mould, Toadstool, Yeast, Penicillium (Fig. 8.5).

Kingdom PLANTAE (multicellular, eukaryotic and autotrophic)

  • Multicellular and autotrophic (photosynthesis via chlorophyll).

  • Plant body can be differentiated into roots, stems, leaves, and reproductive organs (in general).

  • Seeds are produced in some groups; division of Plantae is into five divisions:

    • Thallophyta (algae)

    • Bryophyta (mosses)

    • Pteridophyta (ferns)

    • Gymnosperms (pine, etc.)

    • Angiosperms (flowering plants)

Thallophyta (algae)

  • Multicellular algae; autotrophic (contain chlorophyll).

  • Thallus-like body: plant body not clearly differentiated into roots, stems, or leaves.

  • Primarily aquatic.

Bryophyta (mosses and liverworts)

  • Autotrophic; plant body lacks true roots, stems, and leaves; instead they have rhizoids, caulids, and phyllids.

Pteridophyta (ferns)

  • Plant body differentiated into roots, stems, and leaves.

  • Leaves often have leaflets bearing spores on the underside; non-flowering plants.

Gymnosperms (e.g., Cycas, pine, fir)

  • Bear naked seeds (seeds not enclosed in fruits); seeds borne in structures like cones; include both male and female cones.

  • They can be trees or shrubs.

  • Two types mentioned: cycads and conifers.

Angiosperms (flowering plants)

  • Highly developed plant body; differentiated into roots, stems, leaves, flowers, and fruits.

  • Seeds enclosed in a fruit.

  • Further divided into:

    • Monocots: seeds have one cotyledon; leaves with parallel venation; root system is fibrous (e.g., maize, rice, grasses).

    • Dicots: seeds have two cotyledons; leaves with reticulate venation; root system is a tap root (e.g., pea, potato, apple, sunflower, rose).

Kingdom ANIMALIA (multicellular, eukaryotic and heterotrophic)

  • Multicellular organisms that lack a cell wall; most are mobile; some (e.g., sponges, corals) are sessile.

  • Heterotrophic nutrition (obtain food by consumption).

  • Animals range from simple forms to highly complex organisms; diversity is vast.

Naming and Organism Diversity (extra info useful to know)

  • Common names are variable and sometimes confusing across regions.

  • In India, many animals/plants have multiple local names for the same species.

  • Example prompt: Pumpkin illustrates local naming diversity in common use.

Major Groups of Animals (nine major phyla)

  • The animal kingdom is divided into nine major phyla:

    • Phylum Porifera

    • Phylum Cnidaria

    • Phylum Platyhelminthes

    • Phylum Nematoda

    • Phylum Annelida

    • Phylum Arthropoda

    • Phylum Mollusca

    • Phylum Echinodermata

    • Phylum Chordata

Invertebrate vs Vertebrate (summary differences)

  • Invertebrates (no backbone):

    • No internal skeleton

    • Backbone not present

    • Tail is typically absent (anus at the tip of the back end)

    • Heart on the dorsal side

    • Nerve cord ventral and solid

    • May have three or more pairs of limbs if present

    • Haemoglobin, if present, dissolved in blood

  • Vertebrates (with backbone):

    • Internal skeleton

    • Backbone present

    • Tail usually present

    • Heart on the ventral side

    • Nerve (spinal) cord dorsal and hollow

    • Typically two pairs of limbs

    • Haemoglobin present in red blood cells

Porifera (Pore-bearing animals)

  • Examples: Sycon and Bath sponge (Fig. 8.7)

  • Characteristics:

    • Simplest multicellular animals; body consists of a hollow tube.

    • No single mouth; numerous pores (ostia) and an exit opening (osculum).

    • Water enters through pores, exits via osculum.

    • Body supported by spicules.

Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata (overview)

  • The phyla listed include the following basic facets as per the chapter:

    • Cnidaria: (not detailed in the provided content; included as a major phylum)

    • Platyhelminthes: (not detailed in the provided content; included as a major phylum)

    • Nematoda: (not detailed in the provided content; included as a major phylum)

    • Annelida: (not detailed in the provided content; included as a major phylum)

    • Arthropoda: jointed-legged animals; examples: crayfish, crabs, millipede, centipede, insects, scorpions, spiders; largest animal phylum; features: jointed limbs, exoskeleton of chitin, moulting (ecdysis).

    • Mollusca: soft, unsegmented bodies with a calcareous shell; muscular foot; examples: snail, slug, oyster, mussel, clam, squid, octopus.

    • Echinodermata: starfish, brittle-star, sea-urchin, sea-cucumber; marine; unsegmented; exoskeleton; spiny surface; tube feet; radially symmetrical (often five-part).

Phylum Chordata (Vertebrata)

  • All chordates possess a notochord in the embryonic life; in most vertebrates the notochord is replaced by a backbone (vertebral column).

  • Vertebrates have a well-developed vertebral column forming the main axis of the skeleton; head, trunk, and two pairs of appendages.

  • Gill slits may be present at some stage of life.

  • Vertebrates are divided into five classes: Pisces, Amphibia, Reptilia, Aves, Mammalia.

Vertebrate Classes (8.9.1 summary)

  • (i) Pisces (Fishes):

    • Completely aquatic; two-chambered heart; breathe via gills; cold-blooded (poikilothermal).

    • Body covered with scales; fins present; no true limbs.

    • Two main types:

    • Cartilaginous fishes (skeleton made of cartilage) e.g., dogfish, skates.

    • Bony fishes (skeleton made of bone) e.g., carps, rohu, herring, trout.

    • Gill slits in bony fishes are covered by an operculum; cartilaginous fishes expose gill slits without a gill cover.

  • (ii) Amphibia (Frogs, Toads, Salamanders, Newts):

    • Spend most of life on land; eggs and larval stages aquatic.

    • Eggs laid in water; larvae (tetrapod stage) breathe with gills; adults use lungs.

    • Skin is smooth, non-scaly, moist/slimy; tympanic membrane (eardrum) lies on the skin; pentadactyl limbs.

    • Three-chambered heart; cold-blooded (ectothermic).

  • (iii) Reptilia (Lizards, Snakes, Turtles, Crocodilians, etc.)

    • Land-adapted; leathery eggs laid; lungs for breathing.

    • Dry, scaly skin; forelimbs adapted to various functions; often three-chambered heart (note: crocodilians have a four-chambered heart in many explanations; the standard simplified overview presents three-chambered for most reptiles).

    • Ears: tympanic membranes present in many species.

  • (iv) Aves (Birds):

    • Warm-blooded (homeothermic); aerial or flight-adapted.

    • Forelimbs modified into wings; feathers for locomotion and insulation.

    • Lungs for breathing; eggs laid with calcareous shells.

    • Four-chambered heart.

    • Examples: various birds (parrot, crow, pigeon, duck, etc.).

  • (v) Mammalia (Mammals):

    • Warm-blooded; usually bear live young (viviparous), with a couple of exceptions (e.g., platypus and echidna lay eggs).

    • Hair on the skin; mammary glands to nourish young.

    • Four-chambered heart; lungs for breathing; diaphragmatic separation of thorax and abdomen.

    • Typically external ears (pinnae) and, in males, testes housed in the scrotum.

Do You Know?

  • Cuckoo brood parasitism: The male cuckoo sings a distinctive call; the female lays eggs in the nests of other birds (e.g., in a crow's nest); the foster parent incubates the eggs and raises the cuckoo chick.

  • Ostrich facts: Largest and heaviest living bird; although flightless, it has powerful legs and is the fastest land runner; lays the largest eggs of any living bird; eyes are among the largest of land animals, occupying much of the skull.

Summary of Vertebrate Classification (quick reference)

  • Pisces: cold-blooded, aquatic; slimy, scaly skin; gills; 2-\text{chambered} heart; external fertilization; locomotion via fins; examples include sharks (cartilaginous) and bony fishes (bone skeletons).

  • Amphibia: cold-blooded; life partly aquatic; moist skin; gills in larvae; lungs in adults; 3-\text{chambered} heart; external fertilization.

  • Reptilia: cold-blooded; land-dwelling; dry, scaly skin; lungs; two pairs of limbs; 3-\text{chambered} heart; leathery eggs; external fertilization; examples include snakes and lizards.

  • Aves: warm-blooded; aerial; feathers; lungs; eggs with calcareous shells; 4-\text{chambered} heart; forelimbs as wings.

  • Mammalia: warm-blooded; hair; mammary glands; lungs; 4-\text{chambered} heart; typically external ears; many give birth to live young.

Practice and Review (Progress Checks)

  • Rearrange the following categories of animal grouping in a sequence from highest to lowest: Kingdom, Phylum, Class, Order, Genus, Species.

  • Tick the features that characterize vertebrates:

    • ext{(i)} Dorsal nerve cord

    • ext{(ii)} Haemoglobin dissolved

    • ext{(iii)} Three or more pairs of limbs

    • ext{(iv)} A tail behind the level of the anus

    • ext{(v)} Dorsal heart

Note on notation

  • Numbers and counts in this document are presented in LaTeX math mode where appropriate, e.g. 2, 3, 4, and terms like 2-\text{chambered} heart reflect the education material’s conventions.

  • When recalling the material, focus on how the hierarchy links to examples and how distinctive characteristics define each level or group.